METHOD FOR EXTRACTING GOLD FROM CONCENTRATES Russian patent published in 2012 - IPC C22B11/02 C25C1/20 

FIELD: metallurgy.

SUBSTANCE: concentrate is mixed with lead-containing materials, reducing agent and slag-forming fluxes. Concentrate melting is performed at temperature of 1100-1200°C so that gold-lead alloy is obtained. The formed gold-lead alloy is subject to electrolytic dissolution in nitric-acid electrolyte at anodic current density of 800-1500 A/m² and continuous supply to electrolysis bath of fresh electrolyte containing 15-30 g/l HNO₃ with the flow rate at which merchantable electrolyte leaving the bath includes 1-3 g/l HNO₃ and 50-100 g/l Pb(NO₃)₂. At that, in order to prevent the lead reduction, cathode is separated from anode of anion exchange membrane. Gold is extracted to sludge, and lead is deposited from electrolyte in the form of hardly soluble salt that is returned to melting.

EFFECT: increasing gold extraction degree.

3 cl, 2 tbl