Electrochemical Recovery of Gold

Significance

• Sulfide ore, or sulfur-based ore, is generally semi-conducting. In other words, its responsive to electricity. This trait facilitates electrochemical reactions that support separating, recovering and purifying the ore̵7;s gold content. Approximately one third of all gold production is the byproduct of using electrochemical extraction methods while processing metals such as copper, zinc and lead.

The Facts

• Certain types of gold respond favorably to electrochemical flotation, a process involving the crushing of ore as a means of liberating its gold content. Introducing chemical compounds with powerful bonding properties causes the ore̵7;s content to ̶0;float̶1; and separate a target metal from within crushed sulfide ore.

Flotation

• Electrochemical recovery of gold happens in flotation cells containing water. After flotation occurs, the electrochemical process continues when a technician injects air bubbles into the cell. The process circulates gold through multiple banks of water-filled cells. Further electrochemical refining occurs after the heavy gold particles separate from the ore̵7;s lighter minerals.

Electrowinning

• Solutions containing metal may also undergo electrowinning, which is an extractive process that recovers metals through electrolysis. Placing a positive and negative electrode into the solution causes the passing of an electrical current between the two electrodes. The result is the formation of a recoverable metal deposit on the negative electrode.

Electrorefining

• An electrochemical process known as electrorefining produces purified metal from impure metal, according to the Case Western Reserve University Electrochemistry Dictionary. An electrical current forces a reaction that makes chemical energy; the result is pure metal depositing onto an electrode. Other names for this process are ̶0;electrolytic refining̶1; and ̶0;metal refining.̶1;