ACID OXIDATION OF REFRACTORY GOLD CONCENTRATE BEFORE CONVENTIONAL GOLD RECOVERY

摘要

In the recovery of gold from refractory auriferous iron containing concentrates, e.g. by cyanidation, gold recovery is improved by pretreating the concentrate as an aqueous slurry with aqueous sulphuric acid solution (18) to decompose carbonate and other acidic consuming gangue compounds. The treated slurry is then oxidized in a pressure oxidation step (20). Water is then added to the oxidized slurry in repulping steps (22, 26) to produce a repulped oxidized slurry which is then subjected to a liquid-solids separation step (28) to produce an acid and iron containing solution, a portion of which is recycled to the acidic pretreatment step (18), and oxidized separated solids from which the gold can be recovered in improved yield by further conventional, e.g. cyanidation, processing.