Plasma process and device for extraction of precious metals
FIELD: process engineering.
SUBSTANCE: invention relates to extraction of precious metals. Continuous extraction of precious metal composition from raw stock comprises heating of said stock in plasma kiln to produce slag top layer and fused metal bottom layer. Then, slag layer and fused metal layer are removed. Fused metal removed layer is solidified and fragmented for extraction of precious metals from produced fragments. Note here that said raw stock comprises material containing precious metal and collector metal. The latter is either metal or alloy able to form solid solution, alloy or intermetallide compound with one or several precious metals. Proposed device comprises plasma kiln, teeming table for continuous teeming of fused metal pool to form solidified sheet, fragmentation device and separation unit for extraction of precious metals from sheet fragment alloys.
EFFECT: higher yield.
20 cl, 11 dwg, 2 ex
The present invention relates generally to the field of metallurgical extraction, in particular, to a method, product and apparatus relating to the extraction of platinum group metals and other precious metals, hereinafter called the precious metals.
The level of technology
Metals can be extracted from a number of primary and secondary sources. Primary sources include ore and naturally occurring solutions and mixtures containing metal ions. Secondary sources include waste, spent catalysts, residues of processes and mine waste. Due to the shortage of certain metals and the expense and difficulties associated with the extraction of metals from primary sources, the key to the extraction of metals from secondary sources are the processes of retrieval.
Of particular interest are the precious metals, especially platinum group metals, which are expensive due to their low prevalence in nature and complexity of the processes that are required for their extraction and refining of primary sources. Although the platinum group metals found in natural ores, such as sperrylite (platinum arsenide), these metals can also be obtained by recycling waste containing metals of platinum group. Platinum group metals have excellent catalytic properties which, and appropriate waste are often catalytic waste such as crushed ceramic monolithic autocatalyst, catalytic diesel particulate filters or catalyst for heterogeneous processes on different carriers.
Known methods for producing precious metals include cupellation, hydrometallurgical leaching and thermal decomposition and/or recovery. Known thermal system that uses a plasma arc, which was used for extraction of platinum group metals. A high-temperature plasma arc is a heat source of great power and versatility, combining the heat from the plasma arc stability and control of the gas flame.
In furnaces with submerged arc (SAF) as a means of electricity used graphite electrode in direct contact with the melt. Graphite electrode is very large due to the high currents used and therefore requires heavy equipment to lift and move. This leads to excessive consumption of graphite, about 20 kg/MW·h of These furnaces operate in periodic mode, and supplied raw materials situada to get the proper resistivity/the chemistry of the slag, since the energy supplied to the process through resistive heating.
US 468963 discloses a method of extracting platinum group metals from various types of raw materials, and for overheating the top layer of slag used a plasma torch with a temperature between 5000°C and 10000°C to accelerate the binding material reservoir through improved modes of fluid flow. This "hot zone" produces extremely localized heating and boiling, and vesbaltarve and mixing up the molten contents of the furnace. The document says about small "particles" of platinum group metals and the material of the collector, suspended in the slag, and the role of fluidity in their aggregation. These individual phases aglomerados separately and migrate, become bound to each other at the base of the container.
Thus, there is a need for a method and/or apparatus that will improve the recovery of precious metal or at least mitigate some or all of the problems associated with the prior art, or will give best alternative.
In the first aspect of the present invention provides a continuous method of obtaining a composition which is rich in precious metals, raw material, including:
(i) heating the raw material in a plasma furnace with the formation of the upper layer of slag and a lower layer of molten metal;
(ii) removing the layer of slag;
(iii) removing the layer of molten metal;
(iv) giving their remote layer of molten metal features to harden;
(v) fragmenting the hardened metal layer with the formation of fragments; and
(vi) extract rich in precious metals composition of fragments;
moreover, the raw material includes containing precious metal material and the metal collector, and the above-mentioned metal-collector is a metal or alloy that can form a solid solution, an alloy or intermetallic compound with one or more precious metals. Raw materials may optionally contain slag-forming materials and/or reducing agents.
In a second aspect the present invention provides rich precious metal composition obtained by the method according to the present invention, the composition comprises an alloy, intermetallic compound or solid solution of one or more precious metals in the crystal structure of one or more phases of the metal collector.
In a third aspect the present invention provides apparatus for implementing the continuous method according to the present invention, containing:
(1) a plasma furnace for heating the raw material;
(2) filling the table.
(3) the device fragmentation to slice the cooled metal layer; and
(4) a separation unit for extracting rich precious metal alloy of the fragments;
moreover, the aforementioned plasma device is a plasma torch and/or electrode, and
when filling this table provides continuous casting molten metal layer with the formation of the hardened sheet.
The separation unit preferably represents a physical separator, such as magnetic separator, the separator eddy current or separator, which acts on the methods of mineral separation and chemical separation. Optionally, the apparatus may further comprise one or more buckets to hold the layer of molten metal and/or transfer at the casting table.
The plasma device is preferably one or more plasma torch and/or electrode. The preferred electrode is a graphite electrode. Plasma torch can be used in conjunction with electrodes. Most preferably, only the use of plasma torches or plasma torches. Filling the table provides casting molten metal layer with the formation of the hardened sheet.
The method according to the present invention is designed to produce rich in precious metals composition by processing various raw materials. Dragon is installed metals include gold and silver, and the platinum group metals, which will be referred to in abbreviated form as PGM and which include ruthenium, rhodium, palladium, osmium, iridium and platinum. Thus, the platinum group metals are a subset of precious metals. The method according to the invention allows to obtain a separate metals or combinations of two or more of them. Although the following description refers to all noble metals and platinum group metals, the specialist will be clear that the method can be used to extract any of the above metals from raw materials. It should also be understood that this method can be applied to transition metal, or any metal.
It is preferable to apply the method according to the present invention is to extract as platinum group metals and precious metals. Precious metals include the platinum group metals, gold and silver, and other metals, which because of its rarity dictate a high market price. Most preferably the method is used for extraction of platinum group metals. The authors of the present invention have found that the method is particularly suitable for the extraction of platinum group metals, as they are usually present in the waste in very small quantities, and the method is extremely minimize the loss of these metals in Slavyane products.
The raw material from which can be obtained is rich in precious metals, the composition may contain any containing precious metals material. Such materials include primary sources, such as ore, and secondary sources, such as waste from reprocessing, spent catalysts containing precious metals residues from industrial processes and/or processes of care. The method is especially suitable for processing of secondary sources. Suitable materials include, but are not limited to, the autocatalyst, chemical catalyst, petrochemical catalyst, catalyst pharmaceutical, waste electrical and electronic equipment, waste talabalarni coatings, dental waste, electroplating waste and waste jewelry.
To maximize the effectiveness of the method, preferably, a thorough selection of complementary mixtures of raw materials, for example, types of complementary catalysts. Selection and rihtovanie can occur for several reasons, including, for example, providing more uniform raw material. For higher outputs preferred wastes with higher concentrations of platinum group metals, in particular, the catalytic converters.
Metal-collector is a metal or alloy which is able to unite with od is them or more precious metals, preferably forming a solid solution, intermetallic compound or alloy. Preferably, the metal-manifold contains iron, Nickel, copper, silver, zinc, cobalt, or alloys containing them as a main element; more preferably, it contains iron or copper, and most preferably iron. In one variant embodiment, the metal-manifold can be fed into the furnace in the form of two or more forming metal-collector components, i.e. in the form of metal components or in the form of alloys, which are connected, forming an alloy of the desired composition of the metal collector.
Iron due to its low cost, easy availability and strong ferromagnetic properties that allow for easy separation from the non-magnetic residues, is the most preferable as a metal collector, as the main element in the alloy metal collector or as forming a metal-collector component. It is also compatible with the processing included in the optional final stage of refining. The inventors have found that an alloy based on iron, you can develop so that it has a low melting point and was relatively fragile, that helps to stage fragmentation. Copper is preferred because of its low cost, easy availability and ease of separation from the of yellow platinum group and precious metals.
Solid solution is a solution of one or more dissolved substances in solution, all in the solid state. This mixture is a solution, and not the connection because the crystal structure of the solvent remains unchanged when adding dissolved substances, although the lattice parameters can be changed, and the mixture contains only chemically homogeneous phase. The dissolved substance, in this case, precious metals, can be introduced into the crystal structure of the solvent, i.e. the structure of the metal-collector, by substitution, replacing part of the solvent in the lattice, or by introducing, integrating itself into the space between the particles of the solvent. An example of a typical solid solution obtained by the method according to the present invention, presented in the "Examples"section.
Alloy is a combination of two or more components, at least one of which is metal. The alloy exhibits metallic properties. The alloys can be solid solutions, as, for example, in α-brass (an alloy of 70% copper, 30% zinc). However, unlike the solid solution alloy crystal structure of the solvent may change with the introduction of the dissolved substance to separately recognizable phases with different crystal structure, as, for example, in α-β brass (an alloy of 60% copper, 40% zinc) or intermetallics connection, TiAl3. Thus, the alloy can exhibit properties different from the mainstream/solvent component.
Benefit from precious metal forming a solid solution, an alloy or intermetallic compound with the metal-collector, is that it allows you to segregated precious metals from raw materials and to unite in the metal collector. In this case, the metal-collector acts as a secure repository for precious metals. In addition, the metal collector is protected from the gas medium layer of slag. It protects the soluble contents from the reaction gas environment and helps to make the method viable as an ongoing process.
It is preferable to choose a lot of metal-collector in the raw material to the mass of precious metals containing precious metals material calculated on the total weight of these two components. Preferably, the metal-collector ranges from 50% to 99% of the total. More preferably, from 80% to 97.5%, and most preferably from 90% to 95%.
In particular, it is desirable to achieve a balance in raw materials between the number of metal-collector and the amount of precious metals present in containing precious metals. This can be determined by chemical analysis. An important indicator of the balance is the ratio, or relative to the body. The inventors have found that when this ratio provides the concentration of precious metals in the reservoir is less than 10% by weight, the outputs of precious metals are high. However, with increasing concentration, i.e. in particular more than 15% of the precious metals by weight, the degree of extraction of precious metals from containing precious metals raw materials is lower. That is, more precious metals are retained in the layer of slag. It is advantageous to use a large number of metal-collector in relation to the content of precious metals in raw materials.
The raw material may also contain additional additives. These additives include intentional additives, including reductants or oxidants. Supplements reductant, for example, a carbon source, make the atmosphere in the furnace recovery and improve the recovery, while minimizing the loss of precious metals on oxidation.
The choice of specific supplements can help to minimize the amount of slag and increase the efficiency of the method. Preferred additives may contact with undesirable impurities in the layer of molten metal and removed in the slag. The method can also deal with unintentional additives, which comprise raw materials, such as materials, catalysts carriers or chassis elektrooborud the cation. Preferably, unintentional additives minimize.
You can also include additives for formulation development slag. Slag is a liquid mixture of inorganic substances such as ash, flux and other impurities. Additives can be selected after consideration and analysis of the composition containing precious metals material, which should be processed. Suitable additives include fluxes. Fluxes that are not necessarily pre-mix in raw materials, add in raw materials in order to ensure that the resulting phase of the slag will have desirable properties such as low viscosity and high/low density), and/or to make the slag more fluid. The slag preferably has a lower density than the metal collector. The preferred fluxes include sodium oxide (Na2O), potassium oxide (K2O), calcium oxide (CaO), calcium carbonate (CaCO3), silicon dioxide (SiO2), aluminum oxide (Al2O3) and magnesium oxide (MgO), or a combination of two or more of them. Particularly preferred calcium oxide.
The method according to the present invention contains a number of stages, which were marked in Roman numerals. Next they will be discussed in turn.
(i) Raw material served in a plasma furnace for processing, preferably with a controlled speed. The heat from the plasma unit in PE and melts and destroys the raw material. Plasma device (or devices) can be plasma torches or electrodes, or a combination. All references to the plasma(s) of the burner(s) should be understood interchangeable references to the electrode(s). This leads to the formation of two layers: a layer of slag, which can be melted and may contain solid impurities; and a layer of molten metal. Due to the relative densities of the two layers and calm, naturalistic conditions existing in the furnace, the slag lies on top of the metal layer. Characteristics such as density, slag can be adjusted by adding slag-forming additives, such as fluxes.
(ii) a Layer of slag is removed. The slag can be removed from the furnace through the outlet. The slag preferably provide an opportunity to flow from the furnace. This allows you to apply a continuous process. It also has the advantage that you can save gas atmosphere furnace. The slag can result directly in a mold or container for storage, or preferably it is removed or poured onto a chilled casting table. In the prior art there are known various methods of cooling of the slag and its fragmentation. They include air or water cooling, direct granulation in water and mechanical crushing. Depending on the composition of the layer of slag he can later find a useful application, is for example, as an additive for steel desulfurization, or as a filler, or in the manufacture of products.
(iii) a Layer of molten metal is removed from the oven. This can be done by tilting the furnace or the opening of the outlet below the level of the metal layer. Preferably, the furnace was neopositivist, so as to enable tilting of the furnace complicates the design of the plasma system, the supply system and connecting flue gas to the furnace. Such connection may be damaged if it is not to be extremely careful when working. Although attempts were made to minimize the amount of slag, which is keen to remove the layer of molten metal, it is inevitable that some of the final weight of the slag will accompany the metal.
Optionally, the slag can be poured into a bucket or equivalent capacity to move it out of the oven.
(iv) Molten metal from a molten metal layer provide an opportunity to harden. This can occur when pouring the metal into the storage tank or the mold. Preferably, however, for ease of fragmentation, the metal is poured in the filling table and allowed to cool. In a preferred variant embodiment, the filling buffet actively cooled, for example, a liquid (water or refrigerant) or air cooling. Expert in Yes the Noi area should understand that can be applied to other conventional cooling methods. Preferably, the cooler is not in contact with the metal. The most preferred method of cooling the casting table is indirect (indirect) cooling water. Molten metal is preferably formed into a thin sheet to facilitate the process of fragmentation, and preferably select the composition of the metal to make it brittle. Suitable thickness are between 1 mm and 30 mm, more preferably less than 20 mm, and most preferably less than 10 mm, If the sheet is thinner than 1 mm, it is difficult to spread on the filling table. If the sheet is thicker than 30 mm, it is difficult to fragment.
(v) the Hardened metal layer then break (fragment) with the formation of small pieces or chips (chunks), so you can remove the segregated sections of metal. Any entrained slag also break. The resulting crumb consists of a rich precious metal compositions, slag impurities or other impurities. The more may be split or crushed layer, the higher the probability that the slag will be replaced by separation and, consequently, the concentration and purity of extracted rich in precious metals composition will increase. The preferred particle or fragment obtained(th) in the fragmentation process, has the diameter less than 10 mm, preferably less than 5 mm, and most preferably less than 1 mm, the Preferred diameter is between 100 microns and 1 micron.
(vi) Crumb or fragments, consisting of rich precious metal composition, separated from the fragments containing undesirable material, such as slag, using the method of separation. The preferred method is magnetic separation. Can be used with other types of separation, including physical separation methods such as filtration, chemical separation, beneficiation of minerals, the separation of the sieve and separation by density, preferably in combination with magnetic separation. You can take more than one of these methods of separation. The term "magnetic" is used here in its broadest sense and includes ferromagnetic separation, and also covers the separation of eddy currents.
Ferromagnetic separation can be carried out using a magnetic tape or a separate magnetic capture. The apparatus may be ferro - or electromagnetic. Ferromagnetic separation is based on the use of ferromagnetic metal collector. Namely, iron, cobalt or Nickel, or their alloys. If you are using magnetic sorting belt, rich in precious metals, the composition is retained on the tape, and the force of gravity causes the fragment of the impurities to fall. The composition may be extracted by precession on the non-magnetic part of the tape or scraping. Alternatively, the magnetic part of the fragments can be raised with the first nonmagnetic tape on the overlying tape. This non-magnetic impurities remain in place. Suitable apparatus for this division shall be known to the specialist.
The separation of the eddy currents is widely used for separation of aluminum from mixed waste ferrous and non-ferrous metals. Suitable apparatus for this purpose must be made known to the specialist. In the separator on the basis of eddy currents rapidly rotating magnetic rotor placed inside a non-metallic drum which rotates at a much lower speed. This gives the change of magnetic flux at the surface of the drum, which is driven pulley for a conveyor belt that carries the flow of mixed materials. When the conductive metal particles are carried by the conveyor belt over the drum, passing through the magnetic field causes particles in them currents. Since the particles have a random shape, no current can flow in them orderly. Currents tend to curl, or saaritsa inside them, hence the name "eddy current".
The effect of these eddy currents is the induction of the secondary magnetic field around not containing iron particles. This field interacting the with the magnetic field of the rotor, the resulting joint driving and repulsive force that literally throws the conductive particles from a stream of mixed materials. This repulsive force in combination with the speed of the conveyor belt and the vibration provides a means of efficient separation. Ejected particles, which contain a wealth of precious metals composition, are held.
Since the magnetic attraction induced in the iron-containing metals in mixed flow, stronger than the vortex effect, it may be necessary to carry out the first stage of magnetic separation, if the metal-collector is not containing iron, but there are iron-containing impurities.
Can also be applied to other methods of separation used for enrichment of minerals, such as classification, flotation and otmuchivanie. Methods chemical separation, including the dissolution can also be used to separate metal collector from slag.
Any slag, obtained by partitioning can be combined with overflow slag and used for other known purposes.
In one embodiment, the embodiment is rich in precious metals, the composition can be reused in the process as a metal collector in order to increase the concentration of precious metals in the composition. Such a multi-pass process is fully the advantage of he gives a more concentrated product at lower current processing costs, without compromising technical levels of extraction of precious metals and reduce the loss of metal-collector to waste. When the concentration of precious metals rich in precious metals composition reaches 10%, it is necessary to dilute re-entered the composition of a large number of metal-collector in order to maintain efficiency and prevent the loss of precious metals in the slag.
In one variant embodiment, the slag can be reused in raw materials as containing precious metals material. This recycling of slag is optional and provides a further opportunity to extract precious metals, which otherwise would be lost from the system in slag removal. Re-entered the slag may also act as contributing to the melting of the additive.
The term "rich in precious metals composition" is used to indicate that the composition obtained by the method according to the present invention, was enriched by precious metals. That is, it contains a higher concentration of one or more precious metals than the raw materials that are introduced into the oven.
As an optional further step in the method (step vii), rich in precious metals, the composition which can be subjected to further refining, in order to obtain one or more essentially pure precious metal or alloy containing an increased weight percentage of one or more precious metals.
The authors of the present invention unexpectedly found that the higher the degree of extraction of precious metals can be achieved through the use of a plasma torch for heating the raw material. In particular, moving the torch over the surface to ensure an even distribution of heat content in the furnace (raw materials, slag and molten metal), improves the output. The inventors have found that minimizing the appearance of hot spots and turbulence in the content promotes the release of precious metals from raw materials in the metal layer. Indeed, the method according to the present invention preferably eliminates hot spots and promotes a calm, aturbulent conditions in the layer of slag or metal. That is, the method according to the present invention preferably eliminates the formation of excessively overheated areas in the contents of the furnace.
The formation of the hot zone and associated turbulence in the contents of the furnace, as in the US 4685963, leads to the loss of platinum group metals in the gas phase due to the formation of volatile oxides and chloride compounds. This impairs technical degree retrieve.
In addition, plasma heat the layer of slag reduces the amount of slag. This may result in the increase in the density of the slag. The volume of slag is minimized also by reducing the amount of slag additives introduced into the raw material for fluxing. The additive is preferably contained in a quantity from one Quad to one tenth, and most preferably one-sixth of the mass of raw material. The presence of a reduced amount of slag unexpectedly reduces the content of precious metal in this layer. In traditional furnaces with submerged arc according to the prior art due to the relatively large mass of the formed slag and periodic mode of operation, the extraction rates are low, and many precious metal is lost in the slag. Submerged arc cannot be precessional above the slag to distribute the heat.
In addition, the use of more uniform heating of the contents of the furnace allows the use of a continuous process. The process is continuous in that the plasma torch or burner can be maintained continuously operating heating the contents of the furnace. By increasing the level of material in the furnace slag is poured from the furnace, and the metal layer increases in volume. When the oven will be enough metal, metal released from the bottom of the furnace. You can then enter additional raw materials to replace released from the furnace material until the level of the slag reaches a sufficient ur is una, for example, the point of overflow, and the process can be repeated. Thus, although the amount of material in the furnace is changed, the process is cyclically continuous, and the plasma torch can keep working. The metal preferably is removed from the furnace portions. Alternatively, in less preferred variant embodiment, the metal can also be removed perennial stream.
The application of continuous process eliminates the need to provide a furnace of the opportunity to cool down between downloads. The design of furnaces for continuous process eliminates the problem of formation of stagnant zones. Furthermore, since the plasma burner is supported working, the layer of molten metal remains molten, when it is removed from the furnace, which prevents clogging of the outlet valve. Continuous operation of a plasma torch means that the oven does not lose heat, and energy is not lost in vain to bring the oven back up to temperature. This saves energy, allows to obtain a higher total technological outputs (i.e. the number of processed raw materials) and/or allows you to use a higher time of stay.
The authors of the present invention have found that the degree of extraction in the method can be analyzed as a phenomenon of separation/distribution phases. Optimized extent of the treatment can be obtained through the formation of in-situ and/or dispersion uniformly heated layer of slag and molten metal collector. This leads to a higher output than is usually obtained when applying focused heat source of high intensity, and gives a homogeneous melt fluidity. This separation of precious metals can be achieved by selecting suitable ingredients of raw materials, careful heating, knowledge obtained phases and their associated interactions. That is, the choice of material collector, temperature and any additional additives can be finely adjusted depending on the desired(s) precious(s) of metal(s).
Measure phase separation is set by the separation factor/distribution (P). It gives a measure of the efficiency of the extraction process. In this context:
Metal-collector in the above formula corresponds to the layer of molten metal. The separation factor/distribution, which can be measured for each individual metal or average in precious metals, is preferably greater than 400, more preferably greater than 800, and most preferably greater than 1500. For determination of the concentration necessary practical study of the content of platinum group metals in layers, and this can be done by conventional methods of chemical analysis, which should be known to the specialist. The strict definition of the coefficients is and distribution would also have the data for a given composition of one layer.
Preferably, the plasma burner, if she focused on the raw material gives the heat more than 1000°C. This minimum temperature required for complete dissolution media containing precious metals material. This temperature preferably is between 1100°C and 2000°C, and most preferably between 1200°C and 1600°C. Is applied, the heat helps to keep the contents of the furnace melted by reducing the boil and intense convective currents in the layers formed in the furnace. This improves the deposition of precious metals in the metal-collector and improves technical degree retrieve.
The plasma device used in the method and apparatus according to the invention may be a plasma torch, or a graphite electrode. In one embodiment, the embodiment is used in more than one plasma device, and it can be independently torch or electrode. The specialist must understand that when the description says plasma burners, you can replace the electrodes. In all variants of the embodiment preferably uses a plasma torch.
Plasma torch used in the method according to the present invention, are used for heating and melting the contents of the furnace. Can be used one or more burners. If you are using only one burner, it can p is edocfile to precessional above the surface of the contents of the furnace. In particular, it is preferred that the burner or burners were precisionenemy and adjustable in all three dimensions. This makes it possible for even heating and promotes uniform heat and fluidity of content, while maintaining the layer of metal in its molten state. This improves the separation.
In one variant embodiment, the apparatus may include working as the plasma torch, and, optionally, one or more backup burners. The use of a number of burners provides improved reliability, availability, and serviceability. If more than one burner, they can be fixed or mobile. In particular, the preferred burned, which are adjustable by the angle of precession and height.
The plasma burner can operate in modes arc direct/indirect action. The most preferred arc direct action; this means that the arc is electrically transferred to the object to be processed, which is energetically more efficient. The arc passes from the cathode through the nozzle orifice to the anode, as it represents the path of least resistance. The burner can operate on direct current, alternating current at the line frequency or radio frequency; as such they are known under the designations dc, ac or rf-burner, respectively. P is impactfully plasma gas is argon or any other inert gas. To the plasma-forming gas may be added other gases to improve thermal efficiency and to modify the chemistry of the arc.
Furnace chamber may be a conventional oven, which is known in the prior art. However, preferably, when the furnace is indirectly cooled by water and has a refractory lining hot working party. The furnace body may be made mainly of steel with copper heatsinks and/or refractory metals, especially in areas of high temperatures. The outer surface of the furnace preferably is cooled to provide a temperature profile, which leads to the formation of the inner protective cover/nastily, which minimizes the wear of the refractory material. The cooling can be performed with water or other cooling, including air. Preferably, the furnace is adapted for use with a fully adjustable plasma burner or burners.
When selecting precious metals from containing precious metals materials important days of your stay. Preferably, the materials are held in the furnace for at least 5 minutes, more preferably 20 minutes, and most preferably 30 minutes or more. A longer time of stay result in a slightly higher degree of extraction, although this comes at the expense of lower speed, which can be processed raw materials. To the floor is to build a good performance, preferred is the maximum time of one hour.
Conditions in the furnace may be oxidative or reductive. Preferably this reduction conditions, as they improve the technical degree of extraction of rhodium and palladium. Restorative conditions promotes the inclusion of carbon in the raw material composition. This can be as a Supplement or as part containing precious metals material.
In a preferred variant embodiment, the furnace operates at a negative pressure (below atmospheric). This minimizes the amount of dust in the exhaust gas due to physical and/or chemical mechanisms of entrainment, minimizes the penetration of air, and also provides reducing conditions. This maximizes the degree of extraction of palladium (Pd), which otherwise usually worsens due to losses on oxidation. The pressure is preferably less than 1 PA, more preferably between 1 PA and -45 PA, most preferably from -25 to -35 PA, ideally -30 PA.
In traditional ovens use high negative pressure of approximately -300 PA. Consequently, a large amount of platinum group metal is lost from the surface of the slag in the system flue gases. Although part of it may be returned as dust filters, it requires a filter and reduces the concentration of precious m is the metal in the composition of the metal collector of the present invention.
Filling the table used in the present invention, provides a smooth surface on which can be cooled, a layer of molten metal with entrained slag. The slag, which is collected from the furnace separately, preferably overflow, you can either be cooled on the casting table, either directly cooled with water. The size and shape of the casting table can be calculated accordingly to allow you to get the preferred product size. Filling the table can be cooled actively or passively. Preferably, the solidification layer of metal and/or slag was carried out through the use of active cooling. Rapid cooling leads to residual stress in the material and associated fragility to facilitate fragmentation. The preferred initial cooling rate of 200°C/s, more preferably more than 300°C/sec. in the case of cooling the layer of molten metal and/or slag layer.
In one variant embodiment, the device contains an optional system fume extraction, designed for processing of all emissions in order to comply with the maximum permissible emissions into the environment, as determined by on-line measurement system CEMS (from the English. Continuous Emissions Monitoring system continuous controlwindow).
Preferably, the system flue gas contains one or more of the following:
- thermocycler, supplemented with complete modulating gas burner and the point of deposition of a solid phase capable of raising the temperature of the furnace gas, plus enough air to provide the oxygen content of 6%, to a temperature of >850°C for more than two seconds. More preferably, above >1100°C for more than two seconds;
- fan for dilution air, supplemented by a frequency inverter to control the addition of dilution air to maintain the gas temperature at the filter at 400°C. Alternatively, may apply regeneration system, waste heat such as boilers for waste heat;
- high temperature filter that uses a ceramic filter elements to remove solid particles from the gas flow, equipped with a phased Autonomous cleaning descending impulse;
- high temperature fan with artificial draught, supplemented by the control of the inverter to spend the entire exhaust from the furnace gas through the treatment system exhaust gas;
- chimney designed in accordance with the methodology D1;
control panel engine comprising three inverter frequency;
- system powder feeder for receiving Packed in bags AK is ivireanul coal, lime or sodium bicarbonate, and for dosed supply of them in the process for the sorption of acid gases and particulate heavy metals;
as the following option to reduce emissions of NOx), the system for reception of NOx-reagent and for dosed supply of it in the process. This is usually called selective non-catalytic recovery (NCSR).
In a preferred variant embodiment of the raw material is subjected to pre-treatment. Pre-treatment may consist of at least one of the following. Each can be conducted individually or in combination with any of the other stages and in any order. The preferred order is that which is shown by the numbering.
1. Sorting and classification
May be the initial treatment to remove items that do not contain precious metals, for example, plastics and rubber included in blocks autocatalysis. Can also be deleted objects that have a size greater than 20 mm or more.
2. Cutting and/or slicing
Cutting and/or chopping are very preferred stages. They are to reduce the average particle size and extract containing precious metals component of the waste. They can also be used for mixing of wastes from different sources. These steps make the process more effectively is active.
The material can be mechanically sieved to select particles with sizes within a specified range. For example, the predetermined range may be from less than 20 mm, more preferably less than 10 mm
Containing precious metal material may be selected and mixed with fluxes, metal-header and/or forming the metal-collector materials in order to obtain the preferred mixture of precious metals in the resulting composition. This can be done by mixing a particularly rich source of precious metals from poorer to provide a uniform/homogeneous raw material. Alternatively, rihtovanie can be done to facilitate the selection of the composition, which is particularly rich in one or more precious metals.
In a preferred variant embodiment containing precious metals material processed prior concentration. It is particularly preferred when the precious metals are present in amounts of less than 100 ppm (ppm), and even more preferred when less than 30 ppm If precious metals are present in quantities above 300 ppm, then pre-concentration of mandatory not required. Waste with more than 10% precious metals are usually pre-n is processed. There are several methods of pre-concentration of precious metals, which should be known to the specialist. These include burning, standard pyrometallurgical smelting, hydrometallurgical dissolution of the matrix or selective leaching of precious metals.
1. Methods of combustion must be known to the specialist. Metal particles can remain in the ash obtained after combustion of the starting material and used at least as part of the raw material.
2. Pyrometallurgical smelting is a form of extractive metallurgy. The main use of smelting is to get the metal from its ore. This includes the extraction of iron from iron ore, usually in the form of iron oxides such as hematite or magnetite, copper recovery and extraction of other non-ferrous and base metals from their oxides obtained by calcination of their sulfide ores. It uses a chemical reducing agent, usually the fuel, which is the source of carbon, such as coke or, in earlier times, charcoal, to change the oxidation state of the metal contained in the oxide. Carbon monoxide or carbon derived from carbon removes oxygen from the oxide, leaving the metal. The carbon or carbon monoxide is oxidized, yielding carbon monoxide and/or carbon dioxide is kind. Since most ores contains impurities, it is often necessary to use a flux such as lime, calcium oxide, to remove co oxide and sulfide impurities in the form of slag.
3. Hydrometallurgical dissolution involves the dissolution of precious metals in Aqua Regia with the formation of their respective chloride salts. Salts of precious metals can be formed by substitution reactions, and these salts in the end reduced to elemental metal using hydrogen.
For example, the rhodium sulfate can be distinguished after the salts were melted together with sodium hydrosulphate and leached with water. The residue can then be fused with sodium peroxide, which dissolves all metals except iridium. And ruthenium, and osmium form camerahouse after the solution was added chlorine. Cityregional OS can then be dissolved in an alcohol solution of sodium hydroxide and separated from any chetyrehokisi ruthenium.
Hydrometallurgical extraction of precious metals from waste tends to become homegrown technology with low capital cost and with poor technical degrees retrieval. Hydrometallurgical/chemical procedure known as the only step in the method of extraction of platinum group metals from waste automobile catalysts. the substantial chemical characteristics of dissolved platinum group metals, their ions are strong oxidants, are easily reduced to metal and is easily hydrolyzed. Thus, they tend to be deposited and to be deposited in unwanted areas, and this may impede the development of a reliable, controllable process.
4. Selective leaching turns metals into soluble salts in aqueous media. Compared to pyrometallurgical operations, leaching easier to implement, but with him and not connected any gaseous pollutants, it is problematic due to the necessity of processing the resulting liquid effluent. The main disadvantage of leaching is its low efficiency caused by the low temperatures of operation, which greatly affects the speed of chemical reactions. The leaching can be carried out by irrigation material diluted cyanide solution which percolates through the ore, dissolving metals such as gold and silver. The solution containing gold and silver, comes out of the ground and going, so that the precious metals can be distinguished.
Hereinafter the invention will be discussed in conjunction with figures 1 and 2 by describing the private variant embodiment of the apparatus. Each and every characteristic of this variant embodiment can be applied individually or together with any of the features set forth in the Isani. Although the following description refers to the platinum group metals, it should be understood that the same method and apparatus can be used to retrieve all of the precious metals.
Hereinafter the present invention will be described in detail with reference to the above example to the accompanying drawings, in which:
figure 1 is a diagram of the apparatus of the present invention;
figure 2 is a flowchart describing a method according to the present invention;
figures 3a and 3b show data on emissions from the process;
figure 4 shows the optical microsemi sample rich in platinum group metals, showing the microstructure of the different areas of the sample, with four separate mikronika show (a) the Central region; (b) detail of (a); (c) a base; (d) surface edge base;
figure 5 shows a typical microstructure of the eutectic of Studite and the corresponding results of energy dispersive x-ray spectroscopy analysis (EDS);
figure 6 shows the results of EDS analysis of the rich iron solid solution near stedicam in figure 5, with the lower figure is a stretched version of the upper body;
figure 7 shows 11 slides detailing a map of the distribution of elements;
figure 8 shows a General view of the eutectic alloy and an iron-rich phase with voids is, partially filled with graphite;
figure 9 shows the likely ledeburite the eutectic;
figure 10 shows the graphite structure; and
figure 11 shows streaks or possible effects of segregation in iron-rich phase.
Hereinafter the present invention will be described in detail. In the following sections in more detail described various aspects and variants of the embodiment of the invention. Each described thus aspect/variant embodiment can be combined with any other aspect/option incarnation or any other aspects/options embodiments, unless explicitly stated the opposite. In particular, any sign that is specified as being preferred or advantageous, can be combined with any other feature or features indicated as being preferred or advantageous.
Figure 1 shows an apparatus 1 for processing of secondary raw materials 3 to extract rich in precious metals composition 5. This allows to obtain refined precious metals 7.
Figure 2 shows the main stages of the method used to extract precious metals. The steps marked with an asterisk are optional. These stages are:
a) obtaining raw material, such as waste autocatalysts;
b) pre-processing the cheese is of avago material 3, such as sorting or selection;
c) pre-concentration of precious metals in the raw material 3;
d) introduction of raw material 3 in an oven chamber 9;
d') the introduction of material collector 10 in an oven chamber 9;
e) processing of raw materials 3 plasma 11 of the plasma device, such as a plasma burner 13. This causes the formation of a layer 15 of slag from the slag layer 16 and 17 of molten metal. The layer of molten metal contains precious metals 7 and the material of the collector 10;
f) a layer 17 of molten metal is removed from the furnace chamber 9 through the exhaust valve 21 near the bottom of the furnace chamber 9. The layer 17 of molten metal flows by collecting chute 23 at the casting table 25;
g) a layer 17 of molten metal is allowed to cool on the filling table 25 with the formation of a layer 27 of metal (not shown);
h) layer 27 of the metal fragment in the crushing apparatus 29;
(i) phase extraction (optional magnetic extraction) is carried out in the apparatus 31 extraction for separation of fragmented layer 27 of the metal to the slag 16 and is rich in precious metals composition 5;
(j) carry out an additional step of refining to get the precious metals 7.
Stages b, c and j are optional. The following steps, which can be optionally included are:
k) recycling is rich in precious what tallamy composition 5 in an oven chamber 9;
d) supplementation 33 (not shown) in an oven chamber 9;
d') the introduction of slag 16 in the oven chamber 9 for recycling;
l) the collection of slag 16, poured from the furnace chamber 9 during continuous processing. The slag 16 leaves the furnace 9 through the exhaust valve 35, which forms an overflow 37 slag;
m) the processing of slag 16.
In a particular variant embodiment of the raw material 3 was applied to the furnace 9 with plasma(s) burner(AMI) and heated to obtain a layer 15 of slag, which is above the layer 17 of metal. The layer 17 of metal contained material reservoir 10 together with metals 7' platinum group, extracted from the containing platinum group metals raw materials 3. The slag layer 15, which contained impurities were removed from the furnace chamber 9 by the method of continuous overflow through overflow 37. Then the slag 16 is cooled (g) and crushed (h).
United metals 7' platinum group metal-collector 10 was removed from the furnace 9 through the bottom discharge outlet 21, to reduce the amount of slag 16, which was fond of. Furnace 9 was designed to allow the slag 16 continuously overflow from the overflow outlet 35. Under normal circumstances overflow discharge outlet 35 had over yourself a protective cover which can be folded to the side for easy access during the examination and release. The outlet 35 for discharging slag m the Glo to be sealed ceramic wool and slag, which stood in the outlet 35. The slag 16 was the best way to clean an oxygen lance. The process of purging continued until, until steady stream of melt and stabilize the temperature of the slag. Note that since the plasma arc plasma torch 13 was still working at the time of release, and the furnace 9, and lance were grounded. Produced the first material is poured into a suitable slampiece, but once established stationary flux, slag 16 was poured into water cooled slag conveyor or water system granulation of slag, to facilitate further processing. The operation of the bonds was carried out with the included plasma, to ensure the supply of heat to the furnace 9, and therefore supported the fluidity of the slag 16 and metal.
Bottom outlet 21 used for the production of metal from the furnace. It was hermetically sealed with clay. After the flow stopped, overflow discharge outlet and insert the blade of a ceramic wool; with bottom outlet is removed the valve and used oxygen lance for burning clay tube to the molten metal in the furnace. After reaching the full flow of the metal from the hole oxygen lance was removed. Molten metal and slag impurities resulted from the furnace lined with refractory bucket type, as a rule is used in the foundry industry. Ladle pre-heated using a gas burner, specially developed for this task, and moved using a forklift truck. After the furnace 9 issued its volume of metal and slag discharge outlet 21 were thoroughly cleaned. The operator quickly scored the outlet 21 clay and installed the valve. Supply was restored to nominal speed, as was only reliable outlet 21.
Metal-collector 10 and fused metals 7' platinum group poured into the casting table 25 for receiving a layer 27 of a metal which has a thickness of 5-10 mm as a discrete mass of admixture of slag 16 is mixed with the metal-collector 10 at the outlet of the furnace 9, it was necessary to crush/grind (h) and magnetic method to extract (i) passionate pieces of metal as the magnetic fraction". Material collector 10 was selected fragile to facilitate crushing and grinding (h)that was required for representative sampling, and for final refining. A large part of the slag 16 extends from the plasma furnace 8 in isolation from the metal collector 10.
Part of the metal pieces again introduced into the furnace (k) in multi-pass process mode to increase the weight percentage of the collected metals 7' platinum group. Rich in platinum group metals whom is ositio 5' then ropinirole, to obtain pure metals 7' platinum group.
Now the invention will be illustrated in the following non-limiting example.
Plasma arc furnace with a diameter of 1.5 m and an inner diameter of 1.5 m was heated using a plasma burner direct action control precessional movement of the burner provided shestikonechnymi robotic arm. Thus, the working end of the burner should truly circular motion at a constant fixed depth from the arch of the furnace. Integrated processing system operated by computer interface Supervisory control and data acquisition (Supervision Control and Data Acquisition SCADA) and was used for processing 2,792 tons monolithic automotive catalyst at a speed of 250 kg/h of catalyst. Representative specialized analysis of the material of the catalyst on the platinum group metals was carried out as follows:
|The catalyst room FIBC||Monolithic catalyst (kg)||Collectively, total (kg)||Pt|
|RIBC 1 bag 1||505,86||505,9||448,5||462||118|
|RIBC 2 bag 3||446,53||952,4||521,5||493||132,5|
|RIBC 1 bag 2||491,45||1443,8||458,5||602,5||124,5|
|RIBC 2 bag 4||474,70||1918,5||1177,5||255||of 211.5|
|RIBC 1 bag 5||502,65||2421,2||1141||238,5||200|
|RIBC 2 bag 6||371,40||2792,6||1200||708||201|
You can specify that the furnace was loaded 2.26 kg Pt, 1.25 kg Pd and 0.46 kg Rh. This waste material was shatavari so that the content of the catalyst, without revealing the volumetric composition of the oxides was 79.7 per cent of the charge. The rest was 12.3% of the flux is, 3.3% of magnetite and 2.7% of the carbonaceous reductant. Thus, the furnace was loaded 3504 kg averaged charge. In the process used precancerous plasma burner to maintain the plasma melting furnace at an internal temperature in the range of 1400-1600°C. the System was based on theoretical energy requirement (TER) 948,5 kW/ton, and when permitted heat loss in the system, this led to the requirement for high power plasma in 439 kW in the processing of 300 kg/h laminated material.
Installation worked 29 hours and gave 3347,1 kg slag, 126,96 kg metal collector, 92,8 kg extracted magnetic method material and 75.3 kg dust from filtration systems. This value is 99.5%, and 3.6%, 2.6% and 2.1% of the mass loaded into the furnace of the initial charge, respectively. The mass of dust was disproportionately high, as it included a lot of sorbent Ca(OH)2loaded into the system fume extraction during processing to reduce emissions of acid gas, i.e. SO2(g). The sorbent was applied with a rate of 0.85 kg/H. in Addition, cross contamination of refractories and/or system is responsible for a small excess of the reporting 100% by weight. Specialized analyses of platinum group metals and the weight percent of platinum group metals in the product metal-collector were as follows:
|Analysis of platinum group metals (mg/kg)||Weight PGM (kg)|
|The extracted magnetic method||5682,50||2382,50||1096,50||0,527336||0,221096||0,1017552|
Technical degree of extraction of platinum group metals was calculated, determining the mass percent of selected platinum group metals in phases of commercial products as a share of net supply, i.e. the content of platinum group metals in charge of the catalysts minus the content of platinum group metals in the dust. Based on this it was determined that the technical degree of extraction accounted for 96.9% of Pt, 99.9% Of Pd and 96.7% Rh. The internal configuration of the furnace is designed to minimize the wetting of materials containment and seepage, as well as the dissolution of the refractory. Analysis of the composition of iridescent slag phase on the platinum group metals has given the following:
|Analysis of platinum group metals (mg/kg)||Weight PGM (kg)|
The calculation of the degree of extraction of the slag based:
Mslag=mass of slag (kg)
MAvtomat=mass of ceramic autocatalyst (kg)
[PGEslag]=concentration of platinum group metals in the slag
[PGEAvtomat]=concentration of platinum group metals in the autocatalyst
This gave technical the degree of extraction of the slag based 98,1% Pt, 94,4% Pd and 97.5% Rh.
The separation factor/distribution for varieties of platinum group metals was calculated as follows:
Thus, for a given melt this coefficient for a mixture of platinum group metals is equal to 893, and the coefficients for Pt=985, Pd=802 and Rh=804. This catalyst material came from the U.S.; however, for native English catalysts, without revealing the identity of the phases and/or composition, typically observed distribution coefficients were as follows:
|The distribution coefficient /number of heat||In the mix||Pt||Pd||Rh|
From this it is clear that the relative masses of the phases and the source/target concentrations of platinum group metals in the resulting phases are very important considerations in the development process.
The method according to example 1 was carried out for the extraction of gold and silver in addition to platinum group metals. The results are summarized in the following tables. All units feed rate of the platinum metals) listed in the table in g/h; all other threads in kg/h
The composition of raw materials
|Threads||The swabs||Catalysts||Copper||Stream EF||Prepared cent sign||Excess supply||Net logon|
|Feed rate (kg)||18,90||11,40||9,00||9,80||49,10||2,10||47,00|
|The content of PM (g)||1895,86||38,78||830,52||0,00||2765,16||118,27||2646,90|
The extracted compounds
|Threads||Retrieved alloy||Retrieved slag||Lost the dust||Gas||Full output|
|Feed rate (kg)||10,02||27,27||0,97||1,7||39,92|
|The content of PM (g)||1,621,34||0,86||140,6||1762,85|
The degree of extraction
|Threads||Balance (g)||Balance (wt.%)||Extraction of PM (%)||Loss PM in slag (%)|
|Feed rate (kg)||-7,08||-15,06%|
The following table summarizes the unique advantages offered by the applicant enhanced plasma melting technology (plasma extraction) compared to other typical competing methods:
|Removing SAF||Hydrometallurgical extraction||Plasma extraction|
|Relative capital costs||High||No data (settings for individual orders)||Average|
|Relative current expenses||High||High||Low|
|The degree of extraction of PGMs (%)||92-96||85-90||>98|
One particular advantage of the present invention is in very good degrees of extraction of rhodium (Rh), which is usually very low, in particular, when allocating conventional separation methods in furnaces with submerged arc.
Next will be estimated emissions based on the best standards for small thermal power plants and the Directive on the incineration of waste (Waste Incineration Directive, WID). With regard to CO emissions(g), they were stable and showed compliance throughout the melting level 13,41 mg/m3. For NOx(g) was observed over almost the full observance of the processing material, and emissions remained stable throughout the heat. Similarly, emissions of SO2(g) kept at a low level, and the feeder lime was sustainable. Observed that the levels of SO2(g) showed excess 1,72% above the requirements of the Agency. This is illustrated in figures 3a and 3b.
The structure is rich in platinum group metals in the solid solution composition obtained in the above example 1, was analyzed metallographically as follows.
ROM metal collector with a diameter of 31 mm and a thickness of 9 mm in the center, which was cast with a sharp cooling water cooled steel casting table, cut in diameter, mounted on a conductive bakelite, finished and polished to a diamond finish 1 μm, then protravel in 2%nitric acid solution in methanol (NITEL)to reveal the microstructure.
The sample examined optically using a microscope (Polyvar Met with digital camera Polaroid™ DMC2. Micrographs were photographed at magnification 100x and 500x. The sample was then examined by SEM JEOL 840A with the conjugate system energy dispersive x-ray analysis (EDS) PGT Imix. For most analyses used an accelerating voltage of 15 kV, but the maps of the distribution of elements was removed using an accelerating voltage of 25 kV, so you was the use of radiation platinum L. This excluded the use of platinum M that overlaps with the emission of phosphorus K, however, distribution maps, based on the phosphorus K, contain contributions from platinum L.
Fig. 4a shows the Central region, typical for the General microstructure of the sample. The microstructure contains flakes of graphite (black)that look-shaped sang typical samachisa cast iron, around which is formed a dendritic phase (dark gray) and dendritic phase (light grey).
Under higher magnification, Fig. 4b, scaly graphite is completely surrounded by dark grey etching phase, which contains several internal veins, possibly due to recrystallization with the formation of the cellular structure, see Fig. 11. At first glance this phase was considered to be indistinguishable perlite, but actually it is a solid solution of iron, probably the austenite, but it is possible and ferrite. Dendritic phase shows a typical structure ledeburite eutectic characteristic cast with a sharp cooling of white cast iron. Later analysis revealed that the light grey phase was a eutectic iron-carbon-iron phosphide, stedet.
The area of the base, Fig. 4c, which, as should be expected, had a higher cooling rate, detects slightly more subtle structure of graphite and slightly lower the dendritic eutectic. Mikros is ructure in a free corner area, Fig. 4d, similar to the microstructure with Fig. 4a. In General, large changes in the microstructure throughout the sample no.
This is an unusual microstructure, as it apparently contains a primary graphite, not cementite, although she was cast with sharp cooling. The probable sequence of solidification of the following: 1) graphite, 2) solid solution of iron, 3) eutectic.
Cast iron can be difficult to prepare, and there is evidence that the disappearance of graphite from the surface, and the resulting holes filled with debris from polishing. However, despite these artifacts, microsemi are significant in relation to the microstructure.
Fig. 5 shows a typical microstructure of the eutectic of Studite and the corresponding EDS analysis. The latter shows that it contains mainly iron and phosphorus with small quantities of other elements in solution.
Fig. 6 contains two charts. The latter is a stretched variant of the first. This figure shows the results of chemical analysis neighboring rich in iron solid solution. This phase contains a high concentration of silicon, which is a ferrite stabilizer and promoter of education graphite. Platinum metals dissolved in this phase with a higher concentration than in Studite. Despite the high content of silicon, it is expected that the Aza represents the austenite. This is because there is carbon, which is equal to the weight acts as a more powerful austenite stabilizer than silicon, which acts as a stabilizer of the ferrite. Platinum metals are austenite stabilizers, and in this phase is the absence of any transformational structures, as would be expected due to the rapid cooling rate (carbon would be rejected from austenite to martensite, bainite or perlite). It is unlikely that the ferrite is in direct contact with the graphite without the presence nearby of some cementite, therefore, the most plausible explanation of this phase is that it is residual austenite, preserved due to the high content of carbon. Internal venation of this phase, as seen in Fig. 4b also shows that this phase is a solid solution, probably in the metastable state.
Fig. 7 shows a map of the distribution of elements for the area proposed austenitic-Steganos eutectic, shown on micronance bottom right. Compounds in each frame, from left to right in descending ranks are: Fe, Si, P, Pd, Pt, Rh, Cr, Ni, V and C. the Main conclusions that can be drawn from these figures is the phase in which predominantly focus each element.
You can clearly view the e l e C the silica is concentrated in the solid solution of iron, phosphorus, chromium, vanadium and carbon is concentrated in Studite. Palladium, which is, apparently, the most common of platinum metals, are clearly concentrated in the iron-rich phase together with platinum, and hence, probably, rhodium plated.
Fig. 8 shows two distributions of dendritic eutectic and areas where graphite has partially disappeared. The low atomic number of carbon leads to the fact that the remaining graphite looks dark, although some of the voids were filled with debris polishing.
Fig. 9 shows the area, which probably contains ledeburite the eutectic austenite-cementite plates of cementite in three orthogonal orientations.
Fig. 10 shows a typical structure of graphite, confirming that the dark phase is graphite, and Fig. 11 for more detail, showing the venation in the proposed austenitic phase.
The binary system between the iron and the elements in solid solution, such as silicon, usually have a wide range of curing under normal conditions of casting and tend to detect significant effects of segregation. This could happen in a very small scale due to experience this sample rapid cooling.
Measuring the hardness of the same cast with the sudden cooling of the sample gave 253, 258, 258 and 275 units HV0. These values are those which could be expected from gray cast iron containing austenitic structure, reinforced solid eutectic of Studite, and are typical for high-silicon cast iron.
This is an unusual alloy of the fact that he is an atypical composition, which was cast with a sharp cooling, and although cast iron is a ubiquitous material, non-equilibrium structure of thin profiles have not been studied adequately, as they did not represent a commercial interest. The most likely explanation of the microstructure of this sample is that the high cooling rate caused him to harden, as if he was sameklesim alloy forming the primary graphite spell, then the dendrites supersaturated austenite may as ledeburite eutectic, with the ultimate rich in phosphorus liquid in dendritic spaces, forming a eutectic iron-iron phosphide, stedet.
Platinum group metals appear concentrated in the iron-rich phase in the solid solution, together with silicon.
The retrieval method of the present invention can be optimized for a particular stream containing precious metals waste and at the same time he gives precise control of inventory and very high technical degree learned what I am. The solution is highly effective and is very competitive from a commercial point of view and flexible in terms of the characteristics of waste streams. All this is achieved with minimal environmental impacts such as air emissions and secondary waste.
1. Method for continuous get rich in precious metals composition of the raw material, comprising the steps:
(i) heating the raw material in a plasma furnace with the formation of the upper layer of slag and a lower layer of molten metal,
(ii) removing the layer of slag,
(iii) removing the layer of molten metal,
(iv) hardening the remote layer of molten metal,
(v) fragmenting the hardened metal layer with the formation of fragments,
(vi) extract rich in precious metals composition of these fragments,
when this raw material includes containing precious metal material and the metal collector, and the above-mentioned metal-collector is a metal or alloy that can form a solid solution, an alloy or intermetallic compound with one or more precious metals.
2. The method according to claim 1, which contains precious metals raw material contains one or more materials consisting of autocatalyst chemical cat who lyst petrochemical catalyst, catalyst pharmaceutical, waste electrical and electronic equipment, waste talabalarni coatings, waste foundry, galvanic waste processing and/or finishing metals, jewelry waste and/or waste jewelry and dental and/or medical waste.
3. The method according to claim 1, wherein the raw material further contains at least one flux selected from boron trioxide, calcium oxide, calcium carbonate, sodium oxide, potassium oxide, silicon dioxide, aluminum oxide and magnesium oxide, including mixtures of two or more of them.
4. The method according to claim 1, wherein the metal-manifold contains iron and/or copper.
5. The method according to claim 1, in which stage (i) the separation factor/distribution, determined by dividing the concentration of precious metals in the layer of molten metal on the concentration of precious metals in the slag layer is 500 or more.
6. The method according to claim 5, in which step (i) the separation factor/distribution, determined by dividing the concentration of precious metals in the layer of molten metal on the concentration of precious metals in the slag layer is 1000 or more.
7. The method according to claim 1, in which the furnace includes one or more plasma device, and referred to eliminate the STV is a plasma torch or electrode, which provides a temperature of from 1200°C to 1600°C in a furnace, and the device is precessional on the contents of the furnace.
8. The method according to claim 1, wherein the remote layer of molten metal is poured in the filling table for his cure.
9. The method according to claim 1, in which the solidification of the remote layer of molten metal is carried out at an initial cooling rate of at least 200°C/s
10. The method according to claim 1, in which the fragments obtained in step (v), have an average particle size from 10 cm to 100 microns.
11. The method according to claim 1, wherein step (vi) is carried out by separation of eddy currents or magnetic separation.
12. The method according to claim 1, in which at least part is rich in precious metals composition re-injected into the process as a metal collector.
13. The method according to claim 1, in which the precious metal contains one or more platinum group metals.
14. The method according to claim 1, which further comprises a step (vii) refining rich in precious metals composition for one or more precious metals.
15. Rich in precious metals composition obtained by the method according to any one of claims 1 to 13, containing alloy, intermetallic compound or solid solution of one or more precious metals in the crystal structure of one or more phases of metal-it is lectora.
16. The composition according to item 15, in which the metal-manifold contains iron and/or copper.
17. Apparatus for continuous get rich in precious metals composition of the raw material by the method according to any one of claims 1 to 14, containing:
(1) a plasma furnace for heating the raw material,
(2) filling the table,
(3) the device fragmentation to slice the cooled metal layer, and
(4) a separation unit for extracting rich precious metal alloy of the fragments,
moreover, the plasma furnace has an input and at least one output, one or more plasma device for heating and performed with removal of slag,
moreover, the aforementioned plasma device is a plasma torch and/or electrode, and
while filling the table is made with the possibility of continuous casting and removal of the layer of molten metal with the formation of the hardened sheet.
18. The apparatus 17, in which the furnace is made continuously indirectly cooled by water and has a refractory lining hot side.
19. The apparatus 17, in which the plasma device is performed using a gas containing an inert gas to create a plasma arc, which can be adjustable to focus on the surface of the contents of the furnace.
20. The apparatus 17, in which the separation unit is a magnetic separat the rum or the separation unit by the eddy currents.
SUBSTANCE: method of demercurisation of waste luminescent lamps comprises destruction of lamps and vibratory cleaning of lamp breakage from luminophore. At that the destruction of lamps is carried out to the glass particle size of no more than 8 mm. After the destruction of luminescent lamps the lamps bases are separated from the glass on the vibrating grate and removed to the collector which is sent to demercurisation- annealing electric furnace. The heat treatment of bases is carried out at a temperature up to 100°C and the holding time of at least 30 minutes. Division of luminophore from the glass is carried out by blowing it in the counterflow-moving system "broken glass-air" under the conditions of vibration.
EFFECT: increased efficiency and energy saving of recycling luminescent lamps, cost reduction and simplification of disposal technology.
SUBSTANCE: method of pyrometallurgical extraction of silver from secondary lead-bearing stock comprises stock furnacing in two steps. First, lead-bearing stock is furnaced at 1150-1200°C, the melt being cooled to 400°C at the rate of 1950°C/h to 2050°C/h. Then, the melt is heated from 400°C/h to 500°C/h to 1150-1200°C to remove the yellow lead from silver surface.
EFFECT: higher yield of silver.
1 tbl, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to cleaning of silver-bearing materials by hydrometallurgy processes, for example, scrap and wastes of microelectronics. Proposed method comprises dilution of silver-bearing material in nitric acid, addition of sodium nitrate to nitrate solution at mixing, extraction of silver salt precipitate and pits treatment to get metal silver. Note here that after addition of sodium nitrate the reaction mix is held for 1 hour to add sodium carbonate or bicarbonate to pulp pH of 8-10. Free silver salt precipitate as silver carbonate is separated from the solution by filtration. Sodium nitrite and carbonate or bicarbonate is added in the dry form. Note here that sodium nitrite is taken with 25% excess of stoichiometry.
EFFECT: higher purity and yield, simplified process.
2 cl, 2 ex
SUBSTANCE: invention relates to hydrometallurgy of scattered elements, particularly, to extraction of bismuth and germanium from secondary stock sources, in particularly, to extraction of bismuth and germanium from oil-abrasive wastes of bismuth orthogermanium crystals production. Proposed method comprises hydrochloride-acid leaching of bismuth and extraction of bismuth from the solution by electrolysis. Said hydrochloride-acid leaching is performed with addition of surfactants to the solution to produce abrasive-germanium-bearing precipitate. Germanium is extracted from said precipitate by distillation of tetrachloride germanium in vapours of hydrochloric acid. Said surfactant represents the commercial mix of oxyethylated alkyl-phenols of commercial grade "АФ" 9-6 at the concentration of 0.01-0.1 wt %.
EFFECT: simplified low-cost process, higher yield.
2 cl, 1 ex
SUBSTANCE: processing method of zinc-containing metallurgical waste involves mixing of waste with coke fines, pelletisation of charge and further performance of a Waelz process in a tube-type furnace. Besides, calcium hydroxide in the amount of 20-30% of silica content in the charge and coke fines with the size of less than 1 mm in the amount of 13-17% of the charge weight are added to the charge at mixing. Charge pelletisation is performed so that granules with the size of 2-4 mm and humidity of 10-12% are obtained. Waelz process treatment is performed at the temperature of 900-1000°C.
EFFECT: improving furnace capacity and reducing flow rate of coke fines of zinc-containing metallurgical waste, for example dusts of electric-arc furnaces.
2 cl, 1 dwg, 5 tbl, 5 ex
SUBSTANCE: method involves separation of a cable into electrical strands in a polymer sheath, steel wire and processing of steel wire pieces into reinforcement elements and with that, separation of steel wire from the electrical strand in the polymer sheath is performed by cutting of steel wire into pieces as a part of the cable along one or two mutually opposite located constituents of the cable by means of adjustable drive disc knives, bending of the cable on rollers and separation of the remained wire pieces from electrical strands by a cutter, and transportation of wire pieces is performed by a vibrating tray with an annular screw-shaped route; deformation of wire pieces is performed by a gear pair having a tooth in the section of a semi-cylindrical shape so that deformation of wire pieces with rollers is provided.
EFFECT: high processing efficiency of wastes of cable products and production of finished products of improved quality, which is suitable for being used in construction of residential and industrial sites.
SUBSTANCE: invention refers to an area of secondary production of non-ferrous metals. An extraction method of cadmium and nickel from used alkali accumulators and batteries involves chemical treatment of waste alkali accumulators and batteries with ammonium chloride by passing through them of condensed vapours of heated solution of ammonium in water with dilution of cadmium and nickel oxides and formation of solutions of cadmium and nickel ammoniates, extraction of solutions of cadmium and nickel ammoniates and their heating with decomposition into cadmium and nickel hydroxides, deposition of cadmium and nickel hydroxides and separation of the obtained deposit from the solution, heating of the solution till evaporation, its condensation and passing of the obtained condensate through the rest mass. The solution separated from the deposit at chemical treatment is tested for cadmium and/or nickel ammoniates available in it by trial action on it with sodium or potassium sulphides, and the above test is repeated till there are no cadmium and/or nickel ammoniates in the solution.
EFFECT: invention provides effective extraction of cadmium and nickel hydroxides from used accumulators and batteries, as well as it allows improving environmental safety of the process.
5 cl, 2 ex
SUBSTANCE: method involves electrochemical deposition of lead from alkaline solutions on asymmetric pulsed current with variation of the periodic sequence of packets of positive n+ and negative n- current pulses, wherein the number of pulses in a packet is selected from n+=20 and the interval 1≤n-≤10.
EFFECT: high degree of extraction of lead from alkaline solutions, low costs, environmental safety and wasteless production.
SUBSTANCE: processing method of slurries of galvanic productions involves leaching of heavy nonferrous metals by means of a sulphuric acid solution with further separation of a solid phase from the leaching solution by clarification and filtration, selective sorption of ions of heavy non-ferrous metals so that cathode deposits of zinc, copper and nickel are obtained from strippants. Before the solid phase is separated, to the leaching solution there added is flocculent - copolymer of vinyl ester of diethanol- or monoethanol amine with acrylate or methacrylate of sodium or potassium.
EFFECT: increasing settlement and filtration speed, and reducing the content of suspended substances in the leaching solution.
3 tbl, 1 ex
SUBSTANCE: concrete recycling plant comprises a screen, an electromagnet and a system of water treatment, and also three technological chains. The first chain is a preparatory one and comprises hoppers for storage of mixtures, concrete, bricks, asphalt delivered by motor transport. The second chain is technological and comprises a plant for screening of heavy metal, the electromagnet for its trapping, a plant for sifting of sand and its storage into a hopper as a filler and a crusher for separation of concrete pieces from reinforcement joined with the second electromagnet. The third chain is a finishing one and comprises a reserve hopper connected with an impact-reflecting mill connected with the third electromagnet, and also comprises two screens connected with a system of water treatment comprising a mixer with a unit of wood chips and organic components supply, then a unit of fractionating, from where the treated items are sent to a warehouse of secondary fillers. To separate concrete pieces from reinforcement, a jaw breaker is used, comprising an electric motor with a pulley, an eccentric, movable and fixed jaws and a discharge window.
EFFECT: higher efficiency of broken concrete recycling.
3 cl, 2 dwg
SUBSTANCE: invention relates to a metallurgical reactor arranged as capable of supply and cooling of electrodes. The reactor comprises a shell with a side wall and a bottom adapted to contain melted material. The reactor comprises at least one consumable electrode stretching via the shell opening into the melted material, a current-conducting contact clamp arranged as capable of conducting working current to the electrode and being in contact with the electrode. The current-conducting clamp has at least one internal channel made as capable of cooling medium circulation. The reactor comprises an electric insulating ring arranged between the electrode and the shell opening, besides, the electric insulating ring is made as capable of tight coverage of the electrode and the opening for limitation of melted material flowing out from the shell. The method includes feed of the electrode in the reactor depending on temperature increase in the side wall or the bottom or near them, where the electrode is inserted into the side wall or the reactor bottom, and supply of the cooling water via the current-conducting clamp.
EFFECT: invention provides for reduction of electrodes consumption and prevention of melt flowing out of a reactor.
8 cl, 3 dwg
SUBSTANCE: proposed method comprises placing mix material into autoclave, heating it, initiating reduction reaction by firing mix material, its melting to produce refractory metal ingot, and unloading finished product. Reaction mix material placed in autoclave, said material is heated directly in autoclave. Autoclave is placed in tightly closed pit representing a straight flow tube with running water to cool down autoclave housing before firing reaction mix material. Mix material is heated by autoclave housing heat. Note here that heating time interval is calculated allowing for time of heating autoclave, its transportation, cooling, and firing reaction mix with due allowance for recovery of the housing mechanical strength provided by cooling the housing and increasing gas pressure. Proposed device incorporates tightly closed vertical pit representing a straight flow tube with running water to cool down autoclave housing before firing reaction mix material. Metal tight tank is arranged in aforesaid pit, while its bottom part represent a cone with cover to remove reaction products.
EFFECT: reduced costs.
5 cl, 1 dwg
SUBSTANCE: procedure for production of chemically active metals and reduction of slag consists in supply of reaction charge containing composition of produced metal and metal-reducer into reaction zone and in heating charge for metal reduction. Also reaction charge is supplied into the reaction zone of an internal cavity of a graphite electrode corresponding to an anode. Metal thermal reduction is first made inside the electrode. Further, charge is transferred and at its exit to an end of the electrode into the zone of arcing plasma-chemical and electro-chemical metal reduction is continued forming bath of liquid metal and slag. After that metal is cooled at crystalliser corresponding to a cathode, while slag is tapped into the second crystalliser corresponding to a cathode. Electrolysis of metal-reducer is carried out by means of the second graphite electrode corresponding to the anode. Next metal is supplied to the repeated process of reduction. The device consists of two crystallisers, two electrodes, a case, a mechanical device supplying charge, a hopper and a branch. Notably, the crystallisers correspond to cathodes. Two electrodes correspond to anodes; also the first electrode is made with a central orifice through which charge is transferred to the crystalliser by means of the mechanical device positioned inside the hopper. The second electrode is made solid.
EFFECT: reduced expenditures and increased rate of process and metal purity.
3 cl, 1 dwg
SUBSTANCE: procedure consists in supply of reaction charge containing composition of produced metal and metal-reducer into reaction zone and in heating charge for metal reduction. Also reaction charge is supplied into the reaction zone of an internal cavity of a graphite electrode corresponding to an anode. Metal thermal reduction is first made inside the electrode. Further, charge is transferred and at its exit to an end of the electrode into the zone of arcing plasma-chemical and electro-chemical metal reduction is continued forming bath of liquid metal and slag. After that liquid metal is cooled at the crystalliser corresponding to a cathode. The device consists of a case, of a mechanical device supplying charge containing produced metal and metal-reducer, of a hopper and of a branch for exhaustion and for supply of inert gas. The device is equipped with the crystalliser, connected to a negative pole and corresponding to a cathode, and with the electrode connected to a positive pole and corresponding to an anode. The graphite electrode has a central orifice and an internal cavity for reduction and transfer of charge. The mechanical device is positioned inside the hopper.
EFFECT: increased rate of process and purity of produced metal.
3 cl, 4 dwg
SUBSTANCE: method of pyrometallurgical extraction of silver from secondary lead-bearing stock comprises stock furnacing in two steps. First, lead-bearing stock is furnaced at 1150-1200°C, the melt being cooled to 400°C at the rate of 1950°C/h to 2050°C/h. Then, the melt is heated from 400°C/h to 500°C/h to 1150-1200°C to remove the yellow lead from silver surface.
EFFECT: higher yield of silver.
1 tbl, 3 ex