Electrometallurgy

Abstract

Electrometallurgy is an important branch of metallurgy which uses electrical energy in winning of metals from leach liquors and refining of crude metals obtained via the pyrometallurgical route (e.g., blister copper and lead bullion) as well as by hydrometallurgical and electrometallurgical routes (e.g., aluminum). This branch of metallurgy also includes the extraction of metals and alloys by electrothermic smelting. In this chapter, discussion is confined to electrowinning and electrorefining. Before discussing the principle of electrometallurgy, it would be interesting to note the difference between electrowinning and electrorefining. Electrowinning is an electrolytic extraction method in which cathodic reduction is made use of to deposit the desired metal from the electrolyte that is obtained from a leaching step in the flow sheet. The process uses insoluble or inert anodes and the anodic process supports a gaseous evolution reaction. Contrary to this, electrorefining uses anodes of impure metal to be refined and the cathode is of pure metal starting sheet or a blank of another metal. In electrorefining, the anodic reaction is a metal dissolution reaction, which is reverse of the cathodic reduction. In electrowinning, the anodic reaction is usually oxygen evolution from aqueous solutions: © 2021, The Minerals, Metals & Materials Society.