The method of extracting precious metals from products containing silver chloride, platinum group metals and gold

 

(57) Abstract:

The invention relates to the metallurgy of noble metals and can be used for processing of products containing silver chloride, gold, platinum group metals, base elements predominantly water-insoluble residue Perevozchikov refining industries. The method includes melting a starting material in the presence of fluxes, forming the oxide of the alkali metal, the Department alloy with a predominant content of silver from the dross, the dissolution of the alloy in nitric acid solution, the deposition of the nitric acid solution of hydroxides of metals impurities at PH = 2 to 5, reductive smelting of platinum group metals from nerastvorimogo remainder of the alloy and hydroxides. The method allows to reduce the cost of refining of the alloy, to reduce the content of noble metals in the slag, to do a more thorough cleaning of nitrate of silver solution from impurities of platinum group metals in the process of hydrolysis. 1 C.p. f-crystals.

The invention relates to the metallurgy of noble metals and can be used in the production of silver and platinum group metals (PGM).

In the production of noble Metaline components, including a silver - like metal, and in the chloride form. These products include dust and concentrate dust (CP) generated when cleaning dust-Laden gases pyrometallurgical processing refining production (concentrate dust called the water-insoluble residue of dust resulting from leaching of electrostatic precipitators).

A characteristic feature of these products is that their base is provided with a large number of different base elements and their compounds, the main of which are:

- volatile components (selenium, tellurium, lead, bismuth, and others);

the chlorides of silver and base elements, resulting from the interaction of dust particles with chlorine or chlorinated compounds;

- sooty carbon produced from waste flue gases in the reaction of disproportionation of CO at low temperature;

- silica and other insoluble oxides, which are the most typical components thermoablative charges.

Concentrate dust is characterized by the following noble metal content, %: Pt - 0,08-0,25; Pd - 0,15-0,35; Rh 0.05 to 0.15; Ir - 0,03-0,1; EN - 0,1-0,3; Au 0.05 to 0.15; Ag - 5-15.

The known method the original gearbox with 5-6 times the amount of magnesite powder, firing the mixture at 350oC, leaching the calcine with hydrochloric acid, separating the insoluble residue (N. O.) from chloride solution, leaching N. O. in ammonia water (translated silver ammonia solution and the concentration of PGMs and gold in N. O. ammonium leaching), concentrating, smelting N. O. Chloride solutions obtained when hydrochloric acid dissolution of the calcine, evaporated to the dry salts are calcined and then use along with magnesite lining for mixing with the new portion CP. [RF patent N 2006508 on request N 5027777 from 17.02.92, "a Method of extracting precious metals from the concentrate dust refining production". Authors: golubova E. A., Zolotov A. F.]

The disadvantages of the method-analogue are the long duration of the technological cycle of extraction of valuable components due to the strong dilution of the original concentrate dust magnesite and extremely slow reactions of solid-phase interaction is contained in concentrate dust chloride with magnesium oxide (under the assumed firing temperature), as well as the high cost of evaporation chloride solution and calcining the dry salts.

The closest to the technical nature of the claimed is a method and the NT RF N 2096506 on request N 96113774/02 from 05.07.96, "A method of extracting silver from materials containing silver chloride, traces of gold and platinum group metals". Authors: Lolat S. I., Kalmykov Yu M, Ilchenko, A. and et - B, 1997, No. 32, S. 281]. This method is adopted for the prototype.

In the prototype method, the source material is melted in a mixture with additives, forming the oxide of the alkali metal, to obtain an alloy with a predominant content of silver is separated alloy with a predominant content of silver from the dross and put his purification from impurities by melt blowing dry air in the presence of soda ash, purified silver granularit and dissolved in nitric acid, separating N. O. from nitrate solution of the nitrate solution precipitated hydroxides, hydroxides used for obtaining a concentrate PGM hydrometallurgical means.

The shortcomings of the prototype method:

- the high cost of fire refining alloy with a predominant content of silver;

- the transition of a significant part of the noble metals in the slag in the process of melt blowing air;

- the lack of completeness purification of nitrate of silver solution from impurities IPY during hydrolysis.

The proposed method is obespechivaetsya exception of education rich in noble metals refined slag and a more complete transition of PGMs and gold in the precipitate of hydroxides.

This technical result is achieved by a method comprising melting the source material containing silver chloride, platinum group metals and gold, representing a predominantly water-insoluble residue of Perevozchikov refining industries, in the presence of fluxes, forming the oxide of the alkali metal, the Department alloy with a predominant content of silver from the dross, dissolving silver in nitric acid solution, the deposition of the nitric acid solution of silver hydroxide impurities according to the invention dissolve in nitric acid is subjected directly alloy with a predominant content of silver, precipitation of metal hydroxides impurities are to establish a PH in the range from 2 to 5, obtaining a concentrate of platinum group metals from nerastvorimogo residue metallic silver and hydroxides carried out by reductive smelting. As a flux containing oxides of alkaline metal, use of oxide slag on the basis of silicates of sodium and calcium, resulting in gold production of precious metals, and the charge for melting product containing silver chloride has a composition, wt.%:

The product containing silver chloride - 40 - 60

Okakarara elements, in particular, such as iron, antimony, tin, tellurium, selenium in the process of dissolution of the alloy with a predominant content of silver and hydrolytic purification nitrate solution from impurities.

These impurities base elements (especially, antimony and tin) is formed in the alloy with a predominant content of silver acid phase of the platinum group metals. Upon the dissolution of this alloy in nitric acid PGM concentrate mainly in nerastvorim residue. That part of the admixture of base elements (mainly iron, selenium, tellurium), which moved from the alloy in the nitrate solution, performs the role of a collector (sorbent), contributing to a more complete coprecipitation with PGM precipitate hydroxides in the process of hydrolytic solution treatment.

The optimal interval used pH of doing hydrolytic process of cleaning selected experimentally. At pH less than 2 cleaning nitrate solution from impurities practically does not occur. By neutralizing nitrate solution until pH=2, the formation of substantial amounts of precipitate hydroxides, mainly on the basis of antimony, tin, iron and tellurium, and coprecipitation with them znachitelnoe.u simultaneously iron, copper, selenium and platinum group metals. The increase in pH above 5 is not desirable because it does not give a significant increase in the extraction of platinum group metals in the precipitate of hydroxides, but causes a strong increase of the mass of sediment due to the transition of lead and silver, which reduces extraction nitrate solution silver and complicates the process of getting all precious metals.

In the process of smelting reduction plants hydroxides selected in the process of cleaning nitrate solutions, with the addition of flux, at a temperature of 1200 - 1300oC, base elements partially distills in the gas phase, partially checkouts and PGM together with the impurities of gold and silver form the rich in their content of heavy alloy that can be processed by known methods.

The use of a smelting reduction plants for the concentration of PGM from hydroxides is preferred (in comparison with novosstroitelnaya melting), as it provides a higher recovery of precious metals in heavy target alloy and improves its individual technological properties.

As the oxide slag on the basis of silicates of sodium and calcium, resulting in gold production, contain up to 70% of silicone which is very promising and allows to reduce costs of production. In using slag refining production as fluxes is the ability of silicates of sodium and calcium to enter into reactions of type (1) alkali-thermal recovery of silver from its chloride

2AgCl + 2Na2O SiO2+ CO = 2Ag+ Na2O 2SiO2+ 2NaCl + CO2(1)

Conditions the leaching alloy with a predominant content of silver with nitric acid, the proposed method does not differ from the conditions used in other similar ways. The extraction of silver from the received and cleared PGM nitrate solution may also be carried out by known methods.

Examples of usage.

Example 1. Took 200 g (dry weight) concentrate dust containing: 20,1% of silver chloride, 0.25% for platinum, 0,31% palladium, 0.1% is rhodium, 0,08% iridium, 0,2% - ruthenium, and 0.09% gold, added 200 g of granulated oxide slag on the basis of silicates of sodium and calcium, resulting in gold production, and 44.4 g of calcium oxide. All components of the mixture were mixed, placed in a fireclay crucible and subjected to melting in a laboratory electric furnace at a temperature of 1300oC for 60 minutes.

The fusion received of 62.4 g of the alloy with a predominant content is, to 1.0% copper, 1.0% of iron, 16,0% of the lead, and 1.0% bismuth, about 4.0% - selenium, 6,3% of tellurium, 5.3 per cent tin, and 9.5% antimony.

When melting was obtained 249,0 g slag, containing 0.1% silver, and do not contain PGMs and gold (according to the spectral analysis).

The resulting alloy with a predominant content of silver metallic silver was divided into two equal parts and one of them was subjected to processing according to the proposed method (see continuation of example 1) and the second according to the method prototype (see example 2).

The sample obtained by melting the alloy with a predominant content of silver by weight of 31.2 g was subjected to dissolution within two hours in a solution of nitric acid (64%, 14 M) at a temperature of 80oC, at T:F = 1:1.2, with stirring of the solution. Separated by filtration, nerastvorim sediment from nitric acid solution, washed precipitate a small amount of water, the solution from the washing added to the main solution.

The result was obtained by 60 ml of nitric acid solution, which (according to the analysis ICP) contained (g/l: Pt - 0,083; Pd - 1,30; Rh - 0,167; Ir - 0,467; EN - 0,167; Au - 0,233; Ag - 241,3; Cu - 3,9; Fe - 0,4; Pb - 70,7; Bi - 4,2; Se - 12,5; Those of 13.1; Sn - 1,9.

A lot of nerastvorimogo residue (after drying) was 12.1, Received N. O. is virusesa residue (N. O.) used to prepare the mixture for melt processing. To do this, 12,1 g N. O. added 4.6 g of sodium carbonate and 1.7 g of Corsica, the mixture was mixed, placed in a fireclay crucible and subjected to melting in an electric furnace at a temperature of 1300oC for 45 minutes.

The fusion received 5,09 g target heavy alloy containing (according to spectral analysis): 4,8% of platinum, 4.5% of palladium group, 1.8% rhodium, 1,0% iridium, and 3.7% of ruthenium, 1,5% - gold, 10.2% of silver. The alloy of similar composition may be subjected to refining with the use of known methods. Smelting was also obtained 7.2 g of slag, containing (according to the spectral analysis of PGM and gold.

Nitrate of silver solution was subjected to hydrolytic purification from impurities. To 60 ml of the original solution at a temperature of 60oC was added a solution of alkali (3N NaOH) to achieve a pH of 3.0. The consumption of the alkali solution was 43 ml.

The precipitate of hydroxides, in which the solution turned a large part of the IPY, about 85% iron, 10% copper, 11% lead, 7% bismuth, 40% selenium, 90% of tellurium and 2.1% of silver was filtered, dried and subjected to beneficiation smelting. For this to 2,68 g precipitate hydroxides added 1 g of sodium carbonate, 0.5 g of silicate-sodium glass, 0.3 g of Corsica. The component is within 30 minutes.

The fusion received 0,956 g target heavy alloy containing compared to 8.26 % PGM and gold, 31,3% silver, 31% of tellurium, 10.4 percent selenium, 15.6 per cent lead and 2.1% copper. This alloy may be subjected to refining using well-known methods as the concentrate of platinum metals. When melting was obtained 1.5 g of slag, not containing PGMs, gold and silver.

As the third of the target product, which may be further directed to the deposition of silver by using various known methods, received 100 ml of a solution containing, g/l: Ag - 141,7; Pt - 0,022; Pd - 0,32; Rh - 0,052; Ir - 0,115; EN - 0,053; Au - 0,095; Pb -37,7; Cu - 2,1; Se - 4,5; Te - 0,76; Fe - 0,04; Bi - 2,3; Sn - 1,0.

Thus, the direct extraction of silver nitrate in the solution of the original product - KP when using the proposed method was 95,8% (taking into account run by nitric acid dissolution of 50% by weight obtained by smelting the alloy with a predominant content of silver). Direct extraction of PGMs and gold (in the aggregate) in the target alloys from the original gearbox was 93.6%.

Example 2. Took alloy with a predominant content of silver obtained from the smelting of the concentrate dust (melt conditions, see example 1). The alloy contained, %: platinum - 0,80; palladium - 1.0; rhodium - 0,32; iridium - 0,25; rutina - 9,5.

Alloy with a predominant content of silver in the number of 31.2 g was placed in alongby the crucible, added 20 g of sodium carbonate and subjected to refining smelting in the electric furnace at a temperature of 1150oC. the resulting melt was subjected to the air purge for 30 minutes. After separation of the slag was obtained to 18.6 g of the alloy based on silver, which was subjected to granulation in the aquatic environment. The obtained granulate on the basis of silver had the following composition, %: platinum - 1,02; palladium - 1,18; rhodium - 0,43; iridium - 0,38; ruthenium - 0,91; gold - 0,38; silver - 68,8; copper - 1,3; iron - 0,09; lead - 5,9; bismuth - 0,7; selenium - 4,8; tellurium - 6,9; tin - 1,6; antimony - 2,2.

Received 24.5 g of slag, which contained, per cent: platinum - 0,24; palladium - 0,37; rhodium - 0,08; iridium - 0,04; ruthenium - 0,12; gold - 0,08; silver - 9,0.

The granulate based on silver (18.6 g) was subjected to dissolution within two hours in a solution of nitric acid (64%, 14M) at a temperature of 80oC, with stirring of the solution. Separated by filtration, nerastvorim sediment from nitric acid solution, washed the precipitate with water, the solution from the washing added to the main solution.

The result is a 50 ml nitric acid solution, which (according to the ICP) soda is ACCA's nerastvorimogo residue (after drying) was 6.1, Received N. O. contain, %: Pt - 3,0; Pd - 2,2; Rh - 1,1; Ir - 0,8; EN - 2,5; Au - 0,95; Ag - 6,3; Cu - 1,0; Fe - 0,2; Pb - 3,0; Bi-0,5; Se - 5,8; Te - 12,6; Sn - 4,4; Sb - 5,9.

Nitrate of silver solution was subjected to hydrolytic purification from impurities. To 50 ml of the original solution at a temperature of 60oC was added a solution of alkali (3N NaOH) until reaching a pH value of 5.0. The consumption of the alkali solution was 40 ml

After filtration of the slurry and drying the precipitate obtained 1.85 g of the precipitate hydroxides of metals impurities, %: Pt - 0,27; Pd - 2,65; Rh - 0,26; Ir - 0,54; EN - 0,29; Au - 0,18; Ag - 13,5. In the method prototype this sludge process hydrometallurgical methods of obtaining a concentrate of platinum metals.

As the third target of the product obtained in 86 ml of a solution containing, g/l: Ag - 141,4; Pt - 0,035; Pd - 0,45; Rh - 0,06; Ir-0,12; EN - 0,10; Au - 0,10. This solution according to the method prototype is subjected to electrolysis to obtain refined silver.

Thus, the prototype method of direct extraction of silver nitrate in the solution of the original alloy with a predominant content of silver metallic silver obtained smelting of concentrate dust amounted to 81.1% of. Direct extraction of PGMs and gold alloy with a predominant content in the precipitate of hydroxides of metals impurities (total), was 70.1%, which is considerably lower than when using the proposed method (95,8% and 93.6%, respectively).

1. The method of extracting precious metals from products containing silver chloride, platinum group metals and gold, mainly from water-insoluble residue of Perevozchikov refining industries, including the melting of the source material in the presence of fluxes, forming the oxide of the alkali metal, the Department alloy with a predominant content of silver from the dross, dissolving silver in nitric acid solution, the deposition of the nitric acid solution of silver hydroxide impurities, getting a PGM concentrate from hydroxides of metals impurities, characterized in that the dissolution in nitric acid is subjected directly alloy with a predominant content of silver, the precipitation of the hydroxides of the metals impurities lead to the establishment of pH 2 to 5, getting a PGM concentrate from nerastvorimogo residue metallic silver and hydroxides carried out by reductive smelting.

2. The method according to p. 1, characterized in that as a flux containing oxides of alkaline metal, use of oxide slag on the basis of silicates of sodium and calcium, resulting in affinage composition, wt.%:

The product containing silver chloride - 40 - 60

Calcium oxide - 5 - 15

Slag - The Rest

 

Same patents:

The invention relates to the field of metallurgy

The invention relates to the field of ferrous and nonferrous metallurgy, in particular to non-waste technologies, and can be used for recycling and preparation for transportation of vanadium Solodov from the combustion of any fossil fuels to places metallurgical

The invention relates to the field of metallurgy, specifically to methods of waste produced in cupola wet residue and contained metals

The invention relates to the metallurgy of rare metals and can be used when passing the extraction of osmium in the chemical industry in the processing of chromite chemical type monochromats on sintering technology
The invention relates to a process of preparation and production of briquettes for ore-thermal production of ferroalloys, iron and steel and can be used in metallurgy and chemical industry

The invention relates to ferrous metallurgy, in particular to a method of processing sublimates titanium chlorinators, including the dissolution of obtaining pulp, treatment of the pulp with an alkaline reagent, separating the precipitate of a mixture of hydroxides, the processing solution of an alkaline reagent with getting micaceous iron pigments, filtration, washing and drying

The invention relates to a method for processing inorganic solid waste

The invention relates to the refining of precious metals and can be used in the processing of gold-silver alloys

The invention relates to a method for producing oxides of refractory metals from loparite concentrate

The invention relates to the production of vanadium compounds vanadium and ferrovanadium
The invention relates to metallurgy, and in particular to methods of obtaining manganese and can be used to obtain okuskovannogo low-phosphorus manganese concentrate

The invention relates to the metallurgy of noble metals, particularly to the refining of gold and silver

The invention relates to the hydrometallurgical processing of loparite concentrate
The invention relates to hydrometallurgy of gold and can be used in the recovery of gold from waste, recycled materials, electronic scrap Imperial vodka
The invention relates to methods for separation of rare earth elements (REE) from the secondary concentrates produced during the processing of Apatite

The invention relates to the hydrometallurgical processing of ore concentrates, and more particularly to the processing of loparite concentrate

The invention relates to metallurgy, in particular to the recovery of precious metals from silver flotation concentrates
Up!