Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores.  Hydrometallurgy involve the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual materials. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy.  Hydrometallurgy is typically divided into three general areas:
*Leaching
*Solution concentration and purification
*Metal or metal compound recovery