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INVENTION
Patent of the Russian Federation RU2171301
METHOD OF EXTRACTING PRECIOUS METALS, IN PARTICULARITY OF SILVER, FROM WASTE
The name of the inventor: Loleit SI; Kalmykov Yu.M .; Davydov V.Ya.; Agafonov OV; Ilchenko G.A.
The name of the patent holder: Shchelkovo Plant of Secondary Precious Metals
Address for correspondence: 141551, Moscow region., Solnechnogorsk district, Kryukovo, AOOT "NPO Stekloplastik," to the director of SCHZVDM S.Lolaytu
Date of commencement of the patent: 1999.06.03
The invention relates to metallurgy and can be used in the extraction of precious metals, in particular silver, from recycled materials, namely from electronic waste.
The technical result of the invention is to maximize the recovery of silver and other precious materials, which is achieved by the fact that in the method for recovering precious metals, in particular silver, including melting waste in the presence of a flux containing soda, borax and sodium nitrate, according to the invention, the raw material before melting Are crushed and grinded, followed by sifting the ground material first through a screen 12 , then through a screen 45, melting the sieved material is carried out at a temperature of 1000 to 1190 ° C. while maintaining a 2: 1: 1 ratio of sodium, boric and sodium nitrate.
DESCRIPTION OF THE INVENTION
The invention relates to metallurgy and can be used in the recovery of precious metals from recycled materials, namely from electronic waste.
A method for the production of silver from silver chloride is known (German Patent No. 3827605 Class C 22 B 3/00 is an analogue) comprising treating an aqueous suspension of silver chloride with glucose and a caustic soda, and then silver is recovered by reaction with glucose.
The disadvantage of the known method is the high consumption of an expensive reagent-glucose, low purity and its minimum amount.
The method of extracting precious metals, in particular silver ( Meretukov MA et al., Metallurgy of Noble Metals, Foreign Experience, M .: Metallurgy, 1991, pp. 324 - prototype), which includes melting, is the closest to the technical essence and the result achieved Waste in the presence of flux containing soda, borax and sodium nitrate.
The drawbacks of the known method are large losses of silver with slags and the fact that most of the waste containing silver chloride does not melt together with the filler material, forming a non-melted formless mass.
The technical result of the invention is the maximum extraction of silver and other precious metals.
The technical result is achieved by the fact that in the method for recovering precious metals, in particular silver, including melting waste in the presence of a flux containing soda, borax and sodium nitrate, according to the invention, the raw material is crushed and milled, followed by sifting the crushed material, first through an N 12 , then through a No. 45 mesh sieve, melting of the sieved material is carried out at a temperature of 1000 to 1190 ° C. , while maintaining a 2: 1: 1 ratio of sodium, boric and sodium nitrate, the alloy obtained after melting is sent for refining.
Example 1
The starting product containing silver chloride and the minimum content of gold, platinum and palladium is sent first to crushing in screw crushers, and then to grinding. The resulting material is screened through a No. 12 sieve , followed by a No. 45 mesh screen. To the obtained ground material, a mixture of fluxing agents in a ratio of 2: 1: 1 is added, namely a mixture consisting of the following components, parts by weight.
:
Calcined soda - 100 - 200
Bura - 50 - 100
Sodium nitrate - 50 - 100
With further mixing of the ground material and a mixture of fluxing agents.
The resulting material is placed in a crucible and sent to an induction furnace to melt the material at a temperature of 1000 ° C.
The melt is then poured into molds, cooled to room temperature, the slag is separated from the metal and the resulting silver alloy is sent to the refining.
Example 2
The procedure is the same as in Example 1 , but melting of the sieved material in the presence of fluxing agents in an induction furnace is carried out at a temperature of 1190 ° C.
CLAIM
A method for recovering precious metals, in particular silver, comprising melting the waste in the presence of a flux containing soda, borax and sodium nitrate, characterized in that the raw material is crushed and milled prior to melting, followed by screening of the crushed material, first through a sieve 12 , then through a sieve 45 , Melting of the sieved material is carried out at a temperature of 1000-1190 ° C , while maintaining the ratio of sodium borate, sodium borax and sodium nitrate in 2: 1: 1, and the alloy obtained after melting is sent to refining.
print version
Date of publication 07.11.2006гг
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