Isolation of Precious Metals Contained in a Gold and Silver Alloy
A. B. LEBED, D. YU. SKOPIN and G. I. MALTSEV
Electromed’ JSC, Ul. Lenina 1, Verkhnyaya Pyshma 624021 (Russia)
mgi@elem.ru
Keywords: gold, silver, platinum, palladium, nitric acid, ammonium nitrate, nitric oxide, molecular nitrogen, chemical reaction, stoichiometric factor, electrochemical extraction, refining
Pages: 127–134
Abstract
Studies were performed concerning the process of obtaining noble metals (gold, silver, platinum, palladium) and tellurium, involving the following process stages: dissolving the gold and silver alloy in nitric acid solutions in the presence of ammonium nitrate under the gas phase pressure; purifying the leaching solutions via sorption (from platinum and palladium) and via hydrolytic precipitation (from copper and tellurium); electrochemical extraction of silver-containing solutions to produce cathode silver; conditioning and refining the gold sludge; an electrochemical extraction of eluates containing platinum group metals; obtaining tellurium concentrate. The number and type of linearly independent reactions have been found out for the dissolution of the parent alloy, key components for the stoichiometric description of chemical reactions in the system have been identified. A mathematical evaluation of quantitative changes in the complicated heterogeneous system with polyvalent nitrogen is presented.
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