ALTA 2016: The use of special additives to inhibit preg-robbing of gold in the process of double refractory concentrates pressure oxidation.

In Proceedings of ALTA 2016 Gold-PM Session, 2016
oFomenko, I. V, Pleshkov, M. A., Zaytsev, P. V, Chugaev, L. V, Shneerson, Y. M.

Pressure oxidation is one of the most common and reliable methods of processing gold sulfide concentrates. It allows effective sulfides decomposition, thus eliminating the primary cause of material’s refractoriness to gold cyanide leaching. Nevertheless, the pressure oxidation of double refractory materials containing carbonaceous matter in addition to sulfides results in substantial gold losses due to the autoclave preg-robbing. The latter involves sorption of soluble gold compounds by the carbonaceous matter under the POX conditions.

Chloride ion is a common component of POX solutions. It is capable of forming soluble complexes with gold when presenting in the solution even in an amount of 1–10 mg/l.

The present research aims to study the effect of special additives capable of reacting with chloride ion or carbonaceous matter components, thereby minimizing their negative impact on gold recovery in the process of POX residue cyanide leaching. The salts of silver, bismuth, lead and mercury are among the studied additives.