Complex processing technology of gold-bearing concentrates: Autoclave leaching with subsequent roasting

The object of investigation is an autoclave cake of the refractory gold-containing flotation concentrate prepared using a pilot plant. The influence of heat treatment (HT) on the chemical composition and recovery of gold is investigated for this material in a temperature range of 100–500°C. Due to the HT, it is possible to acquire high recovery of gold up to 98%. This is attained due to deep removal during the HT of organic carbon, which passivated gold during the autoclave oxidation. Arsenic is situated in a stable nontoxic form of iron arsenate, which undergoes no variations in the content and remains in the cake at the HT stage throughout the temperature range under study. The possibility in principle to process the double refractory concentrate with the help of a complex technology of autoclave oxidation and subsequent HT is shown.