Lhydrométallurgie

Lhydrométallurgie is a branch of metallurgy that uses aqueous chemistry to recover and refine metals from their ores or recycled materials. It involves the use of water-based solutions to selectively dissolve target metals, followed by processes to separate and purify them. This contrasts with pyrometallurgy, which employs high temperatures.

The hydrometallurgical process typically begins with leaching, where the ore or material is treated with a chemical solution, often acidic or alkaline, to solubilize the desired metal. Common leaching agents include sulfuric acid, cyanide, or ammonia, depending on the metal and ore composition. After leaching, the resulting pregnant leach solution, containing the dissolved metal, undergoes purification. This can involve techniques like solvent extraction, ion exchange, or precipitation to remove impurities and concentrate the metal.

Finally, the purified metal is recovered from the solution. Electrodeposition, where an electric current is used to plate the metal onto a cathode, is a widely used method. Alternatively, chemical reduction or cementation can be employed. Hydrometallurgy is often favored for its ability to process low-grade ores, its environmental advantages over some pyrometallurgical methods, and its suitability for recovering precious and base metals like copper, gold, nickel, and zinc.