Procedure for leaching at presence of hydrochloric acid for regeneration of valuable metal from ore

FIELD: metallurgy.

SUBSTANCE: there are performed following stages: ore leaching at presence of hydrochloric acid with formation of soluble chloride of metal in solution for leaching, addition of sulphuric acid and/or sulphur dioxide into solution for leaching, regeneration of solid sulphate of metal or sulphate of metal from solution for leaching, regeneration of hydrochloric acid and continuous transformation of at least part of hydrochloric acid from solution into vaporous phase. Further, vaporous hydrochloric acid is absorbed and returned to the leaching stage. The sulphuric acid and/or sulphur dioxide are added to solution for leaching during process of leaching or after it. Valuable metal is usually chosen from group including Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, metals of platinum group and gold. Metal in sulphate of metal or sulphite of metal corresponds to valuable metal or less valuable metal in comparison with metal leached from ore, for example, magnesium.

EFFECT: raised efficiency of procedure.

14 cl, 27 dwg, 1 tbl

 

The background to the present invention

The present invention relates to a method for leaching, which results in the accumulation or regeneration of hydrochloric acid and leaching of metal from ore chloride solution.

In the past, several methods were used relatively concentrated salt chloride solutions in the quality environment for leaching of base metals, one of the last options includes hydrometry way Outokumpu described in several patents, such as WO 2003/35916, WP 2003/89675 etc. it is Known that chloride salt solutions of high ionic strength mainly provide faster and more complete leaching compared with conventional relatively dilute sulfate environment. However, regeneration of the dissolved valuable materials from such salt solutions is a time-consuming process and eliminates the standard electrolytic processing.

For many years research in many research centers have been directed to the use of hydrochloric acid (chloride environment) for leaching of Nickel from lateritic ores, first of all we should mention the work in this area, conducted at the University glides them. Nmisa (N.M.Rice of Leeds University (see Rice 1989). When processing both types of ore, typical silicate (serpentine) and oxide ore (limonite), N. which was distributed optimal kinetic parameters, testified to the possibility of applying this system to the leaching of valuable metals such as Nickel, from a number of materials such as laterite. Of particular interest is the rapid kinetics (1 h) leaching at high temperatures, usually over 80°C, 4 M hydrochloric acid solution. Was developed conceptual framework (Rice and Strong, 1974) using leaching with hydrochloric acid to solubilize the valuable cobalt and Nickel, which are then removed by solvent extraction with subsequent hydrolysis and received in the form of Nickel hydroxide (using magnesia as a neutralizing agent), respectively. The main components that contribute to the consumption of the expensive hydrochloric acid, are impurities such as iron and magnesium. The iron chloride is removed from the solution by solvent extraction and processing at the stage of firing, by sputtering, thereby forming a stable hematite and regenerated hydrochloric acid, which is directed into the recirculation system to the stage of leaching. Similarly, the magnesium chloride is treated at the stage of firing, by sputtering, thereby forming magnesium (which is used as a commercial by-product and/or used as a neutralizing agent) and regenerated hydrochloric acid (returns to recirculate the pension system through leaching).

Found that approximately 70% of the world's natural reserves of Nickel contained in the laterite ore. Currently, only about 40% Nickel, produced in industry, extracted from laterite ores, and it is expected that by 2012 this figure will increase to approximately 50% (calculations Dalvi and others, 2004). Thus, currently, there is a need to develop a new process for recovery of Nickel and cobalt from laterite deposits, which is characterized by a significantly lower performance and above all lower capital costs compared with modern technologies. Moreover, taking into account reserves and future growth needs of Nickel approximately 4% (depending on various factors) the demand for Nickel will be 40000-45000 tons per year produced in the Nickel industry, to meet the needs (accounts Dalvi and others, 2004). Even if you use the additional development of new sources (stocks) of small sulphide deposits, the main projects involving new ways of development of laterite (such as acid leaching at high pressure Goro and Ravensthrope, new casting furnace such as furnace Koniambo, and new ways sulfide hydrometallurgical processing, the hat as a way Voisey''s Bay), all of these methods will not be able to meet the needs.

Geology and Mineralogy

Lateritic Nickel deposits include two basic layer (horizon), that is limonitic (hydrated iron oxide) surface material (0,8-1,5% Ni, low magnesium, high iron content) and a deeper layer, saprobity (hydrosilicate magnesium) material (1,5-3% Ni, high magnesium content, low iron content). These layers are formed by erosion of the source rock, in the form of minerals Fe-Mg-Si-o In the process of lateritization Ni and Co are concentrated in the 3-30 times compared to the original breed. The process of lateritization is dynamic, and deep incision is essentially a snapshot, and in the lower layer is relatively recently modified breed.

Many limonite deposits formed when excess of free silicon in the composition of the original rock) re-deposited after leaching of Mg-silicate structure with the formation of silicate deposits (example ore of this type is silicate Deposit Jacare. In milder conditions, erosion, for example, in a dry or cold climate, or limited movement of groundwater (poor drainage), the degree of leaching is reduced, which leads to the formation of SMC the practical clays. Deposits of clay (if present) are usually between limonite and saprolite areas (an example of such a Deposit is a Deposit Murrin, which contain in the deep section interspersed smectic zone). Near laterite mainland rock with a modified surface section are formed is enriched in Nickel (20% Ni) hydrated Mg-silicate minerals (known as garnierite). Garnierite most common in tectonically active layers, such as New Caledonia. Between mainland soil or a layer of garnierite (if present) and a layer of limonite or clay (if present) is located in a transition zone containing substantially modified magnesium silicate material called saprolite area. When erosion of the original rock may also be formed free silicon, occurring in the most permeable geological structures, such as zones of transverse shear, faults, veins and fractures (for a detailed review see Monhemius, 1987 and Elias, 2002).

And finally, as a result of uneven erosion (incision) laterite horizon, and also due to the uneven development of individual samples of ore, such as saprolite, can contain various amounts of other ores, such as limonite and/or clay. Thus, laterite as raw material is characterized by extremely variable the mineralogical composition and associated processing characteristics. The main sources of lateritic Nickel worldwide are ore limonite type and to a lesser extent ore saprolite type.

Practice modern methods

An important stage in the processing as possible is a natural enrichment, as in the processing of Nickel ore of high quality, the most reasonable is the efficiency of any process used. Unfortunately, both types of ore, limonite and saprolite difficult to enrichment, as Ni homogeneous mixed with the minerals goethite and magnesium silicate, respectively. There is a certain possibility of Fizicheskaya, but only if there is a large barren material, such as a large quartz (silica or saprolitic ores) or magnetite (limonitic ores).

The melting process

Saprolite ore usually contains 20-50% of free water and at the first stage it is removed by drying. Then the ore is calcined to remove the structured water with subsequent recovery of Ni and Fe to the metals in the furnace mixed with coke or coal. Mg, Si, etc. form a slag, which allows you to remove the liquid molten alloy of Ni-Fe. Then you need refining (remelting) to remove residual S, and Si. When using the production method of the matte require adding S in the kiln in reducing conditions. the ri is the interaction with the metal of Ni with Fe to form sulfides. This material is then melted, and the oxides form a slag, and sulfides form a Stein. Finally, through the Converter blow air for oxidation of the base Fe to slag.

Properties of the method:

the method is designed to handle saprolitic ores, primarily enriched Americom,

- marginal economic indicators of the quality of ore for projects "brown field" (update old enterprises) with a low value of approximately 1.7% of Ni, and for projects "brown field" (update old enterprises) with the high cost approximately 2.1% Ni (Dalvi and others, 2004),

the variability of the ore composition has to be neutralized in order to ensure the specified quality of the processed raw materials (as Ni, the melting point of the slag depends on SiO2/MgO and FeO and the like),

- the disadvantages of the melting process include high investment and energy costs, as well as aspects of environmental protection, therefore, the efficiency of the process largely depends on regional energy prices,

although the release of Ni is quite high (~90%), the yield of Co as a by-product or is too small or completely absent, firstly, due to the low content of Co in saprolitic ores and, secondly, due to the low yield (~50%), (Dalvi and others, 2004), really is particular, the presence of Co in the ferronickel is undesirable.

The process Caron

First, the ore is dried in a rotary kiln and fired in reducing conditions. Ni and Co is selectively restored at approximately 700°C to metals (approximately 10% of the Fe is partially restored). If the silicate content in the substrate is increased (due to processing more saprolite ore), then re-crystallization of forsterite (amorphous Mg-silicate) and when this occurs, the capture of Ni, that is, the Nickel is not amenable to leaching. Similarly higher temperature recovery and excess recovery leads to increased educational opportunities refractory phase (in relation to leaching). After cooling, the alloy is leached in an atmosphere of air in an oxidizing environment (air) in a solution of ammonia-ammonium carbonate (pH~10). Leached Ni (Co) and Fe form extremely durable linecomplete in solution. Ion iron (II) is oxidized to iron (III) and hydrolyzed to form gelatinizing hydroxide Fe (Co jointly precipitated with iron hydroxide and a significant portion cannot be regenerated). After separation system liquid - solid substance, a certain amount of Ni and the whole Co deposited in the form of sulfides in the presence of gaseous H2S (Co is less soluble compared to Ni). A solution of Ni (not containing Co) sitematerials with steam, this forms a basic carbonate Ni (solid phase), CO2and ammonia in the gaseous phase. CO2and ammonia is recovered for reuse in the absorption by water with formation of a solution of ammonia-ammonium carbonate. KEK Nickel carbonate or used as a commercial product, or subjected to further processing using a variety of methods final treatment for the regeneration of Ni carbonate or from solution (see Monhemius, 1987).

Properties of the method:

the method is designed to handle limonitic ores, although it can be used for processing certain types of saprolite (when the number of formed forsterite, which leads to increased losses of Nickel),

although most of the reagents (ammonia and CO2go to the recirculation system of the process, there is considerable loss (primarily due to the leaching of magnesium), in addition, require auxiliary reagents to obtain a product with a relatively high degree of purification,

more than 60% of the total consumed energy is used in the preliminary stages of the process (drying wet ore and the recovery annealing), while in the final stages of processing again by using the methods of hydrometallurgical processing, that is, the process from the energy point of view of the two which is extremely inefficient,

filtering is ineffective due to the jelly-like nature of the precipitated hydroxide of iron,

- low yield of extraction for both processes: pyrometallurgical (formation of forsterite) and hydrometallurgical (coprecipitation of Co and blocking videlectrix particles due to precipitation of Fe) processes, the total yield of Ni is approximately 75% Co 50%.

One should not expect that this technology can be used to develop new projects due to low yield of precious metals and the use of raw materials with low content of Ni (preferably limonite ore), in addition, these processes require high energy costs and reagents (see Dalvi and others, 2004).

The process of acid leaching at high pressure (HPAL)

In metallurgy the HPAL process is relatively simple, in the first stage using an acid decomposition at high temperature of more than 245°C. the Obtained suspension is neutralized with lime and decanted in a counter, then remove impurities and precipitated Ni and Co in the form of sulfide (H2S) or hydroxide (lime) or directly remove Ni and Co extraction solvent (scheme Goro). Optional further purification and separation include re-dissolution (if at planting get a solid substance) and cleaned using solvent extraction or selectionfailure. And, finally, the metal is recovered by electrolysis or by reduction with hydrogen, or Nickel oxide is obtained using pyrohydrolysis (chlorides used in the form SX or IX, but not for the leaching process).

Process properties:

the method is intended for processing limonitic ores and, thus, it can be used for more types of ore, compared with the method of melting (stocks limonite ore significantly exceed the reserves saprolite ore high quality), but the efficiency of the method largely depends on the content of total sinks acid, that is, Al (clay) and especially Mg (<4% is the generally accepted limit for economical processing),

- high corrosion at high temperatures, especially if there are chlorides (salt in water), corrosion resistance can be improved through the use of Ti alloys of high quality, which increases the cost of the process.

- high kapitalanlagen through the use of equipment under pressure and structural materials.

- cost of reagents are extremely high due to the absorbers acid (Mg, Al) and the need to maintain the initial level of acid (to eliminate the negative effect of education bisulfate, "at temperature"), and also due to the need neutral is saved after leaching (cost of lime),

- problems when using autoclaves in connection with the formation of scale, which leads to downtime, primarily in the processing of raw materials with high content of Mg and Al,

depending on the location of the plant is becoming increasingly important problem of disposal sulfidogenic wastewater.

Calculations (Dalvi and others, 2004) indicate that the efficiency of the method HPAL largely depends on the quality of raw materials, that is, the estimated lower limit of quality raw materials for new projects is 1.3% Ni, excluding compensation due to the consumption of acid below the average (see the Ambatovy project in Madagascar) or when using the nearest sources of cheap acid (e.g., stage of melting sulphides). Figure 1 shows the inefficiency of the HPAL process in respect of reagents used. It is established that the main reason for the consumption of acid is Mg, and to eliminate this disadvantage can only be due to the processing of ore with low Mg content (ore limonite type). In addition, approximately half of the cost associated with the need to fill the initial level of reagents (to compensate for the education of bisulfates "at temperature"), which in reality are not used for leaching). "More" acid is also required to add to neutralize the donkey leaching under pressure. The higher the density of the slurry (suspension), the less the cost of reagents affect the absolute value (cost/lb obtained Ni). However, there is a limit to the maximum density of the pulp due to restrictions on viscosity.

New developments

Currently in the industry there is a tendency of the development and design of effective ways of atmospheric leaching (AL), primarily due to decreased investment, and also for processing as limonite and saprolite.

The method is based on sulfates, open system

Usually limonite ore leached at high residual acid concentration, while saprolite ore (with a higher ability to neutralize) is then used to neutralize the residual acid and the acids formed by the hydrolysis of Fe. This approach not only provides cost savings to neutralize, but also additional extraction of Ni contained in saprolite ore. A combination of ways HPAL and atmospheric (after leaching) neutralization saprolite ore used in the development of the so-called method of acid leaching at elevated pressures (EPAL), which is currently used in the Ravensthorpe project in Western Australia. The nature of the processes claimed by the AM in patents in 1970 is. The way AM also firing for the partial recovery saprolite ore, that is, to improve its ability to neutralize. In the process, you can use the recirculation of any newamericanow Nickel and the balance (of which you have already removed the main number Mg) in the HPAL process (Monhemius, 1987).

Properties of the method EPAL:

atmospheric leaching kinetics is characterized by low, which, however, can largely compensate for low investment, that is a relatively cheap treatment duration (compared to the HPAL process),

- hydrolysis of Fe in atmospheric conditions and in dilute sulfate system can lead to the formation of products whose disposal causes problems of environmental protection,

even if the system is atmospheric leaching is effective in the removal of Fe (in the neutralization process/hydrolysis saprolite ore), still there is considerable loss of acid due to excessive leaching of Mg (however, these costs can be partially offset by the extra energy obtained in additional burning sulfur, as well as due to additional income from the sale of Nickel),

the way EPAL is characterized by large investments compared to the HPAL process,

- there are significant challenges on the utilizacii wastewater primarily due to ever increasing limitations of environmental protection.

When using AL in full in sulfate environment requires extremely aggressive (strong acid) leaching conditions to ensure a high yield of extraction of Ni and Co. Such conditions, in turn, cause significant limitations to neutralize saprolite material, which in turn leads to a significant loss of sulfate due to the magnesium in solution and may be in the form of jarosite residue (even if the working fluid used sea water). High consumption of reagents (especially expensive sulfur) and limitations on the protection of the environment minimises the effectiveness of the process. For this reason, have developed alternative ways to solve problems with Mg. In one such method, proposed by American Climax Inc. (previous name of the company-S), use the crystallization in an autoclave at 190-250°C for planting sulfate as monohydrate. Because this process requires the use of additional and expensive autoclave was proposed process SURAL (Sulzer, Switzerland, regeneration Schultz with acid leaching), which uses the crystallization by evaporation, thus receive epsomite MgSO4·7H2O). Specified sulfate, then the evaluation is to provide thermal decomposition with the formation of SO 2(which turned into sulphuric acid plant for the production of acid and sent to the recirculation system of the HPAL process) and a neutralizing agent, magnesia (MgO), which is sent in the recirculation system process (see Monhemius, 1987).

Recently patented by Skye Resources the atmospheric leaching process is almost identical to the process SURAL, except that the initial leaching is also atmospheric. Scheme of the process Skye shown in figure 2.

Properties of the method Skye (without introduction of the industry):

- it seems unlikely that even in extremely aggressive atmospheres atmospheric leaching (e.g., leaching using clay)that the extraction of Ni in sulfate environment is comparable to the HPAL process,

- replacement cost of the reagents on the cost of energy/fuel is effective or ineffective depending on the region,

- trouble getting stable in the environment of the products of hydrolysis of Fe,

- crystallization of magnesium sulfate from a dilute solution of sulphate in the process of evaporation requires significant energy consumption (high energy consumption during the process of evaporation)that exceed the amount of energy to maintain normal water balance (which is of particular importance with increasing quality requirements for the primary the CSOs Mg-containing ore).

The process Skye in a closed system refers to a new process group, in this context called the regenerative processes of the atmospheric leaching (RAL). The basic concept is shown in figure 3.

Currently, this approach may be promising when carrying out processes in an open system: the highest energy costs associated with the melting process, and the minimum due process AL. However, to ensure an acceptable yield of extraction of Ni, when using this approach requires a high content of residual acid, especially when processing limonitic ores, which in turn leads to high costs of neutralization (low content of Ni in limonitic ores and its low reactivity in sulfate environment may limit the application of this method due to the low efficiency). If saprolite ore of high quality, which can be used as a neutralizing agent, this method becomes more economical. Currently, however, the economy largely depends on the quality of Ni and price on Ni and sulfur (S). If one of these symptoms is deflected in the negative side, this method becomes economically not profitable and thus is associated with high economic risk. And finally, the modern requirements of environmental protection n is focused against processes in an open system. If sea water is used, it is possible to slightly improve the efficiency of the separation L/S compared to pure water. However, when using sulfuric acid for leaching when the chloride content at the level of 20 g/l (typical for seawater), it is unlikely that in the neutralization process was formed hematite. There is a necessity for disposing of the residue and extremely high content of magnesium sulfate, which is disadvantageous, especially in humid climates.

The energy consumption for the HPAL process are unexpectedly low due to pre-process the pulsed heating. Due to the selectivity of this process in relation to Fe at high temperature (thermally induced deposition), the consumption of reagents is relatively low. However, due to the high investment cost is always largely depends on the consumption of acid and, therefore, the Mg content in the ore, which basically amounts to less than approximately 4% Mg, which means pure limonitic process. This process can only be used for limonitic ores high quality or enrich limonitic ores, processing of which requires low acid consumption.

In the process EPAL attempt to dispose of residual acid in the HPAL process, to enhance the yield of Ni from saprol is based ore and to reduce the cost of neutralization. However, the question of efficiency is, does the extra profit from processing saprolite ore the cost of adding additional acid. If the price of sulfur is satisfactory, additional acid can be used to leach even large quantities of saprolite. With increasing prices of sulfur in the diagram again include only the neutralization saprolite, which reduces the regeneration of Ni. Therefore, this process is associated with a lower risk compared to the AL process in an open system. However, you should consider investing in communication with the requirements of environmental protection.

Processes on the basis of chloride in a closed system (without introduction of the industry).

The process Jaduar

Atmospheric process chloride-acid leaching is shown in figure 4 (a process called Jaguar, developed by the canadian company for the exploration and development of Nickel deposits, Jaguar Nickel Inc.). This process includes a stage atmospheric leaching in hydrochloric acid solution containing a high initial level MgCl2. As described in Harris and others 2004, the activity of the proton increases significantly by increasing the concentration of magnesium chloride in the original solution. The leaching can be carried out in two stages, the first stage leached Ni and Co in the solution, and the second study is in control of the removal of Fe. Assume that an additional advantage of hydrolysis of Fe from the salt solution is a low water activity in saline solutions, which leads to faster reaction degidrirovaniya. In principle hematite can be formed at atmospheric temperature, otherwise (pure sulfate system) requires the use of an autoclave operated at much higher temperatures. After the recovery of valuable metals solution evaporated to provide the water balance and the resulting salt solution of magnesium chloride is fed into the recirculation system to the stage of leaching. The outlet stream is subjected to pyrohydrolysis and receive magnesia (which is partially directed to the recirculation system for internal neutralizing agent) and gaseous Hcl. HCl is then condensed and sent to a recycling system in the reactor to atmospheric leaching.

However, the economic problems of the process Jaguar become apparent due to the significant amount of energy spent in the process of evaporation of excess water from the concentrated solution of magnesium chloride before pyrohydrolysis and pyrohydrolysis, which is not comparable with the savings in regeneration of the reagents. The higher the quality of the magnesium material for leaching, the more water is spent on stage pyrogallol is in absolute units, that is, 1 kg of processed ore. Ultimately, when a high magnesium ore process Jaguar quickly becomes ineffective from the point of view of the water balance, because if you want to add an additional amount of water in the system to absorb more magnesium in solution, and the specified number again pariveda in the process of pyrohydrolysis. Like Jaguar "negative impact" on the water balance associated with high initial magnesium content in the ore, is observed in the process of Skye, but to a lesser extent (in this case, to prevent premature crystallization of the sulfate in the other system elements), but except that the added "extra" water will be distributed with relative efficiency in a multi-effect evaporator and only hydrated water from the magnesium sulfate will be affected at high temperature (expensive) stage of thermal decomposition. The lower the degree of hydration of the resulting magnesium sulfate, the lower the magnesium content in the raw material influences the rate of evaporation at high temperature stage of regeneration of the reagent (see figure 5). The steeper curve (figure 5), the less advanced regenerated Nickel (processing saprolite ore high quality) will increase the cost of the be evaporation of water during high temperature regeneration of the reagent.

Heat recovery is also an inefficient process and is complicated in reactors for pyrohydrolysis (Steinbach and Baerhold, 2002 and Adham and Lee, 2002). The process requires rare materials as hydrochloric acid condenses in the evaporator with heating waste heat in the heat exchange. In another embodiment, if hydrochloric acid is removed in the first stage, the observed loss of heat for regeneration. Another important factor is that some impurities, such as chlorides of calcium and sodium, are not pyrohydrolysis and the corresponding equivalent amount of chloride required to replace costly additional hydrochloric acid or magnesium chloride. It should also be noted that the overall efficiency of the reaction of pyrohydrolysis significantly below 100%.

Process properties Jaguar

- pyrohydrolysis is feasible at relatively low temperatures (~500°C), but the heat recovery difficult (high investment) and relatively ineffective

process Jaguar becomes uneconomical in the processing of laterite ores with high content of magnesium, that is, the specified process is intended only for processing limonitic ores,

impurities such as calcium and sodium, are not pyrohydrolysis, and there is a need to replace an equivalent amount the VA chloride for costly additional hydrochloric acid or magnesium chloride (excluding compensation inefficiency stage pyrohydrolysis).

The process Jaguar does not provide absorption of significant quantities of magnesium and is therefore incompatible in relation to common atmospheric processes using sulfates, such as the process Skye.

The Intec process

Recently was offered the chloride process (Moyes and others, 2005), intended to exclude pyrohydrolysis, i.e. for the regeneration of hydrochloric acid by precipitation of sulfates sulfuric acid. The principle of this process is the use of chemical precipitation and crystallization in the presence of cheap sulfuric acid for the regeneration of expensive hydrochloric acid instead of pyrohydrolysis. In the process Intec use cycle CaCl2/SO4(6).

The principle of this process is similar to the process Jaguar, but with the exception that only a drop of thread to remove iron and regeneration of Ni/Co carried out by adding lime. Then from the resulting solution precipitated magnesium in the presence of lime with the formation of magnesia (MgO). During all three operations mainly replacing chloride cation equivalent amount of calcium chloride. The total amount of hydrochloric acid consumed in the system, regenerate adding sulfuric acid, which leads to the precipitation of calcium sulfate (low rastvorimo the rd). The regenerated hydrochloric acid is returned via the recirculation system to the atmospheric leaching process. Sulphuric acid and lime, in turn, can be regenerated at the stage of thermal decomposition of calcium sulfate.

Process properties Intec

in this process get implemented (trademark) by-products of bassanite (CaSO4·1/2H2O) and magnesia (MgO), however, in the presence of this type of by-products having difficulty cleaning products

- unlikely is the possibility of cost-effective regeneration of sulphuric acid and lime method of thermal decomposition of calcium sulfate, the reaction of thermal decomposition occurs through the formation of intermediate products, the product of lime is refractory, and the process requires large amounts of energy,

- the higher the magnesium content in the ore raw materials, the greater the required sulphuric acid and lime, which leads to lower efficiency in the processing of saprolite ore.

Summary of the invention

In the present invention proposes a method of leaching the metal from the ore containing the specified metal, and this method lies in the fact that they are carrying out the following stages:

(a) leaching the ore in the presence of hydrochloric acid with the formation of rest the action of metal chloride in the leach solution,

(b) adding sulfuric acid and/or sulfur dioxide in the leach solution,

(C) regeneration of solid metal sulfate or sulfite of metal from the leach solution and

(d) regeneration of hydrochloric acid

and continuous transformation of at least part of the hydrochloric acid from the solution into the vapor phase.

Hydrochloric acid in the vapor phase can be absorbed and returned to the recirculation system to the step (a).

Hydrochloric acid is transformed into the vapor phase by heating the solution to its boiling point and is transferred using a carrier gas, such as air.

Before returning to the step (a) the leaching of hydrochloric acid in the vapor phase is distilled to remove water and concentration of hydrochloric acid.

After the leaching step in the leach solution add sulfuric acid and/or sulfur dioxide and simultaneously regenerate hydrochloric acid.

In another embodiment, sulfuric acid and/or sulfur dioxide is added to the leach solution during the leaching step, the leach solution are formed soluble chloride metal and solid metal sulfate or sulfite of metal, which are then recovered, and simultaneously regenerate the solution PI is estevadeordal acid with a high content of chloride ions and a low content of ions of sulfate or sulfite.

Metal sulfate or sulfite metal is characterized by the formula MeSOx·yH2O, where

Me denotes a metal, x is 3 or 4, and

y is 0 or more.

The source of the metal in the metal sulfate or sulfite metal is preferably iron ore.

The ore is preferably an oxide or silicate metal-containing ore, such as zinc oxide ore, laterite Nickel ore, such as Carolina or limonata ore or sulphide, titanium, or aluminum ore.

The precious metal leaching is chosen from the group comprising Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, CA, platinum group metals and gold.

In the invention features a method according to any of the points where the metal composition of the metal sulfate or sulfite metal is a metal which is leached, and the method further includes a step of decomposition of the metal sulfate or sulfite metal recovery metal. In another embodiment, the metal composition of the metal sulfate or metal sulfite is less valuable metal, not metal, which leached.

Brief description of drawings

Figure 1. The consumption and the cost of reagents for the HPAL process

Figure 2. Process model Skye

Figure 3. The General principle of regeneration in the process of ALP

Figure 4. Scheme of the process Jaguar

Figure 5. The need for high-temperature evaporation of water for the district is slichnih intermediate products

6. Scheme of the process Intec

7. The principle of the process ARNi

Fig. The General scheme of the process ARNi

Fig.9. Curves of Ni extraction after diagnostic leaching limonite ore in various chemical systems

Figure 10. Curves of joint extraction after diagnostic leaching limonite ore in various chemical systems

11. The activity of hydrogen ions in a solution of 0.5 mol./kg model HC1 depending on the concentration of magnesium chloride and temperature

Fig. Moralnosti free (non-associated) hydrogen ions depending on formal acidic moralnosti (1 mol/kg Hcl is equivalent to 0.5 mol/kg H2SO4and temperature in the presence of 2.5 mol/kg of Mg).

Fig. Rastvorimosti magnesium sulfate, depending on the temperature and acid concentration (simulation Aspen Plus, 2005).

Fig. Rastvorimosti magnesium sulfate, depending on the temperature and the initial concentration of chloride (modeling Aspen Plus, 2005).

Fig. The principle of extended process ARNi

Fig. Scheme of the process ARNi (extended version, including the evaporation of the hydrochloric acid)

Fig. Example enable the stage of evaporation of the hydrochloric acid in the main process ARNi

Fig. Experimental setup for measuring the composition of the vapor phase in equilibrium with brine

Fig. The measured data (t is his) and forecast data (planar graph) mass fraction of hydrochloric acid in the vapor phase in equilibrium with water vapor) for the system HCl-MgCl 2-H2O

Fig. The results of testing the absorption of sulfur dioxide in solution Fl3(2 mol/kg) and Hcl (0,5 mol/kg) at 105°C

Fig. An example schematic diagram of the evaporation of the hydrochloric acid

Fig. Extraction of Ni ferrous ore Jacare at low pulp density (low solids content, 5%) after 120 min of leaching in a solution of Hcl (1 mol/kg), but at different temperatures and concentrations of chloride Mg

Fig. The General principle of Anglo process Research Zn (ARZn 0)

Fig. The principle of Anglo Research Zn (ARZn 1), option 1

Fig. The kinetics of leaching under conditions of non-oxidative leaching in the presence of HCl at 90°C (+38-75 μm)

Fig. Laboratory setup for non-oxidizing atmospheric leaching

Fig. The results of leaching under conditions of non-oxidative leaching at low density pulp (low solids content, 2%) at 115°C for 120 minutes

Detailed description of embodiments of the present invention

In pending applications PCT/IB2005/003128 and PCT/IB2005/003136 included in this description in full as reference, describes a method for leaching one or more precious metals in a solution containing hydrochloric acid, from which the precious metal recovered in the form of solid sulphate or sulphite, when simultaneity is temporal regeneration of hydrochloric acid in solution. These related methods are called Anglo process Research Nickel (ARNi).

The process ARNi and the General scheme presented in Fig.7 and Fig, respectively. The process is a closed system for salt leaching under atmospheric conditions. The reagents required for stages of leaching and neutralization regenerate during operation. The efficiency of this method lies in the regeneration of the magnesium salt used leach solution with minimal removal of water using a low solubility of magnesium salts in the presence of high initial concentrations of magnesium chloride. This principle allows to obtain hydrochloric acid by direct addition of sulfuric acid and simultaneously extracts from the cycle of sulfate in the form of crystalline magnesium sulfate:

The cycle of reagents is closed when thermal decomposition of a specified crystalline magnesium sulfate to sulfur dioxide and magnesium oxide.

Magnesium oxide is partially used as a neutralizing agent in the process, while sulfur dioxide is used to produce sulfuric acid. The way ARNi allows you to maintain the concentration of hydrochloric acid chloride in the leach solution, without the need of pariva is their large quantities of water, want, for example, if stage pyrohydrolysis. All reagents are relatively inexpensive, thus there is the possibility to regenerate the basic reagent necessary for implementing the method.

The high level of chloride in the solution process ARNi provides higher reactivity of protons in comparison with other processes RAL, which is of special importance in the leaching limonitic ores (the most resistant to the action of chemical reagents). The above is shown in figure 9 and figure 10, for example, curves extraction of Ni and Co, respectively, after the diagnostic leaching limonite ore in various chemical systems. Chloride system is the most aggressive system leaching, especially if you increase the initial chloride concentration (in this case ~2 mol of chloride Mg on 1 kg of water). Such aggressiveness in turn leads to a low concentration of residual acid and thus reduce the amount of neutralizing agent. Obviously, the only way to compensate for the slow response leaching in sulfate system is the addition of excess acid. The beneficial effect of the added gaseous sulfur dioxide is explained due to the resilience of decomposition of oxide is i.i.d. minerals, first of all materials that contain the bulk of Co. These more aggressive leaching conditions in chloride environment can be explained by two reasons:

the activity of hydrogen ions increases with increasing the initial concentration of chloride ions (11),

- moralnosti hydrogen ions is reduced in the presence of sulfate due to the formation of bisulfate ions (link H-chloride weaker than the bond N-sulfate, Fig).

With regard to water balance, all three processes RAL (closed system) are characterized by almost the same as the requirements for energy consumption for raw materials - limonite ore, which effectively addresses when using a multi-effect evaporator. However, if the Mg content in the raw material increases, the energy consumption during the process of evaporation increase in pure sulfate (add an extra amount of water to prevent crystallization of sulfate and chloride (add an extra amount of water to maintain the chloride of Mg in solution at the stage of pyrohydrolysis) systems. In addition, in the process Jaguar produce large amount of water in the stream (in absolute units, i.e. kg regenerated Ni)coming on expensive high-temperature stage (pyrohydrolysis), while in the process ARNi low number of hydration water in salts PP is no need of high temperature evaporation during processing of raw ore, contains Mg.

From the point of view of environmental protection, believe in pure sulfate system is formed sulfate-hydroxide hydroxide of Fe and Fe, which are unacceptable for release into the environment, especially in areas with rainy climate. This process leads to a significant loss of sulfate from the cycle, without regard to hardware problems. If you use the precipitation of goethite, which requires special operating conditions, you can expect a significant loss of Ni and Co (goethite is a carrier that enhances the quality of Ni and Co in the natural primary layers, i.e. in the process of lateralization). Hematite, in turn, is rapidly formed in systems with a high content of chloride is stable in ambient conditions and does not absorb Ni and Co in the crystal structure. It is also known that the hematite is characterized by the improved characteristics of sedimentation and filtration, as well as the relatively low moisture content. It can also be used as an industrial pigment, for example, in the manufacture of brick.

Impurities of alkali and other metals such as Na and CA, are formed in pure chloride system in the process of deposition, which leads to some loss of chloride and that the inability of these metals to be pyrohydrolysis. These impurities formed during ARNi, can UD is pouring deleting Na in the form of jarosite and calcium in the form of gypsum. Indeed, one can use the reaction of formation of sodium jarosite, in order to avoid the loss of chloride in the loop, using relatively inexpensive reagents, sulfur and sodium chloride.

As indicated above, when using pure sulfate closed loop (Skye) is required to take into account the levels of solubility in the operation of the various nodes of the process, especially when adding or removing water (an expensive operation). Use the temperature rise, but it is expected that this temperature increase is significantly less effective in connection with the modern requirements to the use of atmospheric pressure and to minimize the capacity during heating/cooling. Mixed salt system selected for the process ARNi, opens new perspectives, that is, a low-cost alternative process. At the stage of crystallization add the primary source of sulfate (sulfuric acid), and thus provide a common ion effect and precipitation of magnesium sulfate. Naturally, at this stage ion gitonia is in a state of maximum activity, which leads to undesirable effects on the solubility, that is, to increase solubility, likely due to the formation of bisulfate ion (HSO4-) (Fig). Offered a high level of operating flexibility (drop what I use water for these purposes) by an appropriate system integration and therefore, selection of the levels of chloride and sulfate in the mould. Initial concentration Mg provides a greater degree of flexibility compared with pure sulfate system (Fig). The most expedient is to supply the most concentrated operational flow of chloride and sulfate, i.e. saturated leach solution (PLS) and flow after evaporation in the mold. In addition, at the stage of evaporation is generally formed of a supersaturated solution of sulphate Mg, to compensate for even greater extent the above inefficiencies.

From the point of view of economy and management, the control of the solubility of the sulphates in the mould is a very important factor. The main reason for such control is necessary to avoid a critical situation where you need to control the levels of solubility in the mould to ensure the removal of sulfate, and the aftertreatment system (which is going end balance), which is required to prevent the removal of sulfate.

In the present invention proposes a method of control in the system due to evaporation of at least part of the formed hydrochloric acid. First of all a certain amount of hydrochloric acid evaporated, to avoid adding to the water to control the relative levels of solubility in the system, and also to provide a sufficient amount of hydrochloric acid in the circulation system to return to the stage leaching, i.e. to compensate for the variability of the composition of the raw ore.

In the present invention proposes a method of leaching precious metal from the ore, which provides optimized reagents and energy. The main reagent, i.e. HCl, regenerate, this eliminates the need to neutralize the solution before crystallization, obtained after leaching, or need to add in the system with fresh reagents. The effectiveness of this approach increases with the use of concentrated salt solutions, which provides additional advantages: 1) education digidratirovannogo crystalline product, i.e. the reduction of energy consumption by thermal decomposition (regeneration reagents), 2) education digidrirovanny stable products of the hydrolysis of Fe (such as hematite) at ambient temperature, 3) fast kinetics of leaching due to high activity of protons and 4) leaching and regeneration of important by-products (e.g., Pb, Ag).

Valuable metal is leached from the metal-containing material, which is a sulfide or resolvedname material. For example, the material is a metal oxide ore, Taco is as zinc oxide ore, lateritic Nickel ore, such as Carolina or limonata ore, the sulfide ore, aluminum ore and titanium ore. First, the precious metal forms a first soluble metal chloride, then a solid sulfate or sulfite.

Precious metals are usually chosen from the group comprising Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, CA, platinum group metals and gold.

The solution of chloride of the metal is an alkaline solution and/or metal sulfate is the sulfate of an alkali metal.

Sulfuric acid is usually at a concentration of at least 30% (e.g., approximately 98%) and/or sulfur dioxide is added to the solution containing the leached precious metal, you get a solid sulfate or sulfite of metal, which is then recovered. In this case, for the regeneration of an expensive reagent (hydrochloric acid) use relatively inexpensive reagent (sulphuric acid or sulphur dioxide), which leads to significant savings.

However, thermodynamic and kinetic parameters of chemical reactions may become more negative as they regenerate a significant amount of hydrochloric acid. In the present invention focused on this factor and it is suggested the way the controlled removal of hydrochloric acid from the solution in the reactor at a GTG is the NCA (the process of evaporation and absorption, the distillation and condensation and/or distillation of at least a part of hydrochloric acid with the subsequent direction of flow of the remote parts of hydrochloric acid into the circulation system and in the system process.

Solid metal sulfate or solid metal sulfite is usually characterized by the formula:

MeSOx·yH2O,

where Me denotes a metal,

x is 3 or 4, and

y is 0 or more, for example, from 0 to 3 and more preferably 0 or 1.

The concentration of metal chloride is usually chosen to achieve the following objectives:

a positive effect on the leaching process, as described, for example, to process Jaguar,

ensure leaching of the metal from the ore, not exceeding the solubility of metal chloride in the conditions of leaching (in another embodiment, water is added to avoid the loss of chloride in the solid phase),

accelerating the deposition of the corresponding sulfate or sulfite, i.e. the concentration of the metal should be excessive in relation to the solubility of the sulfate or sulfite,

impact on the degree of hydration phase precipitate sulfate or sulfite to the degree of hydration of the salts obtained was lower compared to the possible degree of hydration of the salts obtained from dilute solution of sulphate or sulphite, and

not to exceed the limits of solubility required on other stud the s process (in this case require different operating temperatures at various stages of the process, in another embodiment, in order not to exceed the limits of solubility, at certain stages of the process, water is added),

high rate of evaporation of at least part of the formed hydrochloric acid, which suppresses the solubility of sulfate and, thus, supported the balance of hydrochloric acid in the entire system.

The initial concentration of hydrochloric acid is chosen in such a way as to ensure a high degree of leaching of the metal from the ore and at the same time to comply with the absorption of acid.

Sulfuric acid and/or sulfur dioxide is usually added to the solution in sufficient quantity that the concentration of the regenerated hydrochloric acid was higher than the azeotrope concentration, which is determined by the solubility of metal chloride or chloride of alkali metal in comparison with the concentration of hydrochloric acid, which is formed after deposition in the form of sulfate or sulfite. Saline solution is characterized by a low initial concentration of metal chloride, which is added with an additional concentration of metal chloride in the course of the leaching process. Preferably the amount of added sulfuric acid or sulfur dioxide in the above solution should slightly exceed the quantity required to compensate the oxygen is the radio of the acid-salt solution to the initial value. In other words, the initial concentration of metal chloride should not be lowered in the process of crystallization of the corresponding sulfate or sulfite. In another embodiment, the solution after leaching into fractions, and only one of them is used for the deposition of sulfate or sulfite, while deposition occurs depending on the solubility, while the initial level of chloride does not change in the remaining untreated fractions.

The method also includes the stage of crystallization to obtain crystals of the metal sulfate or sulfite of metal with low content of water of hydration. In another embodiment, to reduce the cost of these reagents for the purpose of such chemical is crystallized using the crystallization by evaporation (within or with a small excess of standard water balance). This option is possible due to the simultaneous effect of the initial concentration of salt in the solution on the degree of deposition of salts in the process of evaporation of water. Moreover, the joint deposition of Ni in the crystal structure of magnesium salts usually prevails during crystallization at low temperatures. The tendency of Ni in co-crystallization is significantly reduced when the chemical crystallization at a temperature close to the boiling temperature of the solution at atmospheric pressure. If POS is but such loss of valuable Nickel from the system are unacceptable, in the present invention is proposed to stage chemical crystallization in a series of successive stages. This method allows monitoring of working conditions, for example, in favor crystallization contaminated salt (Ni) at the initial stage in the mould, but at a late stage in favor of the formation of relatively pure salt. Contaminated salt can be returned to the circulation system and in the system process. Pure salt can be used as commercial products and subjected to thermal decomposition with the formation of a metal oxide, which is also used as a commercial product, as well as sulfur dioxide, sulfur trioxide, or mixtures thereof, and/or salt re-dissolved in the solution of sulfate and then subjected to electrolysis.

One or more precious metals, such as cobalt, Nickel, platinum group metals, gold, silver and/or copper is selectively removed from the solution before the stage of formation of sulfate or sulfite of metal.

Iron and/or other residual impurities resulting from the solubilization of ore, partially or completely removed from the leach solution, for example, using solvent extraction with subsequent pyrohydrolysis or hydrolysis.

The metal in the composition is of lipata or sulfite metal is a precious metal, and method generally includes a step of decomposition of the sulfate of the metal for the regeneration of a precious metal.

In another embodiment, the metal composition of the sulfate or sulfite metal is less valuable, such as magnesium, and the precious metal recovered independently of the metal salt formed by the addition of sulfuric acid or sulfur dioxide.

The sulfate or sulfite metal handle to release sulfur dioxide.

The method is not necessarily limited temperature intervals, provided that the solubility of the metal sulfate or sulfite metal is much lower than the solubility of the corresponding chloride. However, the leaching mainly carried out at a temperature from room temperature up to the boiling point of the solution, and the stage of crystallization of the sulfate or sulfite is usually carried out at a temperature at which the difference in solubility is the maximum.

Before adding sulfur dioxide magnesium is not necessarily removed from the leach solution and replace with the other metal cation, such as calcium, lead or barium. After removal of the magnesium salt of the metal, obrazowania adding sulfur dioxide, an intermediate sulfite or sulfate such as calcium sulfate, calcium sulfite, sulfate of lead, lead sulfite, barium sulfate or barium sulfite. Intermediate sulfate or sulfite is subjected to term the economic decay, the formation of a metal oxide such as calcium oxide, and sulfur dioxide. Sulfur dioxide is used again to vysalivaniya sulfate or sulfite from the leach solution and regeneration of hydrochloric acid.

Other objects of the present invention include the following characteristics:

the concentration of hydrochloric acid is regenerated in a salt solution of chloride of non-ferrous metal,

the resulting solution contains a high concentration of chloride ions and a low concentration of ions of sulfate or sulfite,

the leaching process is carried out in chloride environment adding gaseous sulfur dioxide or sulfuric acid,

metal, such as zinc or magnesium, regenerate chloride salt solution in the form of a salt with a small amount of hydration water, which is subjected to thermal decomposition, re-dissolve in the sulfate solution and electrolysis directly from the solution obtained, or used in the form of commercial products, in the form of sulfate or sulfite, or after thermal decomposition to oxide,

high pressure vapor of hydrochloric acid can be used to move acid from the solution into the vapor phase and, thus, to control for the chemical reaction during the operation of a particular host system.

This izopet the tion described in detail below in several examples. These examples do not limit the nature or scope of the invention.

Bisulfide ore

In the first embodiment, the present invention proposes a method of leaching of magnesium, and at least a certain amount of valuable Nickel and cobalt from a source of hydrochloric acid from bisulfide ores, such as laterite ore, limonite, oxide ore and/or silicate saprolite. Basic leaching agent is the hydronium ion formed in the initial chloride environment, the presence of which is associated with the presence of their impurities, primarily of magnesium chloride.

Pererabotka bisulfide materials are described in detail below on the example of Nickel laterite ore as bisulfide material. Specialists in the art it is obvious that a similar method can be used to process other bisulfide materials, such as silicates of zinc, bauxite, etc. Used laterite is also an example in which the valuable metal is not metal, which is used at the stage of regeneration of the concentration of chloride salt solution. Schematic diagram of the process shown in Fig.

Regeneration of hydrochloric acid and extraction of magnesium, as described above, is not associated with the removal of excess water in the process of evaporation, as was first removed Ute magnesium in the deposition, instead of the electrolyte solution of magnesium chloride (as in method Jaguar). However, in another embodiment, the crystallization in the process of evaporation (within or with a small excess of standard water balance) can be used to reduce the cost of reagents at the stage of chemical crystallization. This option is possible due to the simultaneous effect of the initial concentration of the salt solution on the degree of deposition of salts in the process of evaporation of water.

The concentration of the acid salt solution of magnesium chloride after leaching regenerate adding sulfuric acid or gaseous sulfur dioxide, resulting precipitated sulphate or sulphite magnesium with a low degree of hydration and is formed in the solution of hydrochloric acid.

The residue after leaching of laterite process at the next stage of leaching, in order to maximize the yield of recovery of Nickel and cobalt.

In the case of sulfate experimental data Linke and Seidell (1965) suggests that keseric (monohydrate magnesium sulfate) is the preferred product of crystallization at a high temperature (approximately 100°C), which allows to reduce to the minimum energy required for ignition with the formation of magnesium (which is partially directed to the recirculation system as neutralizes the th agent) and sulfur dioxide. A simplified reaction scheme is shown below:

In this way we obtain a crystalline product with a total chloride content less than 0.01%. It is established that the joint crystallization of Ni in the crystal structure of kieserite reduced to a minimum holding specified reaction at a temperature close to the boiling temperature of the solution at atmospheric pressure or at elevated temperature and pressure). It is assumed that using this method you can get magnesium oxide with high purity, which can be used as a commercial product and/or as a neutralizing agent. In another embodiment, if the loss of Nickel are invalid, the Nickel is removed before crystallization using chemical methods, for example, ion exchange, solvent extraction, diffusion saturation (cementing), deposition, etc. in Addition, relatively expensive regenerate hydrochloric acid using sulfuric acid or sulfur dioxide, which are relatively cheap and readily available reagents. A promising solution to this problem is multi-stage method of conducting crystallization. Working conditions can be controlled so that first to ensure the destruction of the foundations of the CSOs amount of Nickel in the composition of the contaminated magnesium sulfate, and then in the later stages of crystallization, to ensure formation of pure salt, when the content of Nickel in solution is depleted.

A pair of Fe3+/Fe2+in the salt system plays an extremely important role in the direct use of sulfur dioxide to precipitate the sulfate or sulfite. In the absence of ferric ion, the ability of a solution to absorb sulfur dioxide is extremely small in solutions with high initial salt concentration, i.e. the absorption in this system ineffective. However, in the presence of ferric ions is direct absorption of gas in solution due to the reduction reaction of trivalent iron to divalent. This reaction is accompanied by changes in the solution, which in turn lead to preferred salting out sulfate or magnesium sulfite. An important aspect of the above chemical reaction is the tendency of a decrease in the efficiency of the reaction of 3 with an increase in the number of the formed hydrochloric acid over time. This phenomenon occurs for two reasons. First, the specificity of the chemical reaction may change as increasing the amount of hydrochloric acid due to the formation of bisulfate ion or bisulfite (HSO4-, SO3-). Eventually overzeese the solubility of the salt, as the ion concentration of sulfate or sulfite effectively reduced during the formation of the complex ion of gerania. Secondly, the kinetics of the precipitation reaction is slowed down considerably, especially when using sulfur dioxide as a reactant, the reaction between ferric ion and the sulfur dioxide becomes kinetically limited.

Fortunately, hydrochloric acid is characterized by a high vapor pressure, which allows you to remove it (directly or indirectly) when Stripping (evaporation), for example, with steam. In another embodiment, it is possible to use a gas such as air or nitrogen. One stripped off hydrochloric acid then can be absorbed directly in the working solution at a different stage of the process, or you can condense with heat and then return it to another stage of the process. In yet another embodiment, hydrochloric acid can be driven away from the salt solution. Such removal of hydrochloric acid (and its subsequent return to the recirculation system to another stage of the process) can be used to provide the required degree of reaction crystallization. Thus, the specified property hydrochloric acid to effectively jump into the vapor phase, can be used to compensate for the inefficiency of the reaction crystallization.

The method according to N. the present invention, described in this context, shown in Fig and based on the low solubility of magnesium sulfate in solution in the presence of large quantities of magnesium chloride in the original solution. Adding sulfuric acid, sulfur dioxide, sulfur trioxide, or mixtures thereof in the rich leach solution (PLS) leads to the precipitation of sulfate with the simultaneous regeneration of hydrochloric acid, which is returned to the recirculation system for reuse at the stage of leaching at atmospheric conditions. On Fig shows the proposed change in the solubility of magnesium sulfate with increasing initial content of chloride (simulation using commercial software AspenPlus).

Precipitated magnesium sulfate or magnesium sulfite in turn undergoes thermal decomposition with the formation of magnesia (for use as an internal neutralizing agent) and gaseous sulfur dioxide. Gaseous sulfur dioxide is transformed into sulfuric acid on the device for producing acid and re-directed to the recirculation system on stage chemical precipitation of sulfate.

In addition to temperature changes and peremesheniya water, an important variable when the integration process is the concentration of the salt solution. Conversely, in the process based on sulfate, that is ω as the process Skye, degrees of freedom are only the temperature and movement of water. In this case, it is necessary to add large quantities of water to prevent crystallization in the stream, and, therefore, there is a need for removal of large quantities of water (kg processed ore) to achieve the required level of crystallization by evaporation. The importance of such a "negative" effect of water increases significantly with increasing magnesium content in the ore. On the contrary, in the present invention is proposed stage chemical crystallization, and not the process of evaporation, thus the water balance does not depend on the variability of the content of magnesium in the ore raw materials. In addition, due to the high initial concentration of salt in the method according to the present invention occurs simultaneous effect in the process of evaporation, which is simply based on the water balance, which leads to the deposition of larger amounts of magnesium sulfate or magnesium sulfite. This effect compensates for the inefficiency of chemical vapor deposition (due to undesirable solubility), without the need to significantly increase the cost of energy of steam (under abnormal water balance). In addition, the high initial concentration of salt promotes the evaporation of the hydrochloric acid that provides an introduction is another degree of freedom in the control system. Thus, the system based on the mixed chloride-sulphate electrolyte increases the versatility of the process in comparison with a simple process in a closed system on the basis of sulfate (method Skye).

In this case, suppress the solubility of the sulfate or sulfite in the system while maintaining a high initial concentration of chloride in the system. At the same time, a high initial concentration of chloride leads to high activity of protons and low water activity. Figure 11 shows a three-dimensional graph of the activity of protons from the temperature and concentration of magnesium chloride.

Schematic diagram of the process according to the invention showing on Fig. Recirculation system reactor under atmospheric conditions provides maximum stay of hydrochloric acid for interaction and minimizes requirements for neutralization (the inner content of Mg in a recirculation system per unit of processed ore) in the system. Neutralize only the outlet stream for the hydrolysis of Fe with subsequent regeneration of Ni and Co in the precipitation of hydroxides. After neutralization using a single stage evaporation to maintain water balance. Chemical crystallization of the splitting the flow of the main recirculation system makes it possible to regenerate the equivalent consumption of chlorotoluron the th acid and to compensate for losses from the system. The precipitated sulfate is calcined with the formation of gaseous SO2and magnesia. Gaseous SO2turn into sulfuric acid in the plant for production of acid and returned to the recirculation system in the mould, at the same time as part of magnesia return in the recirculation system for internal neutralization. Excess magnesium can be used as a commercial product. Part hydrochloric acid and evaporated to provide the required amount of hydrochloric acid in a recirculation system for leaching, i.e. to compensate for inefficient solubility in the mould.

On Fig shows the advantage of using the Stripping of hydrochloric acid in the integrated system. In the case of operation of host chemical crystallization hydrochloric acid is removed from the salt solution to activate the deposition reaction, i.e. to compensate for the inefficiency and slow kinetics of formation of the ion of gitonia during the deposition reaction.

Evaporation of hydrochloric acid

Determination of the degree of evaporation of the hydrochloric acid is extremely important (Fig) and includes the following stages:

1) get the salt solution by dissolving various salts and solutions in water at previously defined is concentratie in units of moralnosti (moles of the substance/kg of water)

2) measure the density of the solution at 25°C and a sample is taken for chemical analysis,

3) then a certain amount of solution (~2 kg) is transferred into the main reactor,

4) the solution is heated (bath with circulating oil to the boiling temperature in the absence of any gas flow,

5) then through the specified solution is passed a stream of carrier gas (nitrogen) (100 ml/min)to transfer the vaporous mixture in the reactor-trap through the condenser,

6) reactor-trap (continuously cooled in an ice bath and circulating chilled water contains a certain amount of water (~500 g)to minimize evaporation of the hydrochloric acid in the atmosphere

7) after a certain time after the preparation of the experiment (which must be minimized to avoid too significant change in the composition of the initial solution in the course of the experiment, the flow of carrier gas off, then measure the boiling point and the heat shut off,

8) from the main reactor drain the solution through the condenser to the reactor drain (continuously cooled), the specified reactor equipped with a reflux condenser to minimize loss of hydrochloric acid in the environment

9) record the exact mass of the residual solutions in the main reactor, the reactor is trapped and the reactor to drain, if RA is the difference in total mass between the sum of these masses and the initial mass of solution) significantly greater than 1 g, the experiment is repeated,

10) finally, measure the density of solutions in each of these three reactors and draw samples for chemical analysis.

The metal content in the solution was determined quantitatively spectrometer ICP-OES (inductively coupled plasma with optical emission detection), and the acid content and the total content of chloride was determined by the method of chemical analysis in solution.

The results are shown in Fig and testify to the advantage of the process in the presence of a high initial concentration of chloride. Blue circles indicated the fraction of Hcl in equilibrium with the solution in the absence of iron, yellow and red squares indicate the measured data in the presence of 1 and 2 moles/kg Fel3, respectively. Black triangles denote the solutions containing 2 mol/kg Hcl, 2 mol/kg Fl3and 1 mol/kg and MgSO4and various initial concentrations of MgCl2from 2 to 4 moles/kg First of all it is important to note that the presence of sulfate ion in no way does not affect the volatility of Hcl, and thus opens the possibility of using technology evaporation to control the acid in the primary leach solution and at the same time to suppress the solubility of sulfate in the mould.

Join scheme evaporation of the hydrochloric acid from the absorption of deoxidizer

Evaporation of the hydrochloric acid can also be used in case of sulphur dioxide directly absorb for the regeneration of an equivalent amount of acid, there's no need to use the plants for acid.

At the stage of regeneration of the acid can be used catalyst or oxidizing agent, such as iron (3+), as a carrier/sorbent for gaseous sulfur dioxide. The main amount of iron goes into solution in the form of Fe(3+) at the stage of leaching of the ore, as, for example, by leaching of oxide ores such as Nickel limonite. However, if the principal amount of iron goes into solution in the form of Fe(2+), for oxidation of ferrous iron to ferric iron required oxidant (such as oxygen or a gaseous mixture containing oxygen and sulphur dioxide).

This is followed by a stage of regeneration of acid, in which the absorption of sulfur dioxide is accompanied by a release of sulfuric acid in the solution:

In a mixed chloride/sulphate system, the difference in solubility of metal chloride and sulfate of the metal used for the regeneration of the equivalent of hydrochloric acid consumed during leaching. Leaching of magnesium from laterite oxide ores flows following the reaction the Oia:

Below is a General scheme of the reaction at the stage of regeneration of the acid:

Similar reactions occur and in the leaching of other metals that can be used when developing a method of regeneration of an equivalent amount of hydrochloric acid consumed in the leaching step. The precipitated salt (MgSO4·H2O, as described above in the example, are subjected to thermal decomposition to regenerate an equivalent amount of gaseous sulfur dioxide, providing, thus, a fully self-sustaining process. In another embodiment, the sulfur (or another cheap source of sulfur) burn in air with the formation of gaseous sulfur dioxide, which is used directly, as described above, there is eliminated the necessity of turning gas into sulfuric acid on the costly device for producing sulfuric acid. On Fig presents the results of tests conducted to confirm the possibility of direct absorption of sulfur dioxide into a solution of trivalent iron. Observed the formation of a stoichiometric amount of hydrochloric acid in relation to the number of added sulfur oxide. Thus, it is possible to ensure the deposition of sulfate Mg in the absorption of gaseous sulfur dioxide and at the same time to ensure the evaporation of part of the formed hydrochloric acid for controlling solubility phase crystallization in the column of the mold. On Fig shows an example of a possible scheme of merger stages of absorption of sulfur dioxide and evaporation of the hydrochloric acid in consecutive columns, and at the same time, to ensure formation of a crystalline precipitate with a high degree of purity.

An example of using evaporation to overcome the inefficiencies in the leaching step

On Fig shows the results of tests on leaching, which was carried out at various concentrations of magnesium chloride. Obviously, the initial concentration of magnesium should be limited because of its negative impact on the primary leaching, if you get a solution with saturation of more than 60% (compared with saturation in pure water), especially at higher temperatures leaching. Assume that the slow kinetics of leaching at high levels of magnesium are associated with localized saturation of magnesium salts on the phase boundary particle/solution that leads to the formation of passive films on the surface newselected particles. To avoid such a negative effect on the kinetics of leaching, it is possible to reduce the level of salt in the solution due to the evaporation of part of hydrochloric acid and its return to the recirculating system through leaching. Using two opposite effects, which provide Janie on the economy of the whole process: the higher the initial concentration of chloride, the faster it evaporates hydrochloric acid. However, the higher the level of magnesium chloride, the greater slows down the kinetics of leaching. Thus, for a given level of chloride required for optimal evaporation rate, and the additional advantage is realized by using an effective method of evaporation and can be used to control the system, i.e. it can be used to offset temporary imbalances in the mould due to unexpected changes in the composition of the solution, for example, due to the variability of the composition of the raw ore or loss of sulfate from the system.

Sulfide ore

The second variant implementation of the present invention refers to the use of hydrochloric acid (chloride) for oxidative or non-oxidative leaching of sulfide concentrates, such as zinc-containing ore, as described below. Despite the fact that the use of non-oxidizing processes for the regeneration of non-ferrous metals from sulfide concentrates is not in itself new (sulphate environment: S C Copper Process, Kawulka and others (1978), chloride environment: Molleman and others (1998)), method of regenerating acid is not described in the art. Non-oxidative method for leaching salt solutions with a high concentration in combination with an integrated stage regeneration key is lots accompanied by evaporation of the hydrochloric acid, also not described in this technical field.

Valuable non-ferrous metals, such as zinc leached from the sulfide concentrates in the original solution of hydrochloric acid. Leached non-ferrous metal obtained as a commercial product. The kinetics of leaching is rapid and metals such as copper, to form a solid phase (such as CuxS) and regenerate from the tail fractions if necessary, using the oxidative leaching process. An additional advantage of the non-oxidative conditions is the possibility of regeneration of elemental sulfur using a standard Claus process (oil/petrochemical industry).

Environment for leaching containing chlorotoluron acid, used to solubilize the securities of zinc sulfide material (under a non-oxidative recovery), and then the zinc is removed in the form of a crystalline salt at the stage of regeneration of the acid. For the regeneration of the zinc sulfate does not require neutralization with a saturated solution of leaching, and zinc sulfate regenerate adding sulfuric acid. The precipitated sulfate is in the form of a monohydrate, and not in the form of uranyl (as would be expected according to experts in the art). what this form is preferred if the sulfate is converted into the oxide, as this provides considerable savings in energy consumption compared to uranyl. Impurities such as iron, is removed by hydrolysis after neutralization of the excess acid returned from the recirculation system of calcined zinc oxide. In another embodiment, since hydrochloric acid is characterized by a high vapor pressure, even in mixed chloride-sulfate salt system, part hydrochloric systems can be pressed (was evaporated to) from phase solution into the vapor phase (directly or indirectly) with steam or gas, or can be removed by distillation. Remote hydrochloric acid is then further distilled (if necessary), condense or directly absorb in the working solution and sent to a recycling system at the primary stage of leaching.

The method is based on a new principle of regeneration, that is, the return of the leaching agent and neutralizing agent in the recirculation system process.

Preliminary estimates of the balance of mass/energy showed a significant advantage of this principle compared to the standard processing of sulfide ores.

The most important are the following factors:

As a concentrate, you can use the purified concentrate or preferably m is cleared her (rough) concentrate (higher degree of extraction of precious metals) or even crude ore,

non - oxidative leaching is carried out at any desired concentration of Hcl, while maintaining the overall level of chloride in the rest of the system, but preferably the leaching is carried out only with a slight excess of Hcl, thus, reduced requirements for neutralization outlet flow from the system (removal of impurities), you can even use a counter-current configuration of the leaching process to ensure a high degree of extraction of zinc, but low residual concentration of acid,

Si re-deposited in the form of CuxS at the stage of leaching at atmospheric pressure, i.e. if necessary, the copper is recovered from the residue of waste rock, if it justifies the cost,

- Pb leached from the system in the form of chloride complexes and precipitate in the mould in the form of sulphate. PbO formed at the stage of thermal decomposition, effectively recovered from the residue obtained at the stage of re-leaching of ZnO in the form of purified salt PbSO4,

- ZnSO4·H2O is formed in the mold by adding H2SO4in chloride solution due to differences in the solubility of sulfate and chloride: ZnCl2+H2SO4+H2O→ZnSO4·H2O+2hcl.

The main advantage of this reaction is the property of the original salt dissolve the and to bind free water, this created digidrirovannye salt (less than 1 mol H2O 1 mol of zinc), which significantly reduces the energy consumption at the stage of decomposition compared to salts comprising a large number of hydration water, such as ZnSO4·6H2O,

- Part of the resulting hydrochloric acid in the chemical process of crystallization can be continuously removed by Stripping (evaporation) with steam or gas (directly or indirectly) or distillation, in order to maintain the driving force for the reaction crystallization/precipitation. Such remote hydrochloric acid is then directed into the recirculation system process

- Above the stage crystallization and thermal decomposition are in stoichiometric balance and does not require additional add H2SO4(except for the analysis of products obtained in an industrial setting),

- Part of the salt solution divert from the main thread (before crystallization) to limit the accumulation of iron in the source system. The proportion of zinc oxide (obtained at the stage of thermal decomposition) enters the recirculation system to neutralize the free acid in otodrom stream containing impurities, which provides saturation of precious metals (silver, Nickel, cobalt, cadmium) zinc dust is Yu before removing iron,

The hydrolysis of iron is carried out at atmospheric pressure or under reduced pressure in an autoclave, by hematite and/or goethite. Another advantage of the salt solution with high concentration is extremely small content of free water, which, in turn, provides the dehydration of oxides/hydroxides of iron and the precipitation of hematite at much lower temperatures compared to the standard sulphate systems,

- The main mass of zinc oxide (excluding run-off stream to neutralize) arrives at the stage of re-leach, on which the oxide is dissolved in the presence of sulfuric acid in the anolyte flowing from the electrolysis system. Acid is in stoichiometric equilibrium and does not require adding more acid or neutralizing agent (except for the analysis of products obtained in an industrial setting),

- Part of the precipitated zinc sulfate can be dissolved in the wash water and send the system for the standard solvent extraction/electrowinning where the required quantity of metallic zinc regenerate and stoichiometric equivalent amount of sulfuric acid return (in a mixture with unreacted zinc sulfate) at the point of crystallization,

- Throughout the system there is no need to bend the om thread, or you want to take only a small amount of solution, since sodium sulfate is accumulated before saturation and deposited in the most concentrated section of the system

- Because there is no need for otodrom flow or need to take only a small amount of solution, the removal of water is achieved by using a multi-effect evaporator,

At the stage of crystallization is a low solubility product, sulfate or sulfite of nonferrous metal, such as zinc, in the original chloride salt solution to remove leached precious metals from solution. Crystals of sulfate or sulfite contain a minor amount of water of hydration and is suitable for thermal decomposition with the formation of oxide (for use as an internal neutralizing agent), which can be used as a commercial product or part which can be dissolved in sulfuric acid (forming during electrolysis) and used for direct electrolysis of the metal (see Fig). Regeneration of hydrochloric acid and extraction of non-ferrous metal, such as zinc, as described above, is not associated with the removal of excess water in the process of evaporation, because the metal is obtained from the crystalline cake with low water content and hydration water. However, due to the fact that at the stage of thermal decomposition still takes a lot of energy, in which the version of the core schema of the process, you should consider re-dissolution of zinc sulfate in the wash water and the regeneration of the metal by the method of standard solvent extraction/electrowinning. The schematic is shown in Fig.

The most optimal configuration process may include the hybrid main method (ARZn 0) and the first option (ARZn 1), regeneration of the principal amount of Zn methods crystallization/re-dissolution/solvent extraction/electrowinning and decay only part of the precipitated zinc sulfate, to meet the requirements of internal neutralization. An important object of the present invention based on significant difference of solubility of zinc in suspension. A simplified reaction scheme is shown below:

Crystalline product containing less than 0.01% of the total chloride, get described in the application of the method to illustrate the effectiveness of this technology, i.e. to obtain zinc oxide high purity as a commercial product (proportional to the number used as the internal neutralizing agent) or for re-dissolution of zinc oxide in sulfuric acid (coming after electrolysis) and direct electrolysis of zinc metal from the resulting solution. Also the regeneration of relatively expensive hydrochloric acid with the use of relatively cheap and available reagent, i.e. sulphuric acid.

Similarly bisulfide examples of evaporation of Brazauskas the hydrochloric acid is of great importance for effective control system, that is, to offset temporary imbalances in the system and, for example, to compensate for the loss of sulfate from the system.

An example of the importance of the stage of evaporation of part of the hydrochloric acid from the mould

Favorable kinetics of leaching is achieved by processing the original rough concentrate, which allows use of the method according to the invention for leaching of valuable metals such as zinc, silver and lead from sulphide ores. The most important is fast (less than 1 h) kinetics of leaching at a temperature of 85°C in 4 M solution of hydrochloric acid (Fig). The experimental scheme is shown in Fig.

Subsequent analysis (Fig) showed a similar (compared with the behavior of laterite ore), but more significant slowing of the kinetics of leaching, if the leaching was carried out at a high initial concentration of metal. And again the reason for this phenomenon is the deposition of saturated salts on newselected the particles, particularly if the initial salt concentration is high. In another embodiment, the displacement reaction 6 in the direction of the initial reagents becomes more significant when a high concentration of zinc is predominant in the leach solution.

ZnS+2H+⇔Zn2++H2S

Consequently, the evaporation of a certain amount of chloride is ogorodnoi acid from the mold, in order to provide a sufficient amount of acid at a relatively low salt concentration, at the stage of non-oxidative leaching.

Metallurgical analysis

Laboratory simulation includes 4 stages, i.e. leaching, crystallization, thermal decomposition and re-leaching of calcined zinc oxide. Evaluate the distribution system the following items (lower limit of detection was 10 ppm):

aluminum, calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, Nickel, lead, silicon and zinc.

The test conditions are determined by the results of the preliminary modeling of the balance of mass/energy. An important difference between computer simulation and real was the fact that computer simulation is performed on the example of the pure concentrate (approximately 50% zinc), and laboratory simulation using less clear rough concentrate (approximately 5% zinc).

Metallurgical analysis at this initial stage is carried out only for the samples obtained at the stage auxiliaries leaching at atmospheric pressure and after they are processed in the mould. Non-oxidizing plant for leaching is shown in Fig.

Vaporous phase is absorbed in a scrubber containing ferrous sulfate (3), with the aim of turning in which its hydrogen sulfide H 2S, obtained by leaching into elemental sulfur. The vacuum scrubber is more appropriate compared to high pressure in the reactor leaching, i.e. due to the possibility of leakage of hydrogen sulfide in the environment. Air is bubbled through the reactor leaching with the objective of ensuring the removal of hydrogen sulfide from the system, i.e. to shift reactions 6 to the right.

The main advantage of using crystallization (ZnSO4·H2O) in the system is not necessary to neutralize after leaching, thus, the leaching can be carried out at any desired concentration of Hcl, i.e. to ensure rapid kinetics.

Water balance process support in the process of evaporation to control the concentration of salt solution, compensation adding water in different threads, such as the flow of leach solution, water for washing, etc.

Leaching of sulphide ores

The method described below on the example of processing of zinc sulfide.

Use the concentrate obtained by flotation of sphalerite ore (field Gamsberg, South Africa). The concentrate is leached in 4 N. hydrochloric acid in the presence of a source of zinc chloride in solution at 85°C. the Leaching was completed in 15-30 minutes Initial concentration of zinc chloride (the rate of concentrate/Sol) is chosen so that to get rich leach solution at 80% saturation of zinc chloride. The leach solution is mixed with 98% sulfuric acid in a beaker with stirring, when this occurs the precipitation of zinc sulfate in an amount equivalent to the amount of leached zinc. The precipitate is crystalline zinc sulfate in the form of a hemihydrate, which corresponds to the calculated amount of salt. Salt optional calcined to obtain the oxide under suitable temperature, for example, 750°C in air, thus receive a gaseous phase containing at least 20% of sulfur dioxide, suitable for use in a device for producing sulfuric acid.

Crystallization

The main solution containing zinc, iron, sodium, in the form of chlorides and sulfates, get at 60°C, then the solution is added a stoichiometric amount of sulfuric acid. These tests carried out with a dual purpose: first, to determine the solubility of the basic components in the solution, and secondly, to determine the quantity and purity of the crystals formed during the addition of sulfuric acid. The research results shown in the table.

The results of the study of the solubility and crystallization
Sample Leaching agentCrystalline substance
Zn, g/lFe, g/lNa, g/lCL, g/lSO4, g/lZnFeNaCLSO4
20050324D42880031816740%0%0%5%41%
20050324D52900524073641%0%1%5%45%
20050324D698the 3.86161230- ----
20050324D73206,3233739438%2,5%0,3%4%46%

When the test sample 20050324D6 crystal formation was not observed due to the low initial concentration of zinc. The results obtained indicate that in systems containing Zn, can be used successfully precipitation crystallization for the regeneration of the primary reactants.

Getting chloride salt solution with a high concentration of acid (sverhchistoty solution)

Chloride salt solution is mixed with sulfuric acid or sulfur dioxide to obtain a salt solution containing hydrochloric acid in sverhsekretnoj concentration (i.e. the concentration at which the concentration of hydrochloric acid exceeds the azeotropic concentration). This process does not require complex equipment for distillation or expensive reagents. Thus, a simple and cheap method of obtaining solutions with extremely high the acidity for later use in certain processes, such as specific ways of dissolution, which is used in the purification of platinum group metals.

The resulting concentration of the acid, which can be below and above the azeotropic concentration is determined by the nature of the chosen chloride.

Getting chloride salt solution with high acidity

Magnesium chloride is dissolved at 100°C to a concentration of approximately 42,3 g/100 g saturated solution. Adding H2SO4in extreme cases, a complete precipitation of magnesium in the form of the monohydrate is formed approximately 50,3 g of salt in 49,7 g of water and 32.4 g of Hcl having a pH of 39%.

Getting chloride salt solution with high acidity

Magnesium chloride is dissolved at 80°C to a concentration of approximately 84,4 g/100 g saturated solution. Adding H2SO4in the case of deposition of 75% of the zinc in the form of the monohydrate is formed approximately 71,1 g salt to 28.3 g of water and 33.9 g of Hcl having a pH of 54%.

Although the present invention is described in detail on the example of special variants of its implementation, specialists in this field should understand that there are many possible modifications and other changes that do not fall within the essence and scope of the present invention. All these modifications, variations and changes included in the formula of the present invention.

1965)

1. Method of leaching the metal from its containing ore, comprising the following stages:
(a) leaching the ore in the presence of hydrochloric acid with the formation of soluble metal chloride in the leach solution,
b) adding sulfuric acid and / or sulfur dioxide in the leach solution with the formation of the precipitated solid metal sulfate or sulfite of metal in the leach solution,
C) regeneration of hydrochloric acid simultaneously with the deposition of solid metal sulfate or sulfite metal and regeneration of solid metal sulfate or sulfite of metal from the leach solution,
g) returning the regenerated hydrochloric acid with a high content of chloride ions and a low content of sulfate ions or sulfite on stage leaching, and
d) a continuous transformation of at least part of the hydrochloric acid from the solution into the vapor phase.

2. The method according to claim 1, in which the hydrochloric acid in the vapor phase returns to the step (a).

3. The method according to claim 1, in which hydrochloric acid is transformed into the vapor phase by heating.

4. The method according to claim 1, in which the hydrochloric acid in the vapor phase before returning to the step (a) is subjected to the driving of the e to remove the water.

5. The method according to claim 1, in which the metal sulfate or sulfite metal is characterized by the formula MeSOx·yH2O,
where Me denotes a metal,
x is 3 or 4, and
y is 0 or more.

6. The method according to claim 1, in which the source of the metal in the metal sulfate or sulfite metal is preferably iron ore.

7. The method according to claim 1, in which the ore is mainly an oxide or silicate ore containing non-ferrous metal.

8. The method according to claim 7, in which the ore is zinc oxide ore.

9. The method according to claim 1, in which the ore is of lateritic Nickel ore.

10. The method according to claim 9, in which the ore is Carolina or limonata ore.

11. The method according to claim 1, in which the ore is a sulfide, titanium, or aluminum ore.

12. The method according to claim 1, in which the metal leaching from ore selected from the group comprising Zn, si, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, CA, platinum group metals and gold.

13. The method according to claim 1, in which the metal composition of the metal sulfate or sulfite metal is a metal that leached, and additionally carry out the stage of decomposition of the metal sulfate or sulfite metal for regeneration of metal.

14. The method according to claim 1, wherein the metal in the metal sulfate or metal sulfite is less valuable metal, in comparison with metal, which is leached from the ore.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: procedure consists in leaching crumbled minerals with water solution of hydrochloric acid, in separation of solid phase and liquid phase products and in successive extraction of target components. As source minerals there are used poly-metallic slag of lead production additionally containing compounds of germanium. Leaching is performed with solution of hydrochloric acid of concentration from 6 to 30 wt % at ratio of solid and liquid phases 1:(1-5). Before separation of solid phase and liquid phase products ratio of solid and liquid phases is brought to 1: (8-20) by addition of water with transition of iron, zinc, and calcium into liquid phase product, while silicon and germanium - into solid phase product.

EFFECT: simplified extraction of target components.

3 cl, 2 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in following stages: ore leaching at presence of hydrochloric acid with production of soluble metal chloride in solution for leaching, addition of sulphuric acid into solution for leaching, extraction of metal sulphate from solution for leaching and regeneration of hydrochloric acid. As ore there is used oxide ore of non-ferrous metal, such as oxide zinc ore, laterite nickel ore such as saprolite or limonite, sulphide ore or titanium ore. Valuable metal is chosen from group including Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, metals of platinum group and gold. Valuable metal or less valuable metal, such as magnesium, can be metal in composition of metal sulphite. Regenerated hydrochloric acid is directed into re-circulation system into process of leaching.

EFFECT: raised efficiency of procedure.

40 cl, 36 dwg, 5 tbl

FIELD: metallurgy.

SUBSTANCE: procedure consists in processing refractory ore and concentrates with chlorine at presence of water and complex former in kind of sodium chloride, in converting gold into solution, in separating solution from precipitated sediment, and in washing sediment with water producing flush water. There are processed refractory ore and concentrates with low contents of gold and uranium, where uranium is additionally extracted. Also, for processing there is used chlorine in atomic or molecular state. Chloride or sodium sulphate are used as complex formers. Processing is carried out at weight ratio L:S (liquid: solid) (1-1.5) during 1-2 hours at temperature 20-70°C with simultaneous gold and uranium passing into solution.

EFFECT: simplified process, reduced power expenditures at maintaining high degree of gold and uranium extraction from poor bases and concentrates.

7 cl, 6 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: invention can be used to produce magnesium chloride, silica and red pigment. Serpentinite calcined at 680-750°C is treated with 4-8% hydrochloric acid solution with weight ratio of serpentinite to hydrochloric acid equal to 1:(15-40). The hot pulp is then decanted and filtered. The residue is dried to obtain silica, the filtrate is evaporated and silicic acid is separated. After separating silicic acid in form of sol-gel, hydrochloric acid is added to a solution containing magnesium and iron (III) chlorides until 4-8% hydrochloric acid solution is obtained. The obtained hydrochloric acid solution is used to treat a new portion of serpentinite. Further, the decantation, filtration, evaporation of filtrate, separation of silicic acid and treatment of the obtained solution with hydrochloric acid are repeated 3-5 times using new portions of calcined serpentinite. The solution concentrated that way at 90°C is mixed with serpentinite and filtered. Magnesium chloride is separated from the residue which contains iron (III) hydroxide. Said residue is treated at 350-400°C to obtain red pigment.

EFFECT: invention simplifies the processing serpentinite, improves environmental safety and reduces expenses and wastes.

1 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to procedures for extracting valuable metals from wastes including wastes of refining production. The procedure for processing silver containing lead wastes for extracting silver and lead in form of products consists in leaching wastes with solution containing hydrochloric acid to transit lead into solution and silver to sedimentation. Also leaching is carried out in three stages. At the first stage leaching is peformed with solution of lead chloride (PbCl2) at temperature 0°-25°C in concentrated hydrochloric acid (HCl) by placing wastes in this solution heated to temperature 40°-80°C. Major part of lead transits into solution. During the second and the third stages non-dissolved wastes are leached in 30-42% HCl and successively filtered till pure powder-like silver is produced in a non-soluble residue. Upon the first stage solution is cooled to 0°-25°C, crystals of PbCl2 are extracted out of it and combined with solutions of HCl after leaching at the first and the third stages; a new portion of wastes is directed to leaching. Implementation of this procedure at a lead plant of average output can collect yearly income of approximately 100 million dollars from sale of lead chloride.

EFFECT: raised efficiency of wastes processing, additional economic profit from implementation of this procedure at various metallurgical productions.

4 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to procedure for leaching precious metal from ore containing said precious metal. The procedure consists of three stages: leaching ore at presence of hydrochloric acid with production of soluble chloride of metal in a solution for leaching, in adding sulphur dioxide into the solution for leaching, in extracting metal sulphate or metal sulphite from the solution for leaching and in regenerating hydrochloric acid. As ore there can be used oxide ore of non-ferrous metal, such as oxide zinc ore, laterite nickel ore, such as saprolite or limonite, sulphide ore or titanium ore. Precious metal is chosen from a group including Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, metals of platinum group and gold. Precious metal or less precious metal, such as magnesium, can be a metal in composition of metal sulphate or metal sulphite. Regenerated hydrochloric acid is directed into a re-circulation system in the process of leaching.

EFFECT: increased efficiency of process.

45 cl, 36 dwg, 5 tbl

FIELD: metallurgy.

SUBSTANCE: procedure for processing titanium-magnetite concentrate consists in leaching concentrate with sulphuric acid and heating in presence of metal iron, in transfer of iron and vanadium into leaching solution and in concentrating titanium in residue. Further, solution is evaporated; iron containing residue is extracted and subjected to pyrolysis producing iron oxide and regenerated hydrochloric acid. Titanium containing residue is dried and baked producing a titanium product. Also titanium-magnetite concentrate is leached at concentration of hydrochloric acid of 15-19% and temperature 95-105°C. Iron-vanadium product in form of sediment of iron and vanadium hydroxides is settled from leaching solution by means of processing with ammonia solution at pH 2.4-2.8; there is produced iron chloride solution (II). Produced iron chloride solution is evaporated; iron containing sediment is extracted and the left sediment is subjected to pyrolysis. Titanium containing sediment is baked at temperature 700-800°C.

EFFECT: production of pure iron oxide (Fe2O3 not more than 99,3 wy %).

3 cl, 1 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: method involves treatment of the material by washing with water, burning the insoluble residue and leaching the ash. Before leaching, the ash undergoes secondary treatment by washing with water in solid to liquid ratio equal to 1:0.7-2.5.

EFFECT: reduced volume of pulp obtained during leaching, increased extraction of noble metals and recycling of potassium chloride.

2 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to extraction methods of precious metals and can be used for extraction of precious metals from mineral raw material containing chlorides of alkali and alkali-earth metals, e.g. sludges of potassium production. Extraction method of precious metals from clay-salt waste - sludges of potassium productions - containing chlorides of alkali and alkali-earth metals involves bulk concentrate obtained from them, roasting, leaching of precious metals from stub end and sorption of precious metals. Bulk concentrate is obtained till content of chlorides is 15 to 30%. Before roasting, the concentrate is granulated and subject to roasting at temperature of 500-950°C. Precious metals are leached from stub end by means of salt acid solution.

EFFECT: increasing complex extraction of precious metals.

5 tbl, 4 ex

FIELD: metallurgy.

SUBSTANCE: development method of ruthenium concentrate includes thermal treatment of it in mixture to sodium peroxide in iron pans at mass ratio of sodium peroxide to concentrate (0.8-2.0) and gradual temperature increase up to 500-600°C. Then it is implemented treatment of thermal treatment product in water and dissolving in hydrochloric acid with transferring and concentration of rutenum in chloride solution. After product thermal treatment in water received pulp is treated by deoxidising agent, in the capacity of which it is used Na2SO3 or C2H5OH, up to value achievement of oxidation-reduction potential equal to minus (100-200) mV (relative to chlorine-silver reference electrode). Received sediment is separated up to formed aquatic alkaline solution and subject to dissolving in hydrochloric acid.

EFFECT: achievement of deep development of concentrate with its following concentration in chloride solution with low saline saturation.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in following stages: ore leaching at presence of hydrochloric acid with production of soluble metal chloride in solution for leaching, addition of sulphuric acid into solution for leaching, extraction of metal sulphate from solution for leaching and regeneration of hydrochloric acid. As ore there is used oxide ore of non-ferrous metal, such as oxide zinc ore, laterite nickel ore such as saprolite or limonite, sulphide ore or titanium ore. Valuable metal is chosen from group including Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, metals of platinum group and gold. Valuable metal or less valuable metal, such as magnesium, can be metal in composition of metal sulphite. Regenerated hydrochloric acid is directed into re-circulation system into process of leaching.

EFFECT: raised efficiency of procedure.

40 cl, 36 dwg, 5 tbl

FIELD: metallurgy.

SUBSTANCE: procedure for processing final tailings of galvanic production consists in crumbling, leaching, separation of solution from sedimentation and in extracting heavy non-ferrous metals from produced solution. Also, final tailings are crumbled with mechanic-chemical activation by wet crumbling in form of pulp suspension at pH≤3 and ratio s (solid): l (liquid) = 1:(0.4-1) and temperature 60-90°C.

EFFECT: reduced harmful environmental impact and power expenditures due to elimination of thermal treatment stage at processing final tailings; raised efficiency of extraction of heavy metal compounds.

3 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: there are used soluble and insoluble anodes connected to separate sources of current for control over soluble anode dissolution during process of electrolysis and concentration of ions of metal in solution by means of correcting ratio of anode strengths of current of soluble and insoluble anodes at constant value of cathode density of current. Also, constant value of cathode density of current is achieved by constant area of cathode and sum of current strength on the soluble and insoluble anodes.

EFFECT: avoiding labour-intense operation of correction of electrolyte due to equalising cathode and anode current outputs at production of powders of metal.

8 dwg, 3 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in leaching at atmospheric or raised pressure, in production of effluent and in utilisation of ion-exchanging resins for absorption and extraction of nickel and cobalt. Before extraction of nickel and cobalt effluent in form of solution or pulp is treated with cation or chelate resin possessing selectivity relative to extraction of iron, aluminium and copper for their removal; it also increases pH of solution.

EFFECT: elimination of neutralisation stage of solution, efficient purification of effluent, prevention of nickel losses and avoiding division of solid and fluid phase of formed pulp at laterite ore leaching.

6 cl, 2 dwg

FIELD: metallurgy.

SUBSTANCE: procedure consists in leaching with chloride solution at supply of chlorine, in purification of solution from copper and in production of copper sulphide cake, in extracting concentrate of precious metals and in electro-extraction of nickel from solution. Prior to leaching matte is separated to a sulphide and metallised fractions. The sulphide fraction is subjected to leaching with chloride solution with supply of chlorine. The metallised fraction produced at separation of matte is added into pulp produced at leaching thus performing purification of solution from copper and its withdrawal to copper sulphide cake. Upon purification of solution from copper solution is purified from iron, zinc and cobalt. Copper sulphide cake is roasted and produced cinder is leached. Solution is directed to electro-extraction of copper, while concentrate of precious metals and chamber product are extracted from residue by flotation.

EFFECT: reduced material and operational expenditures and losses of non-ferrous and precious metals.

2 cl, 12 ex, 2 dwg

FIELD: metallurgy.

SUBSTANCE: procedure consists in processing wastes with sulphuric acid at raised temperature, in supplying hydrogen peroxide, in introducing rhenium, nickel and cobalt into leaching solution and in concentrating tungsten, niobium and tantalum in insoluble residue. Further, solution is separated from insoluble residue; extraction of rhenium from solution is leached with secondary aliphatic alcohol. Extract is washed and rhenium is re-extracted with leaching solution upon extraction. Hydrogen peroxide is supplied after main part of nickel and cobalt have passed into solution at maintaining redox potential in interval of 0.50-0.75 V relative to a saturated chlorine-silver electrode, while extraction of rhenium, extract washing and rhenium re-extraction are carried out on 2-5 steps.

EFFECT: increased extraction of rhenium at reduced consumption of oxidant, increased safety of procedure due to separated in time operations followed with release of hydrogen and oxygen.

6 cl, 4 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in underground leaching nickel with solution of sulphuric acid and in pumping product solution out. Further, acidity of product solution is reduced, and nickel is sorbed on ionite resin with its following desorption. Upon desorption raffinate of nickel sorption is made-up with sulphuric acid and directed to leaching as leaching solution. Also, excessive sulphuric acid is sorbed on separate ionite with following desorption for reduction of product solution acidity. Upon nickel sorption raffinate is made-up with sulphuric acid and with sulphuric acid after operation of its desorption.

EFFECT: simplification of process, increased ecological safety and reduced consumption of sulphuric acid.

1 dwg, 1 tbl

FIELD: metallurgy.

SUBSTANCE: processing procedure consists in supply of charge into slag melt in oxidising (melting) zone of two-zone furnace. Also charge contains source raw material and fluxes, liquid or solid processed slag, carbon containing material and oxygen containing blast supplied in quantities required for complete combustion of carbon and hydrogen with maximal heat release. Before supply of mixture of source raw material and fluxes into the oxidising (melting) zone of the furnace their mixture is preliminary roasted and supplied at temperature 500-1300°C. Melted charge forms slag melt coming into a furnace zone of reduction, whereto oxygen containing blast and carbon containing material are supplied. Notably, they are supplied at amount required for reduction of extracted material into a metal phase and for compensation of heat consumption by means of after-burning gases of the reduction zone above melt, whereupon melt products are tapped.

EFFECT: raised efficiency of melting process and reduced consumption of oxygen and carbon containing material.

3 cl, 4 tbl, 5 dwg, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises dissolving wastes in acid electrolyte by applying AC electric field thereto. Dissolving is performed in nitrate or sulphate electrolyte on applying half-wave asymmetric AC industrial-frequency current and on using second electrode made from tantalum or niobium plates. Note here that anodic dissolution is carried at acidity of nitrate electrolyte at the level of 200-250 g/l HNO3, while that of sulphate electrolyte making 150-200 g/l H2SO4 at 20-40°C and current of at least 1 kA.

EFFECT: increased process rate, better ecology.

3 cl, 3 tbl, 3 ex

FIELD: metallurgy.

SUBSTANCE: method involves drying of concentrate and melting in the oven. At that, melting is performed in cylindrical reaction chamber of the oven at bubbling and rotation of the molten metal with oxygen-containing jets in sulphur to oxygen ratio 1:(1-1.1). After melting is completed, the molten metal is separated into slag and matte in collector.

EFFECT: continuous high efficiency method of processing of copper-nickel sulphide concentrates so that high-grade mattes are obtained and content of cobalt in slag is decreased.

5 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in leaching crumbled minerals with water solution of hydrochloric acid, in separation of solid phase and liquid phase products and in successive extraction of target components. As source minerals there are used poly-metallic slag of lead production additionally containing compounds of germanium. Leaching is performed with solution of hydrochloric acid of concentration from 6 to 30 wt % at ratio of solid and liquid phases 1:(1-5). Before separation of solid phase and liquid phase products ratio of solid and liquid phases is brought to 1: (8-20) by addition of water with transition of iron, zinc, and calcium into liquid phase product, while silicon and germanium - into solid phase product.

EFFECT: simplified extraction of target components.

3 cl, 2 ex

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