Hydrometallurgy or leaching is one of the most common methods of extracting some metals from minerals, which includes the use of mineral chemistry and organic chemistry to recover metals from minerals, concentrates and recycled materials or residues and waste.

Hydrometallurgy is usually divided into three general parts:

• Leaching: It involves the use of solutions to extract metal from its carrier materials. The five most common extraction methods in this way are: tank leaching, heap leaching, wet leaching (Ghargabi leaching), autoclave leaching and mining leaching (In-situ).

• Concentration of the solution and purification: after leaching, usually the resulting solution must be enriched so that either the concentration of the metal ions in it reaches the optimal level for recovery and extraction, or the undesirable metal ions are removed from the solution. Sedimentation, cementation, liquid-liquid extraction and ion exchange are some of the distillation techniques that are investigated and used in the design of the production line depending on the type of materials, facilities, costs and purpose of doing it.

• Extraction of metal or metal composition: The last stage in a hydrometallurgical process is the stage of extracting the metal to be presented to the market and sold. Of course, sometimes other processing steps are needed if a metal with very high purity is needed. The primary types of metal extraction are electrolysis, sedimentation and gas reduction methods.