Lélectrométallurgie

L'électrométallurgie refers to the branch of metallurgy that uses electrical energy in the extraction and refining of metals. This process involves using electric furnaces or electrolytic cells to achieve high temperatures or to drive chemical reactions that separate metals from their ores or impurities. There are two main categories within electrometallurgy: electrothermal processes and electrolytic processes.

Electrothermal processes utilize electrical energy primarily for heating. Electric arc furnaces and induction furnaces are examples of equipment used in this method. These furnaces can reach the very high temperatures required to melt and reduce metallic oxides, such as in the production of aluminum from alumina, or for producing ferroalloys. The heat generated by electrical resistance or arcs is crucial for overcoming the high melting points and chemical stability of certain metal compounds.

Electrolytic processes, on the other hand, use electrical energy to drive a non-spontaneous chemical reaction, typically the decomposition of a molten salt or an aqueous solution. Electrorefining, a common application, uses electrolysis to purify metals like copper and nickel. In this process, impure metal is used as the anode, and a pure metal cathode is used. When an electric current passes through an electrolyte, the impure metal dissolves, and pure metal deposits onto the cathode, leaving impurities behind. Electrowinning, another electrolytic method, extracts metals directly from solutions of their salts, producing pure metal at the cathode.