Method of reclaiming cyanide from aqueous solutions

FIELD: chemistry.

SUBSTANCE: invention relates to a method of reclaiming cyanide from aqueous solutions, particularly recycled water which contains thiocyanates CNS-. The method involves electrochemical oxidation of thiocyanates. Before electrochemical oxidation, recycled water, which contains from 2 to 20 g/l thiocyanates, is acidified to pH=2-3. Electrochemical oxidation is carried out at current density of not less than 750 A/m2 for 2 to 3 hours while simultaneously letting in air into the solution. The formed hydrogen cyanide is trapped in an absorption vessel with its output ranging from 70 to 80%.

EFFECT: reduced content of thiocyanates in recycled water with simultaneous reclamation of cyanide.

3 dwg, 1 ex

 

The invention relates to electrochemical oxidation of thiocyanate

(CNS-). In particular, the regeneration of cyanide (CN-) from aqueous solutions containing thiocyanates, partial elektrookislenie last.

Aqueous solutions containing significant amounts of thiocyanates are formed at the stage of leaching of sulfide gold ores and may contain from 2 to 20 g/l CNS-. The use of such solutions as the reverse is not possible because of the possibility of its accumulation in the tailings and difficult to use these solutions in technological processes. At a low content of CNS-, less than 0.15 g/l, circulating water is returned in the technological process when this is not possible, it is important to treat such water to MPC with a view to their disposal.

There is a method of neutralization of circulating water from cyanide and thiocyanate ions by calcium hypochlorite. Oxidation to tiantou described by the following equations:

The stoichiometry of these reactions shows that for oxidation of thiocyanates you 4 times more "active chlorine", compared with cyanide. Given the concentration of thiocyanates in solution, this method will require a substantial flow of oxidant is and neutralization. In addition, the disadvantage is the appearance in the water of a large number of chloride ions that have a negative impact on the process. Hypochlorite oxidation it is necessary to maintain a pH of not lower than 10-11 due to the possible formation of CYANOGEN. It also increases the cost of disposal (Zelenev VI, Baryshnikov IVAN, Straneva SM Practice of processing gold ores using cyanide. M. Ed. "Tsvetmetinformatsya", 1968, p.46).

There is a method of neutralization of circulating water from cyanide and thiocyanate ions by hydrogen peroxide. Destructive oxidation of cyanide and rodando hydrogen peroxide allows to achieve significant environmental effect by reducing the salinity of wastewater (I.R. Wilson, G.M. Harris, "The oxidation of thiocyanate ion by hydrogen peroxide", Journal of the American Chemical Society, 82 (1960) 4515-4517).

The disadvantage of this method is the delivery of liquid reagent to place immediate use.

The closest is a method of electrochemical oxidation of thiocyanates with their full decomposition with simultaneous regeneration of cyanide due to partial electrochemical oxidation of CNS-. Electrochemical oxidation of thiocyanates were carried out in an alkaline medium with the use of Ptthe gas diffusion anode and the cathode, generating hydrogen peroxide from oxygen in electrolytic cells with cat is ionoobmennoi membrane without membrane (Kenova T.A., Kornienko V.L. Oxidation of thiocyanates hydrogen peroxide generated in the gas diffusion electrode in an alkaline environment. Chemistry for sustainable development, 10 (2002) 307-311). This method has several disadvantages. The method destroys the thiocyanates to less toxic substances that require significant economic and technological costs. High consumption of electricity coming down on the cost.

The objective of the invention is the reduction of the content of the thiocyanate ions in the circulating water, with simultaneous regeneration of cyanide due to partial electrochemical oxidation of CNS-in the acidic environment to cyanide and Stripping it in a gas atmosphere with subsequent removal in alkaline solution.

The problem is solved in that in the method of regeneration of cyanide from aqueous solutions, in particular from the circulating water containing thiocyanates CNS-including electrochemical oxidation of thiocyanates, according to the invention, before the electrochemical oxidation of the circulating water containing from 2 to 20 g/l of thiocyanate is acidified to pH 2-3, the electrochemical oxidation is carried out at a current density of not less than 750 a/m2within 2-3 hours with simultaneous supply of air into the volume of the solution and capture the resulting cyanide adsorption vessel at its output 70-80%

The technical result is the Ohm, when electrochemical oxidation in acidic environment the thiocyanate is oxidized by reaction

to cyanide and sulfate ion. Released hydrogen cyanide otdovat sealed in a gas phase and then sent to an adsorption vessel with sodium hydroxide, forming sodium cyanide

To select the conditions of the oxidation process of thiocyanates in an acidic environment, experiments were carried out, the aim of which was to determine the influence of current density, the number of missed electricity and Stripping the resulting cyanide on the efficiency of the process of regeneration of cyanide.

To determine the optimal conditions were carried out the following experiments:

1. The choice of the method of electrochemical oxidation

Electrochemical oxidation of thiocyanate can be conducted without Stripping and Stripping cyanide. Oxidation with Stripping involves the process in two stages: 1 - electrochemical oxidation, 2 - blow-off air formed of cyanide adsorption vessel. In the present method the electrochemical oxidation simultaneously with the Stripping. Figure 1. The dependence of the yield of cyanide from the time of electrolysis: 1 - electrolysis SCN-without Stripping; 2 - electrolysis SCN-c the Stripping HCN.

The graph shows the dependence of the output of the cyanide from the time when the different ways of carrying out electrochemical oxidation. Chart data show that electrochemical oxidation with simultaneous Stripping leads to increased release of substance hydrocyanic acid to 64% (kr), two hours of electrolysis, compared with the process without Stripping - 41,5% (kr).

2. The choice of the current density during the electrochemical oxidation

To determine the optimal current density during the electrochemical oxidation of thiocyanates of leachate from the tailings slurries sorption leaching ASIF were selected current density of 750 and 1000 a/m2.

Figure 2. The concentration dependence of thiocyanates and cyanide from the time of electrolysis at different current densities: 1, 2 - 1000 a/m2; 3,4 - 750 a/m2; 1, 3 - residual concentration of thiocyanates; 2, 4 - concentration of cyanide in the absorption vessel.

The graph shows changes in the concentration of thiocyanates and cyanide from the time of electrolysis at a current density of from 750 to 1000 a/m2. The oxidation rate of thiocyanates increases with increasing current density. The initial concentration of rodando was 20,21 g/l residual concentration of rodando was 0.59 g/l for 2.5 hours for a current density of 1000 a/m2and of 4.46 g/l for a - 750 a/m23 hours of electrolysis. The output of cyanide substance 67,7 and 84.8%, respectively. Reduction of cyanide at the current density above 750 a/m2due to the more rapid is the second oxidation reaction of cyanide in the electrolyzer, the increase in speed Stripping (air flow) on the formation of hydrocyanic acid has no effect.

Figure 3. The dependence of the concentration of thiocyanate and cyanide from the time of electrolysis at different current densities: 1, 2 - 1000 a/m2; 3, 4 - 750 a/m2; 1, 3 - residual concentration of thiocyanates; 2, 4 - concentration of cyanide in the absorption vessel

The graph shows changes in the concentration of thiocyanates and cyanide from the time of electrolysis at a current density of 750 and 1000 a/m2. Initial concentration of thiocyanates was 2, 53 g/l For 1 hour oxidation of the residual concentration of SCN-was 0,0038 and 0,059 g/l, and the substance of cyanide of 83.4 and 90,6% at the current density of 1000 and 750 a/m2respectively.

The optimal current density for the oxidation of thiocyanate by Stripping HCN formed with the purpose of obtaining a solution of cyanide is the current density of 750 a/m2. For complete removal of thiocyanate from solution by electrochemical method with Stripping in the form of HCN, and complete oxidation of the remaining thiocyanate, is the current density of 1000 a/m2.

An example of the method

In a sealed electrochemical cell of 10 l put the circulating water containing from 2 to 20 g/l of thiocyanate and acidified to pH 2-3, at current density of 1000 a/m2. The oxidation process of thiocyanates to cyanide is carried out with about the simultaneous supply of air into the volume of the solution. For pressurized pipeline gas phase is sent to an adsorption vessel containing a solution of sodium hydroxide. The process is carried out for 1-3 hours to a residual content of thiocyanate less than 0.1 g/l When the concentration of thiocyanates solution can be used to make pulp. Obtained after electrolytic decomposition of thiocyanates solution is alkalinized and guide in the process. There is a reduction of the content of thiocyanates in the solution of 2-20 g/l to the level of 0.1-0.15 g/L. Absorbing solution contains sodium cyanide concentration of the latter at the level of 5-15%, which is then used in the process to leach gold.

Oxidation of thiocyanates with simultaneous Stripping cyanide can significantly reduce the concentration in the circulating waters. Thus formed during the oxidation of cyanide can with high enough out of the substance (70-80%) to be removed and returned back to the process, while reducing the consumption of oxidants on redistribution decomposition of cyanides and thiocyanates from solutions tailings slurries.

Method of regeneration of cyanide from aqueous solutions, in particular from the circulating water containing thiocyanates CNS-including electrochemical oxidation of thiocyanates, characterized in that before the electrochemical about what iselenium the circulating water, containing from 2 to 20 g/l of thiocyanates, acidified to pH 2-3, the electrochemical oxidation is carried out at a current density of not less than 750 a/m2within 2-3 h with simultaneous supply of air into the volume of the solution and capture the resulting cyanide adsorption vessel as it comes out of 70-80%.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy and can be used at method of cleaning against chlorine of zinc-sulfate solutions, received at sulfuric acid leaching of secondary zinc raw material, containing chlorine. Method includes sedimentation of chlorine-ion in the form of copper-chlorine cake by addition of copper-bearing solution and copper cake, containing metallic copper. In the capacity of copper-bearing solution it is used solution, formed at sulfuric acid leaching of solid residue, received after solution of copper-chlorine cake in solution of sodium hydroxide. Additionally copper-chlorine cake is solved in the solution of sodium hydroxide at concentration 50-75 g/l.

EFFECT: reduction of consumption of flowing copper cake to cleaning of zinc-sulfate solutions against chlorine and reduction of costs for this process.

2 cl, 1 tbl

FIELD: metallurgy.

SUBSTANCE: method consists in diluting material with water and in treating pulp with nitric acid. Further, not dissolved material is separated, washed and chlorinated in hydrochloric acid and pulp is filtrated. Upon filtration hydrochloric acid solution is neutralised; sediment of impurities of non-ferrous metals is separated from solution containing noble metals. Also upon diluting pulp is treated with nitric acid to redox potential of 800-900 mV. Sodium chloride is introduced into obtained hydrochloric acid solution first, then formed silver salt is separated, solution is treated with sodium sulphate and lead salt is filtered off. Further, redox potential of solution is reduced to 300-450 mV by introducing light alloy containing copper for reduction of palladium and its precipitation. Then sediment is separated, and solution is neutralised with alkali; formed sediment containing copper is filtered.

EFFECT: upgraded degree of separation of non-ferrous and noble metals and extracting of silver, copper, and lead into selective product with low contents of platinum metals.

1 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in refining platinum-group metals. A residue consisting of a mixture of hydrated oxides of osmium and ruthenium is saturated with water. The obtained pulp is treated with hydrochloric acid and oxidising agent until dissolution of the residue while heating. The oxidising agent used is hydrogen peroxide or sodium chlorate. Osmium oxide is removed by sucking through an air system. The solution remaining after removal of osmium is filtered, treated with concentrated hydrochloric acid and heated for 2 hours. Ammonium chloride is added and ammonium chlororuthenate is precipitated. The obtained salt is washed from the mother solution.

EFFECT: selective extraction of osmium and ruthenium, shorter duration of the process and reduced consumption of reagents.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to noble metals metallurgy and can be used for reprocessing of different wastes of refining, such as dust-fumes or water-insoluble residues of dust-fumes. Method of products reprocessing, containing chalcogenides of base metals, lead, platinum metals, gold and argentum includes leaching of initial product in solution of caustic soda, separation of received alkaline solution from insoluble residue. Insoluble residue is subject to melting with addition of manufactured products of refining, sodium-bearing flux and carbonaceous reductant. After melting it is implemented grinding of separated bottom heavy phase into the powder and its treatment as a concentrate of refining. Into received during leaching initial products alkaline solution it is added sulfuric acid up to pH=4-6, it is separated laid-down from the solution deposit of hydroxides on the basis of tellurium dioxide. Solution after the sediment separation is again treated by sulfuric acid up to pH=1-2, it is added sodium sulfite and separated laid-down deposit of metal selenium, and mother solution is subject to finishing de-refining.

EFFECT: cost cutting while de-refining of received during the reprocessing solutions.

1 ex

FIELD: metallurgy.

SUBSTANCE: invention concerns metallurgy field. Particularly it concerns receiving technique of nickel and can be used at treatment of efficient solutions of sulfuric acid leaching of nickel. Treatment technique of sulfuric acid nickel-bearing solutions includes its rectification from ferric iron by solution neutralisation till pH=5 and extraction from it nickel. At that neutralisation till achieving pH=4 is implemented by alkali metal hydrate, and further neutralization from pH=4 till pH= 5 - by aqua ammonia.

EFFECT: increasing of nickel extraction from efficient solution of sulfuric acid leaching at its purification from ferric iron.

2 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: method of neutralisation against residual cyanide of liquid phase of tail pulps after sorption of nonferrous metals includes cyanide deposition by reactant in the form of insoluble complex compound. At that in the capacity of reactant it is used pulp filtrate from the process of biooxidation of sulphide gold-bearing concentrate, containing sulfuric acid and ferric iron sulfate. At deposition reactant is used in ratio not less than 10 l of pulp filtrate per 1 m3 of each liquid phase of tail pulps, at finite pH of deposition 6.5-7.5 and time not less than 1 hour.

EFFECT: effective usage at enterprises of non-ferrous metallurgy for treatment of tail pulp of gold-extracting mill from residual cyanide.

2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to method of extraction of at least one metal compound and/or its element out of liquid mixture or out of mixture containing catalyst and/or residuals of catalyst after homogeneous catalysed reaction. The method includes contacting of the said mixture with heteropolyacid or with anion of heteropolyacid, at that volume of heteropolyacid or anions of heteropolyacid consists at least 0.1 of equivalent with obtaining a sediment, at that, this sediment is practically non-soluble in the said reaction mixture and containing heteropolyacid or anion of heteropoliacid and compound of metal and/or its element; the method also includes reduction of the reaction mixture.

EFFECT: upgraded efficiency of process.

41 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: method involves co-sedimentation of admixture-containing solution of americium oxalate on a carrier represented by calcium oxalate, followed by obtaining nitrate americium-containing solution and americium oxalate, with its further calcination to dioxideo. Americium-containing carrier sediment is also calcinated to oxides. Nitrate solution is obtained by dissolving oxides formed during calcination in nitric acid. Americium is extracted from nitrate solution with the help of solid extragent based on diisooctylmethylphosphonate, with further re-extraction. Americium oxalate is obtained by sedimentation from condensed re-extract.

EFFECT: extended range of methods of obtaining dioxide.

3 cl, 3 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to hydrometallurgical methods of processing and deactivation of radioactive waste at rare metal production. The method includes hydro washing away of spent melt of saline spraying filter (SSF), the chlorination process of loparit concentrates, treatment of produced suspension with alkaline reagent, mixing with iron containing shop flush waters, separation of radioactive sediment from the mother solution and transporting of radioactive sediment into a special waste storage (SWS). Prior to treatment with the alkaline reagent the suspension, produced after hydro washing away of spent melt SSF, is mixed at a ratio 1:(0.8-1.2) with the solution, containing 250-300 g/dm3 chlorides of alkali metals, and is heated to 85±5°C. With the use of solution of sodium hydroxide as the alkaline reagent treatment of the suspension is performed to pH 2.0+0.5, then this solution is held for 0.5+0.1 hr, then solution of high molecular flocculant- hydrolysed oilacrilamid - is introduced and is held without mixing for 2.0±0.5 hrs. After that the thickened part of the suspension is fed to a nutsch-filter, the produced sediment - rare metal concentrate - is dried, tempered and transfered to chlorination of source loparit concentrates. Filtrate is combined with clarified portion of the suspension, heated to 80±10°C and treated with solution of sodium hydroxide to pH 12.0±0.5. Produced oxihydrate pulp is held at 80±10°C for 1.0±0.5 hrs and is fed to a filter-press-I; the extracted radioactive sediment is washed out at the filter-press-I 3-4 volumes of water, and process water is merged with shop flush water. The washed out sediment is blown out with a compressed air at the filter-press-I, then unloaded and transported to SWS, while mother solution is mixed at a ratio of 1:(10-20) with iron containing shop flush water. Produced radioactive chloride solution is heated to 80±10°C and treated with solution of sodium hydroxide to pH 12.0±0.5, the resulted pulp is held at 80±10°C and pumped to a filter-press-II with production of deactivating solution, which is discharged to a shop drainage, and with production of sediment; the latter is merged with the sediment - rare metal concentrate, extracted out of suspension after dissolving of the spent melt SSF; the said sediment is heat treated and partially neutralized, then dried, tempered and transferred to chlorinating in saline chlorinators together with the source loparit concentrate.

EFFECT: upgraded degree of deactivation of solutions and discharge waters and additional extraction of valuable elements.

2 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to method of regenerative purification of copper-ammonia etching solutions. Method includes neutralisation of solutions with acidic agent, sedimentation of copper in the form of hard-soluble compound and separation of sediment from solution. Neutralisation involves using as acidic agent of hydrochloric acid solution or acidic solutions of copper plating to minimal values of content of residual copper in solution. Separated hard-soluble copper compound is regenerated by dissolving, obtaining copper chloride concentrate. After sediment separation, water is removed from solution and, in presence of organic solvent, ammonia chloride is isolated for preparation of galvanic solutions of copper plating. Organic solvent is regenerated by distillation, and residual copper is removed from solution during acidification by iron cementation.

EFFECT: regeneration of ammonia chloride and copper cations from solutions, their use in processes of galvanic solution preparation and purification of sewage water with content of copper cations lower than MPC values.

2 ex

FIELD: metallurgy industry.

SUBSTANCE: as per the first version, the method involves activation of fine carbon base with laminate-type structure by being intercalated in water solutions of strong acids and further interaction of intercalated base with hexachloroplatinum acid by introducing it, reduction of interacting products till platinum is obtained and oxidation of carbon base. As per the second version, the method involves interaction of fine carbon base with hexachloroplatinum acid in the presence of chloride, reduction of interacting products till platinum is obtained and oxidation of carbon base.

EFFECT: simplifying manufacture and increasing economy of the process.

2 cl, 1 dwg, 3 ex

FIELD: metallurgy industry.

SUBSTANCE: as per the first version, the method involves activation of fine carbon base with laminate-type structure by being intercalated in water solutions of strong acids and further interaction of intercalated base with hexachloroplatinum acid by introducing it, reduction of interacting products till platinum is obtained and oxidation of carbon base. As per the second version, the method involves interaction of fine carbon base with hexachloroplatinum acid in the presence of chloride, reduction of interacting products till platinum is obtained and oxidation of carbon base.

EFFECT: simplifying manufacture and increasing economy of the process.

2 cl, 1 dwg, 3 ex

FIELD: metallurgy.

SUBSTANCE: method consists in processing solution with sodium nitrite at heating, in pulp cooling and in separating sediment of base metals. Before sodium nitrite treatment solution is neutralised with alkali to contents of HCI 50-70 g/l; produced sediment containing antimony is filtered. Further redox potential of solution is reduced with iron powder to 500-550 mV for extracting gold into cementite. Sediment containing antimony is dissolved in hydrochloric acid. Produced solution is filtered and treated with oxidiser to redox potential 800-1000 mV for purification from suspension. Further solution is diluted with water to contents of HCI 80-100 g/l, and produced antimony sediment is separated and washed with water.

EFFECT: antimony and gold are extracted into separate products with low contents of platinum metals in main part of processing hydrochloric acid solutions containing noble and non-ferrous metals; consumption of sodium nitrite is reduced at solution nitration.

2 ex

FIELD: metallurgy.

SUBSTANCE: method consists in leaching of source product in solution of caustic soda, in separation of non soluble residue from alkali solution, and in melting of non soluble residue with additives. After melting melt is settled and cooled to solidification, then hardened metal is divided along borders of phase division to slag and bottom heavy melt. Further, bottom heavy melt is crumbled into powder and processed as concentrate of refinery production, then leached in solution of hydrochloric acid wherein gaseous chlorine is supplied. Additives not containing selenium, tellurium or their compounds are used at melting of non soluble residue. Upon crumbling bottom heavy melt produced at melting is treated with solution of nitric acid; nitric acid solution containing lead and silver is separated from non soluble residue processed as concentrate of refineries.

EFFECT: additional extraction of lead from source product.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: method consists in diluting material with water and in treating pulp with nitric acid. Further, not dissolved material is separated, washed and chlorinated in hydrochloric acid and pulp is filtrated. Upon filtration hydrochloric acid solution is neutralised; sediment of impurities of non-ferrous metals is separated from solution containing noble metals. Also upon diluting pulp is treated with nitric acid to redox potential of 800-900 mV. Sodium chloride is introduced into obtained hydrochloric acid solution first, then formed silver salt is separated, solution is treated with sodium sulphate and lead salt is filtered off. Further, redox potential of solution is reduced to 300-450 mV by introducing light alloy containing copper for reduction of palladium and its precipitation. Then sediment is separated, and solution is neutralised with alkali; formed sediment containing copper is filtered.

EFFECT: upgraded degree of separation of non-ferrous and noble metals and extracting of silver, copper, and lead into selective product with low contents of platinum metals.

1 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in refining platinum-group metals. A residue consisting of a mixture of hydrated oxides of osmium and ruthenium is saturated with water. The obtained pulp is treated with hydrochloric acid and oxidising agent until dissolution of the residue while heating. The oxidising agent used is hydrogen peroxide or sodium chlorate. Osmium oxide is removed by sucking through an air system. The solution remaining after removal of osmium is filtered, treated with concentrated hydrochloric acid and heated for 2 hours. Ammonium chloride is added and ammonium chlororuthenate is precipitated. The obtained salt is washed from the mother solution.

EFFECT: selective extraction of osmium and ruthenium, shorter duration of the process and reduced consumption of reagents.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: device for extraction of noble metals from solutions by cement injection contains tank and container, filled with metal-cement injector. Tank is outfitted by jacket heating and is implemented with conical end, hatch of reactants loading, branches of discharge and filling in of solutions and sealed cover. Container with metal-cement injector is located on sealed cover of tank and allows horizontal branch of feeding of solution into container. It also allows vertical branch, bottom end of which is deepened into tank for abstraction of solution from tank by means of screw electric pump. Bottom of container allows punching with diametre of openings 2.5-3 mm. Tank is implemented from titanium.

EFFECT: efficiency and operating safety of the device.

3 cl, 1 dwg, 2 ex

FIELD: metallurgy.

SUBSTANCE: disclosed method consists in oxidizing autoclave leaching at 160-200C temperature in sulphuric acid medium under oxygen pressure, in neutralisation of excessive acid with neutralising agent; in hydro-thermal treatment of neutralised pulp in autoclave at 160-200C temperature, in separation of sediment from solution and in forming rich copper concentrate containing noble metals and zinc solution. Also excessive acid is neutralised from liquid phase of pulp of oxidizing autoclave leaching preliminary separated from solid phase; and waste gypsum cake is separated. Solution separated from cake is mixed with solid phase of pulp of oxidising autoclave leaching; neutralised pulp is produced. This pulp is directed to hydro-thermal treatment.

EFFECT: increased extraction of noble metals, reduced time of treatment.

2 cl, 1 tbl

FIELD: metallurgy.

SUBSTANCE: invention relates to analytical chemistry of noble metals (NM), namely to assaying and can be used for indentification of gold and platinum metals (PM) in the sulfide ores and their processing products. The method involves preparation of a mixture from a batch of a sample of the analysed material with sodium nitrate or potassium nitrate, lead monoxide, sodium carbonate, silicate glass, sodium tetraborate, calcium oxide, silver nitrate or silver chloride and carbonaceous reducer. The prepared mixture is heat treated at a temperature of 400-600C for 20-30 min. This is followed by melting of the mixture at 1100-1300C obtaining slag and lead alloy - lead bullion. After melting the heat products are cooled and separated. After separation the lead bullion is cupeled to obtain a silver or gold-silver globule and identify the content of noble metals in the globule using chemical and physical-chemical methods.

EFFECT: reduced costs because of reduced duratio of the analysis.

2 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the method for selective extraction of gold from aqueous thiocyanate solutions. The method involves sorption on an anionite with subsequent desorption of gold from the anionite. Extraction is done from solutions containing gold in form of a stable complex of Au (I) and metal impurities iron (III), copper (II), zinc (II), silver (I), cobalt (II), and nickel (II). Sorption is done on an AN-251 anionite. Before desorption of gold, the anionite is treated with a 0.005-0.05 M H2SO4 solution in static conditions for desorption and removal metal impurities. Desorption of gold from the anionite is done using a 1-5 M KSCN solution in the presence of 2-10% KOH. The method is environmentally safe.

EFFECT: faster and selective extraction of gold, as well as possibility of complete separation of gold from iron, copper, zinc, nickel, cobalt and silver ions.

2 tbl, 4 ex

FIELD: noble metal hydrometallurgy.

SUBSTANCE: invention relates to method for acid leaching of platinum method from secondary raw materials, in particular from ceramic support coated with platinum metal film. Target metals are leached with mixture of hydrochloric acid and alkali hypochlorite at mass ratio of OCl-/HCL = 0.22-0.25 and redox potential of 1350-1420 mV.

EFFECT: decreased leaching temperature, reduced cost, improved platinum metal yield.

2 ex

Up!