ECOLOGICALLY CLEAN METHOD OF UNDERGROUND LIXIVIATION OF NOBLE METALS Russian patent published in 1997 - IPC

FIELD: non-cyanide technology of lixiviation of noble metals, preferably cold and silver from ores at place of their occurrence. SUBSTANCE: method implies successive pumping of reagent solutions into stratum through a system of pumping bore-holes and pumping-out of productive solutions with subsequent processing of productive solution. Lixiviation is performed in two stages. Used in first stage is chlorine solution, and its delivery into stratum is regulated so that pH of pumped-out solution is maintained above 3. Prior to processing productive solution, chlorine surplus is restored in it. In second stage, simultaneously performed are treatment of stratum and its deactivation by pumping-in of sodium thiosulphane up to obtaining of pumped-out solution having pH of stratum water of ore holding level, also performed is processing of productive solution. EFFECT: high efficiency. 6 cl, 1 tbl