SILVER AND PALLADIUM RECYCLING FROM THE SECONDARY RESOURCES
Abstract
Elektrochemical and chemical technology for the treatment of the separated electrotechnic scrap with silver and palladium content in laboratory scale were tested and verified. Separated electrotechnic Ag-Pd scrap is mainly represented by various types contacts from the electric and electronic devices and apparatures. As a basic material of the body of these contacts is most frequently used copper alloys for example different types of bronzes or brasses. Contact layer is presented by galvanically coated silver surface or silver-palladium alloy surface. Silver and palladium content in such separated contacts is 5 - 23 % Ag and 2,5 - 8,5 % Pd according to the grade of separation.
There steps electrochemical and chemical methode of the treatment of separated electric contacts is suggested, described and werified in this paper. The first step is based on copper electrolysis, the second step is based on silver electrolysis and the third step is presented by selective chemical Pd precipitation.
There were verified, that is possible to obtain in the first step by Cu electrolysis metallic copper with the 96,06 % purity and 76 % efficiency. In the second step is possible by Ag electrolysis to obtain metallic silver with the purity 99,95 % Ag and 82 % efficiency. In third step is possible by chemical precipitation to obtain palladium-sponge with the purity 99,75 % Pd and 95 % efficiency. In the case of low Pd content solutions recycling is possible to raise the efficiency of palladium extraction.
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