Slimes treatment process

Abstract

Slimes from electrolytic copper refinery are first treated by leaching them with dilute sulphuric acid under an oxygen partial pressure of up to 50 psi and an elevated temperature, until copper and tellurium present in the slimes are substantially dissolved, and effecting a liquid-solid separation of the leached slurry so produced to separate the leach liquor from the leach slimes. The leach liquor is then treated with metallic copper to cement the tellurium as copper telluride. The latter is separated from the remaining solution which is suitable for the production of copper sulphate. The leach slimes containing mainly selenium, lead, silver, gold and other impurities are dried, mixed with a binder and pelletized and the pellets are then roasted to remove selenium as selenium dioxide. Finally, the roasted pellets are smelted to remove the remaining impurities leaving a dore metal containing essentially silver and gold.

Dependencies are inferred from the claim text.