Separation of Gold from Sulfide Using a Plasma Arc Fuming Process

Transferred-arc plasma treatment of iron sulfides containing gold is examined from both thermodynamic and experimental points of view. Three cases are analyzed: argon plasma with sulfide, argon plasma with a carbon–sulfide mixture, and argon–methane plasma with sulfide. The carboreduction of the materials appears to be well adapted for gold separation by fuming, but experimentally the process is limited by the poor mixing of graphite with molten material. The reduction with a CH₄ (10%) plasma is a proved alternative to the aforementioned process. A gold extraction efficiency of 90% is achieved for batch smelting operations.