Leaching of complex gold ore using a cyanide-glycine solution

In this research, the leaching of complex gold ore was studied using cyanide and glycine. In the absence of glycine, the gold dissolution increases from 6.47 to 62.21% with increasing the cyanide concentration from 250 to 4500 g/t. The ore contains sulfide minerals and base metals, such as copper, zinc, and silver, which are high cyanide consumers. At 2000 g/t cyanide concentration, the gold dissolution significantly increases from 30 to 92% with adding 0.5 mol/L of glycine. A further increase in the glycine concentration has no significant effect on the dissolution of gold. At 2000 g/t cyanide and 0.5 mol/L glycine concentrations in the absence of H2O2, the dissolution of gold is 78%, which increases to 88% and 93% with increasing the H2O2 concentration to 1 and 1.5%, respectively. The solid content is very effective in the range of 20-25%. Further increases in the solid content to 30, 35, and 40% do not have a significant effect on the gold dissolution. When only glycine is in the system, the gold dissolution is very low, and when only cyanide is in the system, the gold and copper dissolutions are almost the same. The solubility of copper in the presence of cyanide and glycine is the same, but the solubility of gold in cyanide is much higher than glycine.