Procedure for production of high porous silver sponge out of silver containing materials (versions)
SUBSTANCE: here are disclosed 2 versions of fabrication of high porous silver sponge where as source of silver there are used silver salts or silver alloys successively converted into salts. The versions of the procedure consist in preparing concentrated chloride solution whereat silver salt is dissolved in accordance with its solubility at temperature of solution boiling. Salt of polyvalent metal of lead chloride at amount equal to amount of dissolved silver is introduced into prepared solution. Further, silver-lead sponge is settled with zinc. Contaminating substances and lead are removed from settled sponge which is successively washed and dried.
EFFECT: accelerated production of silver sponge due to reduced time for its sedimentation; qualitative stable high porosity of produced silver sponge.
2 cl, 1 dwg, 1 tbl, 3 ex
The invention relates to the field of metallurgy of non-ferrous and noble metals, in particular to methods for selection of precious metals from waste, including refining production.
A method of obtaining silver powder [RF patent 1605419]. The method includes restoring containing silver sulphate with hydrogen as the source connection take the crushed alloy sulfate silver sulfate of an alkali metal selected from the group of: sodium, potassium, lithium, and after restoration of the remains of the alkali metal sulfate is removed by washing with water followed by filtration and drying.
The method has significant drawbacks: the size of the silver powder depends on the degree of grinding of raw materials, and the resulting silver, despite washing it with water, will still contain fused in him sulfate of an alkali metal.
A prototype of the selected method of obtaining silver powder [application OF No. 2000111932/02]. The method involves the dissolution of silver at the anode, the deposition of metallic sponge at the cathode, drying and sifting of the powder. In the electrolyte is injected chemical compounds that are able to oxidize metal ions and regenerated at the cathode, complexing agents and colloidal solutions of metals as centers of crystallization of the metal. The powders are further treated, as well as producing is their warm-up in water-diluted solution of a metal salt to extend the range of dispersion of the powder. After washing powder moistened with a saturated solution of ammonium carbonate, wring out and moistened with ethyl alcohol.
The disadvantages of the method is the deposition rate of silver sponge at the cathode is very limited, which is why you can get high-quality sponge in this way is impossible, as is generally formed powder. Due to the developed surface of the sponge in the deposition process is constantly changing the current density and, consequently, the sponge at the beginning of the deposition will have different properties (density, specific surface area) from the sponge at the end of the deposition. The method does not offer effective removal introduced into the electrolyte polyvalent ions.
The goal is to accelerate the process of obtaining silver sponge, improving the quality of the besieged sponge by improving its purity and obtaining a stable high-porous surface.
Proposed option 2 method of obtaining highly porous silver sponge of silver-containing materials.
The first variant of the method involves the preparation of a solution of silver sponge, the deposition of silver from a solution by the introduction of zinc. As a silver-containing materials choose silver salt. Pre-prepare a concentrated chloride solution of calcium chloride or zinc which is dissolved silver salt in accordance with its solubility at a temperature of capturesaver, with the subsequent introduction in the prepared solution of the silver salt of chloride of lead in number equal to the number of dissolved silver. Silver precipitated in the form of a metallic lead-silver sponge, and after leaching from lead-silver sponge to remove contaminants and lead by dissolving in hydrochloric acid to obtain a highly porous silver sponge.
The second way of obtaining highly porous silver sponge is also preparing a solution of a silver salt and precipitate the silver from the solution by the introduction of zinc. As a silver-containing material is chosen alloys of silver, which is dissolved in nitric acid, add water soluble chloride until complete precipitation of silver chloride, to prepare a solution of a silver salt. Before preparing a solution of a silver salt to prepare a concentrated solution of calcium chloride or zinc, in which dissolve silver chloride in accordance with its solubility at the boiling temperature of the solution. In the prepared solution of silver salt is administered chloride of lead in number equal to the number of dissolved silver. Silver precipitated in the form of a metallic lead-silver sponge, and after leaching from lead-silver sponge to remove contaminants and lead by dissolving in hydrochloric acid to obtain a highly porous the silver sponge.
As salts of polyvalent metals may be used and any lead salts, when administered in concentrated chloride solution any lead salt will react with the formation of chloride of lead.
In the proposed method, a significant difference is that pre-create special conditions for contact electrolysis (cementation) - deposition sponge zinc. As inert material, soosazhdenie with silver and subsequently removed, is structured lead sponge. Silver, soosazhdenie together with lead, also has the structure of a sponge. To obtain lead of sponges with a highly developed surface of their deposition must be made from concentrated chloride solutions. As such solutions it is possible to use solutions of calcium chloride and a solution of chloride of zinc.
Solutions of zinc chloride allow you to get more silver sponge, as in concentrated (close to saturated) solution of zinc chloride solubility of silver chloride is much higher than in concentrated solutions of calcium chloride.
Options allow you to speed up the process of obtaining silver sponge by reducing the deposition time of the sponge with the stable-highly porous surface, since the degree CE the orientation (deposition) of lead and silver zinc is about 95% within the first 30 seconds there is virtually instantaneous and improve its quality due to the purity of the source materials. Thus, the distinctive features are essential and necessary to solve the task.
For the preparation of the chloride solution of chloride of silver, where silver is in the form of stable soluble chloride complexes may be used in any silver salt. Dissolution in concentrated chloride solution will occur due to the exchange reaction:
However, it is preferable to introduce the silver svezheosazhdennoi of silver chloride (AgCl).
As sources of silver to obtain a silver sponge can be used silver alloys and pure silver. In this case, a metal alloy or silver dissolved in nitric acid, the resulting solution was gradually added a solution of any chloride (NaCl, KCl, CaCl2and others) to complete precipitation of silver chloride. Svezheosazhdennoi silver chloride is separated from the solution and then dissolved in concentrated chloride solution (e.g. a solution of calcium chloride (CaCl2) or zinc chloride (ZnCl2due to the complex formation:
The use of the Finance solutions CaCl 2and furthermore solutions ZnCl2for the dissolution of AgCl is much preferred solutions of NaCl and KCl, as it allows to reach in a solution of greater concentration of the chloride ions and hence to achieve much higher solubility of silver chloride.
To implement the proposed method to obtain silver sponge, you need to take pre-heated to a temperature of 60°With a solution of calcium chloride or zinc chloride with pH 1-0, must be dissolved in this solution of a silver salt such as silver chloride. The solubility of salt is calculated [Mathis L. Introduction to chemical equilibrium and kinetics. M.: Mir, 1984. - 484 C.]. Then add to a solution of a lead salt such as the chloride of lead (PbCl2) so that the amount of lead in the solution was equal to the amount of dissolved silver (in moles) and spend the deposition Svencioneliai sponge. What in the solution at a temperature of 60°C to introduce 2-3 reception repolimerizovanny in hot 1% HCl zinc powder (W/T=5-20), taken with a 20% excess for the deposition of silver and lead. The resulting lead-silver sponge must be separated from the solution, rinse with hot acidified water and dissolve the lead sponge in concentrated HCl when heated. As a result of dissolution of lead will remain pure silver sponge. The rate of feed of activated zinc dependence of Olena more complete and effective deposition of silver on the new, newly formed surface of the lead sponge. Despite the fact that normal, fused lead is dissolved in HCl slowly enough, the dissolution of lead sponge takes a few minutes for the optimization of this process it is necessary to use concentrated HCl as the acid, the higher the solubility of the resulting PbCl2.
By well-known methods [Piosenki. The technique of laboratory work. M.: Chemistry, 1973. - 717 S.] preparing calcium chloride solution with a content of CaCl23.4 M and pH 1.0. 1 DM3calcium chloride solution when heated to 108°C (the boiling point of the solution) was dissolved 1.2 g of AgCl and 2.8 g PbCl2. The solution is cooled to a temperature of 60°C, and thereafter the deposition of lead-silver sponge, for which it is entered 3 times, 1.5 g of zinc dust, pre-reportprovides in 30 ml of 1% HCl at a temperature of 80°C. the Resulting lead-silver sponge filtered, washed with 1% hot HCl and heated in 100 ml of 39% HCl to dissolve lead. The resulting silver sponge is separated from the solution, washed first net 39% HCl and then with distilled water and dried. Micrograph of a sample of silver sponge obtained from calcium chloride solution presented on figa.
According to known methods is the IR [Piosenki. The technique of laboratory work. M.: Chemistry, 1973. - 717 S.] preparing chloride-zinc solution with a content of ZnCl210 M and pH 1.0, analogously to example 1. 1 DM3chloride of zinc solution when heated to 136°C dissolved 12 g of AgCl and 28 g PbCl2. The solution is cooled to a temperature of 60°C, and thereafter the deposition of lead-silver sponge, for which it is entered 3 times, 15 g of zinc dust, pre-reportprovides in 100 ml of 1% HCl at a temperature of 80°C. the Resulting lead-silver sponge filtered, washed with 1% hot HCl and heated in 1000 ml of 39% HCl to dissolve lead. The resulting silver sponge is separated from the solution, washed first net 39% HCl and then with distilled water and dried. Micrograph of a sample of silver sponge, obtained from the chloride of zinc solution, presented in figure 1 Century
1.0 g of a silver alloy containing silver is 87.5% is dissolved in 10 ml of a solution of HNO3(63%), heated to 50-60°C, the resulting solution is added 200 ml of water, 5 ml of 10% NaCl solution, 5 ml of 1% solution of polyacrylamide, the solution was heated and boiled for 5 minutes, then cooled to 20°C. and filtered the resulting silver chloride. The resulting silver chloride is dissolved in 1 DM3calcium chloride solution with a content of CaCl23.4 M and a pH of 1.0 (when otbelennogo analogously to example 1) when heated to 108°C. then in the same solution dissolves when heated and 2.26 g of the chloride of lead (PbCl2). The solution is cooled to a temperature of 60°C, and thereafter the deposition of lead-silver sponge, for which it is entered in 2 doses of 1.0 g of zinc dust, pre-reportprovides in 30 ml of 1% HCl at a temperature of 80°C.
The resulting lead-silver sponge filtered, washed with 1% hot HCl and heated in 100 ml of 39% HCl to dissolve lead. Received silver sponge is separated from the solution, washed first net 39% HCl and then with distilled water. Such washing is necessary to first dissolved in HCl soluble in water chlorides: AgCl, CuCl, PbCl2and others, and the final rinsing in clear water allows you to remove water soluble impurities and residues from the HCl. Comparative results of the examples presented in the table.
|The yield and properties of silver sponge depending on the method of their derivation|
|The way to obtain||The mass of sponge||Bulk density sponge, g/cm3|
|From AgCl and solution of CaCl2(example 1)||0,789 g||1,46|
|From AgCl and solution of ZnCl2(example 2)||8,516 g||1,21|
|Alloy and solution of CaCl2(example 3)||0,824 g||1,45|
As the table shows, the use of chloride-zinc solutions can be obtained from 1 DM3almost 10 times more silver sponge than in the case of application of calcium chloride solutions. Marginal density of the samples due to their high porosity (so, the usual silver has (at 20°C) density of 10.50 g/cm3), which fully meets the task - getting the silver sponge with the stable-highly porous surface. Micrograph obtained sponges are presented in figure 1. From the table and figure 1 shows that as in the case of chloride-zinc solutions, and in the case of calcium chloride solutions, the size of the microparticles sponge consistently the same for this type of solution. In addition, the direct receipt of lead-silver jaws contact electrolysis (by precipitation with zinc) is about 5 minutes, that allows significantly intensify this process compared with the electrolytic method used in the prototype, as usual e is Stralis can last hours or even days.
The acceleration of the process of obtaining silver sponge by reducing the deposition time of the sponge with the stable-highly porous surface is achieved by cementation (deposition) of lead and silver in zinc, which occurs at the level of 95% within the first 30 seconds, which is almost instantly.
1. The method of obtaining highly porous silver sponge from silver-containing material, comprising preparing a solution of a silver salt, the deposition of silver from a solution by the introduction of zinc and flushing of sediment, characterized in that as a silver-containing materials choose silver salt before preparing a solution of a silver salt to prepare a concentrated solution of calcium chloride or zinc which is dissolved silver salt in accordance with its solubility at the boiling temperature of the solution, followed by the introduction in the prepared solution of the silver salt of chloride of lead in number equal to the number of dissolved silver, silver precipitated in the form of a metallic lead-silver sponge and after leaching from lead-silver sponge remove contaminants and lead by dissolving in hydrochloric acid to obtain a highly porous silver sponge.
2. The method of obtaining highly porous silver sponge from silver-containing material, comprising preparing a solution of silver is th salt, the deposition of silver from a solution by the introduction of zinc and flushing of sediment, characterized in that as a silver-containing material is chosen alloys of silver, which is dissolved in nitric acid, add water soluble chloride until complete precipitation of silver chloride, to prepare a solution of a silver salt before preparing a solution of a silver salt to prepare a concentrated solution of calcium chloride or zinc, in which dissolve silver chloride in accordance with its solubility at the boiling temperature of the solution, followed by the introduction in the prepared solution of the silver salt of chloride of lead in number equal to the number of dissolved silver, silver precipitated in the form of a metallic lead-silver sponge and after leaching from lead-silver sponge to remove contaminants and lead by dissolving in hydrochloric acid to obtain a highly porous silver sponge.
SUBSTANCE: procedure consists in settling silver with addition of zinc powder. Before sedimentation of silver zinc powder is preliminary activated in 1-5 % solution of HCl at temperature 80-100°C. Lead chloride at amount of 2-15 g/dm3 is added into chloride solution before sedimentation. The procedure of sedimentation consists in adding activated zinc powder to chloride solution heated to 50-60°C and in successive conditioning for forming a lead sponge and sedimentation of silver on it. After conditioning the formed sponge is broken and solution is mixed. Activated powder of zinc is added in big portions.
EFFECT: raised efficiency of chloride solution purification, increased output of silver, reduced consumption of zinc and time of sedimentation, and thereby reduced cost of process.
2 cl, 1 tbl, 3 ex
SUBSTANCE: inventions relate to gold extraction from solutions with low concentration at presence of ions of other metals, for instance cleaning solutions of gold-extracting plants, brines of potassium manufacturing, geothermal water, water of brine lakes and salt water. Essence consists in that through powder of metal-restorative it is passed gold-containing solution with low concentration at presence of ions of other metals during 2-240 hours. In the capacity of metal-restorative it is used lead-plated zinc powder of grade +0.001 mm - 2 mm with lead content 1-90 wt %. or powders of metals, used at temperature of solution not less than 50°C and selected from the group: Zn, Fe, Ni, Pb, Sn, Sb, of grade +0.1 mm - 5 mm. Additionally before cementation powders are placed in cartridge. Received after cementation gold-containing concentrate is separated by means of intensive mechanical agitation, it is treated by nitric or acetic acid. Gold sediment is separated by filtration, dried and molten with fluxing additives with receiving of crude metal.
EFFECT: increase of effectiveness and selectivity of gold extraction from solutions with low concentration.
3 cl, 1 dwg, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to process engineering and can be used for processing antimony-based alloys containing noble metals in concentrations over 0.1%. Proposed method comprises dissolving alloys in solution containing acid and extracting noble metals from said solution by cementing. Prior to dissolving alloys, lead is remove therefrom by processing with solvent. Alloys are dissolved by solution containing hydrochloric acid and hydrogen dioxide or sodium persulphate. Noble metals are cemented by antimony-based alloys with minor concentration of noble metals or cathode antimony powder with grain size varying from 100 to 74 mcm, or by gold-antimony flotation concentrate with grain size varying from 100 to 74 mcm to produce an alloy enriched with noble metals cements noble metals. Now, noble metals are extracted from obtained products.
EFFECT: treatment of alloys with wide range of noble metal concentrations within 0,1 to 1,3 %.
4 cl, 2 tbl, 5 ex
FIELD: process engineering.
SUBSTANCE: invention relates to process engineering and can be used in gold cementation with rotary solution flow. Proposed device comprises metal cementing gadget, initial solution inlet branch pipe, solution outlet branch pipe, cementation product discharge branch pipe and vibrator with vibro drive. Device incorporates two tanks representing spiral of Archimedes and arranged one above the other around central common perforated pipe with rubber shock absorbers made on every tank. Aforesaid metal cementing gadget is arranged in baskets mounted inside said tanks. Solution discharge branch pipe is located at lower tank bottom. Basket accommodating said metal cementing gadget represents a vessel with walls perforated along solution flow, holes diameters varying from 2 mm to 3 mm. Vessels arrangement allows working solution to flow in opposite directions.
EFFECT: increased rate of cementation.
7 cl, 1 dwg
SUBSTANCE: invention relates to methods of vanadium sedimentation from water solutions and can be used in hydrometallurgy of rare refractory metals, particularly receiving of vanadium oxide (V+5) of high purity. Method of vanadium extraction from sodium-bearing solutions includes electrodialysis of solution for membrane withdrawal of sodium cation from solution and sedimentation of ammonium pol-vanadate. Electrodialysis is implemented at circulation of solution through working chamber of electrodialysis apparatus and at achievement of pH 6.5-7.5 circulating solution is treated by ammonia water or ammonia. Treatment is implemented up to molar ratio Na:V<0.1.
EFFECT: providing of intensification of sedimentation process of vanadium, improvement of finished product and elimination of discharge of industrial flows.
1 dwg, 4 ex
SUBSTANCE: device for extraction of noble metals from solutions by cement injection contains tank and container, filled with metal-cement injector. Tank is outfitted by jacket heating and is implemented with conical end, hatch of reactants loading, branches of discharge and filling in of solutions and sealed cover. Container with metal-cement injector is located on sealed cover of tank and allows horizontal branch of feeding of solution into container. It also allows vertical branch, bottom end of which is deepened into tank for abstraction of solution from tank by means of screw electric pump. Bottom of container allows punching with diametre of openings 2.5-3 mm. Tank is implemented from titanium.
EFFECT: efficiency and operating safety of the device.
3 cl, 1 dwg, 2 ex
SUBSTANCE: recovery technique of gallium from alkaline solutions by means of cementation by aluminum gallium with release of hydrogen includes periodical feed of gallium by feeding of granulated aluminium. Process is implemented at renovation of air-gas mixture above surface of solution by means of ventilation with constant air intake and measurement of hydrogen concentration in air-gas mixture above surface of solution. Feeding of aluminium in gallium is implemented at achieving of hydrogen concentration less than prescribed value.
EFFECT: improving of controllability and reliability growth of the control for cementation process.
2 dwg, 1 ex
SUBSTANCE: method includes treatment of source solution with liquid alloy of gallium and aluminium, at that treatment is performed by means of introducing gallium containing solution into liquid alloy of gallium and aluminium into bubbler under pressure. Solution is introduced at differential pressure in holes of the bubbler 0.01-1 MPa.
EFFECT: optimisation of volume exchange in process of gallium cementation; avoiding undesirable formation of aluminium hydroxide and simplification of design of cementation device.
1 dwg, 1 tbl, 1 ex
FIELD: non-ferrous metallurgy; cementation cleaning of sulfate zinc solutions from admixtures.
SUBSTANCE: proposed method includes stage of cleaning the solutions from copper and cadmium at obtaining copper-and-cadmium cake followed by leaching-out this cake to copper cake and final cleaning stage when remaining admixtures are removed and copper-containing solution and antimony-containing additive are delivered. Solution of reworking of copper cake is used as copper-containing solution. Reworking of copper cake includes washing-off admixtures continued for 4-6 h at temperature of 50-70°C and final pH of 2-3 and subsequent stage of sulfuric acid leaching of copper from washed-off cake.
EFFECT: low cost of cementation cleaning.
FIELD: nonferrous metallurgy; methods of purification of zinc sulfate solutions.
SUBSTANCE: the invention is pertaining to the field of nonferrous metallurgy, in particular, to the method of purification of zinc sulfate solutions from impurities and may be used at purification of the zinc sulfate solutions from impurities. Purification of the indicated solutions is exercised by the zinc powder cementation of cobalt and other impurities with the dosing additions of antimony and at the presence in the solution of copper. At that the solution is additionally introduced with lead sulfate in the amount in 4-8 times exceeding the concentration (in mg/l) of cobalt in the solution being subjected to the purification.
EFFECT: the invention ensures purification of zinc sulfate solutions.
SUBSTANCE: procedure consists in saturating pulp prepared from ore with oxygen and in introducing leaching reagents and sorbents. Further, there are performed sorption leaching with saturation of sorbent with metal impurities and partially with valuable metals, in counter-flow sorption of base part of valuable metals and in withdrawing sorbents saturated with valuable metals. Also, before introduction of leaching reagents activating solution, treated with light radiation in ultraviolet region of spectre or photo-electro-chemically treated, is introduced into pulp prepared out of ore containing valuable metals in dispersed form. Sorption leaching is carried out in electric field for electro-sorption extraction of primarily leached metals with periodic withdrawal of sorbent from zone of electro-sorbtion.
EFFECT: reduced losses of industrially valuable metals.
SUBSTANCE: invention relates to metallurgy of noble metals, in particular, to method of processing nitration hydroxides in refinery of platinum metals containing chalcogenides, tin, arsenium and platinum group metals, gold and silver. Proposed method comprises leaching of hydroxides and extracting basic metal compounds from the solution. Hydroxide leaching is carried out for 1-2 h by alkali solution with concentration of 140-180 g/l with l:S ratio varying from 3:1 to 4:1, temperature 80-90°C, and introducing hydrazine hydrate into pulp to reach OVP of minus 400-600 mV relative to reference silver-chloride electrode. Then, alkaline solution is separated from insoluble residue that concentrates platinum metals. Now, extraction of basic metals is carried out in processing alkaline solution by sulfuric acid to pH=4-5 to produce hydroxide precipitate of tin, arsenium, selenium and tellurium, and by filtration, or processing of alkaline solution by sulfuric acid to pH 0.5-1.0 along with adding iron powder to OVP varying from 0 to minus 100 mV, and filtration of obtained cementates obtained on the basis of selenium and tellurium, and processing the solution by alkali to pH = 4-5 with deposition of tin and arsenium hydroxides. Invention allows extracting up to 85% of Se and Te into target products, 90% of Sn and As into secondary hydroxides at minimum transition (less than 1%) into PMH.
EFFECT: over 99% of platinum metals left in refinery cycle, reduced processing cycle.
SUBSTANCE: method involves supply of ores or concentrates in the form of pulp with solution of sodium chloride to electrical action zone. At that, electrical action is performed in two steps: at the first step - with electrodialysis in electrolysis unit with the space divided with porous membrane till hydroxyl-radicals, metastable hydric dioxide, ions of hydroxonium, gas-water emulsion enriched with active oxygen and/or chloride is produced in anode chamber, and gas-water emulsion enriched with hydrogen and alkali components is produced in cathode chamber. At the second step - jump-like voltage increase on electrodes to the values generating electric charge destroying membrane for anolyte pulp fraction to be mixed with catholyte pulp fraction and forming plasma shaped medium and secondary active reagent complexes.
EFFECT: increasing efficiency and intensity of leashing process.
SUBSTANCE: procedure consists in storage of massif of rejects, in supply of leaching solution, in collection of production solution and in extraction of useful components out of it. Prior to supply of leaching solution massif of rejects is dried. Hygroscopic material is laid on surface of massif. Leaching solution is supplied into massif to complete saturation. Production solution accumulated in the hygroscopic layer is removed by pressing, evaporation, wave vibrations or by gravity flow. Also leaching solution is supplied in proportion to rate of removal of production solution from hygroscopic material.
EFFECT: reduced labour intensiveness and increased output of useful elements extraction.
5 cl, 1 dwg
SUBSTANCE: method involves processing by using ammonium chloride, obtaining of chlorides solution, extraction of zinc from the solution. At that, sulphide, oxidated or mixed zinc-lead containing ores are subject to processing by using solid ammonium chloride in quantity of 100-130% of stoichiometric ratio at temperature of 200-320°C. Solution of chlorides is obtained by water leaching of the obtained mixture of chlorides. Iron is separated in the form of hydroxide from the obtained solution at pH 4. After iron is separated, zinc is extracted in the form of zinc hydroxide by adding ammonium to the solution to pH 7. Obtained hydroxides are calcinated till oxides are obtained. Lead is extracted from residual water leaching in the form of chloride by leaching with sodium chloride solution with concentration of 300-320 g/l at temperature of 70-95°C.
EFFECT: possibility of developing effective and environmentally safe technology for processing of sulphide, oxidated or mixed zinc-lead containing ores.
SUBSTANCE: method involves treatment of wastes with a calcium polysulphide solution. Before treatment with the calcium polysulphide solution, the wastes are mixed with an oxidising agent which contains active chlorine in amount of 0.15-10.0 % of the weight of the wastes. Water is then added and the mixture is held. The obtained mixture is treated with a calcium polysulphide solution in ratio of calcium polysulphide solution to the mixture equal to 1-4:10 wt % respectively, and the reaction mixture is then held.
EFFECT: avoiding the need to use complex equipment, recycled wastes which are converted from hazard class 1 to hazard class 4 contain mercury sulphide inclusions which are not hazardous to the environment and are safe for disposal.
5 cl, 1 tbl, 9 ex
SUBSTANCE: invention relates to atomic industry and can be applied in technological processes of obtaining uranium tetrafluoride and in production of metallic uranium. Method of obtaining uranium tetrafluoride includes dissolution of uranium dioxide, sedimentation of uranium tetrafluoride from obtained solution by supplying hydrofluoric acid. After that carried out are pulp filtration, sediment washing, drying and burning. Dissolution of uranium dioxide is carried out in mixed solution of hydrochloric and hydrofluoric acids obtaining solution of complex uranium compound with uranium concentration up to 480 g/l. Uranium tetrafluoride from solution is precipitated in form of crystal hydrate by dosed supply of hydrofluoric acid during 15-30 min, without forced heating of reaction medium.
EFFECT: increase of process productivity and reduction of expenditures.
SUBSTANCE: invention refers to metallurgy, particularly to procedure for purification of manganese concentrates from phosphorus. The procedure consists in agglomeration of concentrate with sodium salts at 950-1000°C and weight ratio 1:0.4, and in successive water leaching with transfer of phosphorus into solution. Further concentrate is filtered and dried. Also leaching is carried out under effect of ultrasonic oscillations of 18·103-22·103 Hz per second frequency during 15-30 minutes. Finished concentrate is filtered and dried in ultrasonic fields of 18·103-22·103 Hz per second frequency.
EFFECT: upgraded quality of manganese concentrate by means of reducing concentration of phosphorus in it.
2 tbl, 1 ex
SUBSTANCE: method of titanium dioxide obtainment involves stages of (a) iron-containing titanium ore processing by aqueous solution of NH4F and/or NH4HF2; (b) filtration of obtained water suspension with further separation of solid sediment and aqueous solution containing titanium salts; (c) hydrolysis of the aqueous solution obtained; (d) filtration and pyrohydrolysis of solid sediment. Hydrolysis involves first stage at pH 7.0-8.5 and second stage at pH 10.0-13.0. Suspension obtained at the fist hydrolysis (c) stage is filtered to obtain aqueous solution containing titanium salt (NH4)2TiF6 with (NH4)3FeF6 concentration under 0.01 wt %, and sludge fraction containing ammonia oxyfluorotitanate and (NH4)3FeF6. Aqueous solution undergoes second hydrolysis (c) stage to obtain water suspension. Pyrohydrolysis involves first stage at maximum temperature of 450°C and second stage at maximum temperature of 1000°C.
EFFECT: waste-free obtainment of titanium dioxide resistant to UV radiation and not requiring additional grinding, reduction of power consumption.
22 cl, 1 dwg
SUBSTANCE: invention refers to noble metal metallurgy and can be applied in processing technology for platinum-group metal concentrate based on iron and nickel. Processing method for platinum-group metal concentrates on iron and nickel base for platinum-group metal recovery includes concentrate processing with hydrochloric acid with transition of platinum-group metals to solution. Further insoluble sediment is separated, solution is treated with sodium nitrite, and iron hydroxide sediment is removed. Before processing with hydrochloride acid, the concentrate is repulped in water, the pulp is heated, nitric acid is added in amount required for dissolution of about 60% of iron and nickel, and the pulp is heated for 4-5 hours at 85-100°C. Hydrochloric acid processing involves addition of hydrochloric acid in amount required for dissolution of remaining iron, nickel and platinum-group metals and heating for 4-5 hours more at 85-100°C. Phosphoric acid or sodium phosphate is added to the solution before sodium nitrite treatment.
EFFECT: deep recovery of concentrate, prevented formation of explosive air and hydrogen mix and extremely poisonous phosphine gas (PH3).
1 tbl, 1 ex
SUBSTANCE: procedure consists in concentration of ore with production of flotation gold containing concentrates, in bio-oxidation with production of ferric iron in liquid phase, in separation of solid phase from liquid phase and in production of bio-cakes, in their sorptive cyanidation, in gold desorption, in its electrolytic extraction and in successive melting into ingots of dore alloy. Prior to bio-oxidation there is performed oxidation of flotation gold containing concentrates with solution of ferric iron produced at production of bio-cakes with filtration; successively, solid phase is separated from liquid phase. Separated solid phase is subjected to bio-oxidation and it is performed at pH 1.5-1.8 and contents of solid phase 15-20 % and at such intensity of aeration-mixing, which is characterised with volume coefficient of weight transfer for oxygen 200-800 h-1 to oxidation of sulphide minerals and ions of ferrous iron in gold-containing concentrate.
EFFECT: intensified process of bio-oxidation of sulphide concentrates containing refractory gold and increased efficiency of extracting gold with cyanidation.
3 cl, 2 tbl, 2 ex