HYDROMETALLURGICAL METHOD FOR SEPARATING GOLD, SILVER, PLATINUM, AND PALLADIUM FROM MATERIAL CONTAINING THEREOF WITH SIMULTANEOUS ENRICHMENT OF METALS Russian patent published in 1997 - IPC

FIELD: hydrometallurgical separation of precious metals. SUBSTANCE: initial material is melted and granulated and granules are dissolved in nitric acid solution. Non-dissolved solids are precipitated in the form of hydroxides, filtered off, and caked. Cake is further dissolved in aqua regia and excess oxidant is removed with urea or soda ash. Resultant solution is filtered and submitted to gold precipitation, while from gold-free solution, platinum and palladium are precipitated. Silver-containing solution is electrolytically treated to separate silver in the form of its chloride followed by melting it into ingots. EFFECT: enhanced efficiency of process and increased purity of isolated metals. 3 cl