| Start of section
Production, amateur Radio amateurs Aircraft model, rocket-model Useful, entertaining |
Stealth Master
Electronics Physics Technologies Inventions |
Secrets of the cosmos
Secrets of the Earth Secrets of the Ocean Tricks Map of section |
  |
| Use of the site materials is allowed subject to the link (for websites - hyperlinks) | |||
Navigation: => |
Home / Patent catalog / Catalog section / Back / |
|
INVENTION
Patent of the Russian Federation RU2096506
METHOD OF EXTRACTION OF SILVER FROM MATERIALS CONTAINING SILVER SILVER, ADDITIONS OF GOLD AND METALS OF THE PLATINUM GROUP
The name of the inventor: Loleit SI; Kalmykov Yu.M .; Ilchenko GA; Lebedev VA; Ilchenko EA; Nikitin V.P.
The name of the patent holder: Shchelkovo Plant of Secondary Precious Metals
Address for correspondence:
Date of commencement of the patent: 1996.07.05
Usage: refers to the method of silver recovery from materials containing silver chloride, gold and platinum group metals, in particular from recycled materials. SUMMARY OF THE INVENTION: the smelting of the feedstock is carried out in the presence of fluxes forming an alkali metal oxide, blowing the melt with dry air at a temperature of 1100-1150 ° C., followed by granulation. Then, dissolution of the granules, separation of the insoluble gold-containing residue, hydrolysis of the solution containing silver nitrate, production of a pulp having a precipitate of predominantly metal impurities, precipitation of silver by electrolysis, dissolution of the hydroxide precipitate, precipitation of the concentrate of platinum metals, and production of refined silver are carried out.
DESCRIPTION OF THE INVENTION
The invention relates to metallurgy and can be used in the recovery of precious metals from recycled materials.
A method is known for the production of silver from silver chloride [1], which comprises treating the aqueous suspension with glucose and caustic brew, and sodium hydroxide is added to the aqueous suspension of the chloride, and then silver is recovered by reaction with glucose. The reaction temperature is maintained at 95 ° C.
A disadvantage of the known method is the high consumption of an expensive glucose reagent, low purity and a minimum amount of the final product.
The most similar in technical essence and achieved result is the method of silver recovery from wastes containing silver chloride [2-prototype] including melting of waste in the presence of a fluxing agent, in particular borax and carbon, preferably at a temperature of 1200-1400 ° C. In this case, Under a layer of slag. Then a silver fraction is separated from said melt, the waste containing silver chloride melting together with a filler material which forms an alkali metal oxide without releasing the gas in a significant volume.
The disadvantage of the known method is the large loss of silver with the slag and the low purity of the silver-containing alloy.
The technical result of the invention is the maximum extraction of silver into finished products and other precious metals into concentrates by increasing the purity of the final product.
The technical result is achieved by the fact that a method for recovering silver from materials containing silver chloride, gold impurities and platinum group metals, which includes smelting the starting material in the presence of fluxes forming an alkali metal oxide, separating the resulting rough silver from the slag, characterized in that the draft silver Melting when a layer of calcined soda is charged to the surface of the melt and when the melt is blown dry air at a temperature of 1100-1150 ° C followed by granulation, then the granules are dissolved in a solution of nitric acid, the insoluble gold-containing residue is separated by filtration, and the solution containing mainly silver nitrate, Are subjected to hydrolysis in the presence of sodium hydroxide to obtain a pulp containing a precipitate of predominantly hydroxides of metal impurities, including platinum metals, pulp filtration is carried out, silver is precipitated from the resulting solution, electrolysis, and the hydroxide precipitate is dissolved in a minimum amount of nitric acid solution, Is treated with sodium thiosulfate to precipitate the concentrate of platinum metals, the filtration is carried out and the resulting solution is combined with the solution after hydrolysis and subjected to electrolysis to obtain refined silver, with soda ash and / or lime and / or dolomite flour and / or sodium nitrate , And to reduce the consumption of sodium hydroxide before hydrolytic purification of the silver solution from impurities, distillation of nitric acid by partial evaporation is carried out.
Examples of the method.
Example 1 . The material containing Ag, silver chloride Pt, Pd, Se, Te, a, and Bi, Sn is batch with soda ash in a ratio of 1: 0.7, loaded in 20-25 kg portions into the melting crucible of the induction furnace, heated and melted. After complete melting, the contents of the crucible are poured into an inclined mold and allow the melt to freeze. After solidification of the metal and slag, the mold is knocked out and metal silver is separated from the slag. The obtained ingots with a total mass of the order of 200 kg are melted, then calcined soda is loaded onto the surface of the melt to form a layer of 2-3 cm, the melt is heated to a temperature of 1100 ° C and the melt is started to blow through the dry air. Purge is carried out for 30 minutes, after which the main mass of slag containing selenium and tellurium is drained, the slag residues are thickened by the addition of sand and the thick silicate slag is removed manually. The molten metal is poured into water through a perforated funnel, the granules are separated from water and dissolved in nitric acid until the solution is saturated with silver and the acid is almost completely deactivated. The resulting solution in an amount of about 800 kg is filtered from the insoluble gold-containing residue, pumped into a stirred reactor and slowly added to a 10% solution of alkali until a pH of 6. When the pH of the solution has reached this value, add 5% NaOH solution in an amount of 5% Of the volume of the solution, kept with stirring for 30 minutes and the resulting pulp is drained onto a vacuum filter. The hydroxide precipitate is washed with a small amount of water and dissolved in a small amount of HNO 3 diluted 1: 1. The resulting solution is pumped into a stirred reactor and slowly a 0.5% solution of sodium thiosulfate is poured in for 40 minutes. After all thiosulfate has been added, the solution is stirred for 1 hour and the sulphide precipitate is filtered off, and the solution is combined with the solution obtained after filtering the hydroxides and subjected to electrolysis.
As a result of the proposed operations, the following products are obtained:
- Affined silver with a purity of 99.99%
- Slag with a silver content of 0.24%
- Platinum-palladium concentrate with Pt content, Pd 12.26%
Example 2 . Carry out in a manner similar to Example 1, but the draft silver obtained after melting the waste with a fluxing agent is melted into pellets while blowing dry air at a temperature of 1150 ° C. for 40 minutes.
CLAIM
1. A method for recovering silver from materials containing silver chloride, gold impurities and platinum group metals, comprising: smelting the starting material in the presence of fluxes forming an alkali metal oxide, separating the resulting rough silver from the slag, characterized in that the silverware is melted during loading on The melt surface of the soda ash layer and the melt blowing with dry air at 1100 to 1150 ° C, followed by granulation, then dissolving the granules in a solution of nitric acid, separating the insoluble gold-containing residue by filtration, and the solution containing mainly silver nitrate is hydrolyzed in the presence of hydroxide Sodium hydroxide solution is precipitated from the resulting solution by electrolysis, and the hydroxide precipitate is dissolved in a minimum amount of nitric acid solution, the resulting solution is treated with sodium thiosulfate to precipitate a concentrate of platinum Metals, filtration is carried out and the resulting solution is combined with the solution after hydrolysis and subjected to electrolysis to obtain refined silver.
2. The method of claim 1, wherein the flux is soda ash and / or lime and / or dolomite flour and / or sodium nitrate.
3. The method of claim 1, wherein in order to reduce the consumption of sodium hydroxide before hydrolytic purification of the silver solution from impurities, nitric acid is distilled off by partial evaporation.
print version
Date of publication 14.03.2007gg
Comments
When commenting on, remember that the content and tone of your message can hurt the feelings of real people, show respect and tolerance to your interlocutors even if you do not share their opinion, your behavior in the conditions of freedom of expression and anonymity provided by the Internet, changes Not only virtual, but also the real world. All comments are hidden from the index, spam is controlled.