Hydrometallurgy is a metallurgical process carried out in solution. In the hydrometallurgical process, the temperature can reach about 200 ℃ in general, but it is not lower than the temperature of 100 ℃ in some cases

Hydrometallurgy includes leaching, purification and metal preparation.

Leaching the treatment of ore or concentrate with a suitable solvent so that the metal to be extracted enters the solution in the form of some ion (cation or complex anion), while gangue and other impurities do not dissolve. This process is called leaching. After leaching, the leach liquor containing metal (ion) and insoluble residue (leaching residue) made of gangue mineral silk are obtained by sedimentation and filtration. For some refractory ores or concentrates, preparation is often needed before leaching, so that the extracted metals can be converted into some compounds or salts which are easy to leach.

For example, in the process of sulfation and roasting, the impurities (unintended elements) in the metal solution are melted (heated to the melting point) to form slag and remove slag. At the same time, some chemical components can obtain relatively pure alloy composition through slag removal, decarburization and deoxidation. The refined refining process usually belongs to a metal foundry. Involving the metal forming industry, such as rough refining of ore processing and smelting (ferrous metal, non-ferrous metal); re processing of the blank, steel-making plant, ironmaking plant, purification of non-ferrous metal (generally reflected in the casting plant) are common preparation methods.