Hypochlorite Pretreatment of a Low Grade Carbonaceous Gold Ore,Role of Oxygen in the Pretreatment Process

Hypochlorite pretreatment of a refractory carbonaceous gold ore showed promise as a method for oxidizing sulfidic and carbonaceous materials prior to conventional cyanide heap leaching. However, previous studies showed hypochlorite consumption is high and gold extraction is proportional to hypochlorite consumption. The high hypochlorite consumption is due to oxygen depletion as the solution percolates through the ore charge. The relation of dissolved oxygen, potential, and pH with the bed height are investigated. The effect of solution application into the ore charge at different elevations on reagent consumption will be discussed.