METHOD OF EXTRACTING GOLD AND SILVER FROM ACTIVE COALS Russian patent published in 2020 - IPC C22B11/00 C22B3/24 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy of precious metals and are intended for extraction of gold and silver from active coals. Processing of active coal saturated in cyanic solutions involves electro-elution of noble metals with thiocarbamide-alkali-cyanide solutions at temperature of 80–100 °C and atmospheric pressure in closed cycle. Electro-elution is carried out in two stages: at the first stage, silver is electro-eluted with solutions of sodium hydroxide and sodium cyanide at concentration of 0.5–10 g/l, at the second stage thiocarbamide is added to circulating solutions and gold is electro-eluted, wherein the concentration of thiocarbamide, hydroxide and sodium cyanide is maintained at 0.5–10 g/l of each. When using coal, which is silver-poor, with weight ratio Ag:Au less than 2, gold electrohelching is carried out at concentration of thiocarbamide, sodium hydroxide and sodium cyanide of 0.5–10 g/l of each.

EFFECT: invention increases efficiency of electroelution of silver-gold-bearing coal, reduces duration of the process while reducing consumption of reagents.

6 cl, 2 tbl, 2 ex