Hydrometallurgy

Hydrometallurgy as a word is derived from the Greek hýdōr, meaning water. It refers to the technique of extracting metal from an ore or another material by creating an aqueous solution of a salt of the metal and then recovering the metal from the solution. It is an approach that uses both technology and chemistry to recover metals from a wide variety of metal-bearing sources, which include recycled materials, waste streams, intermediates, mineral concentrates, ores and other solutions.

Hydrometallurgy involves three processes:

• Leaching - which means to drain away from and involves various process such as autoclave, column, atmospheric and pressure acid depending on the metal ore.
• Recover - which refers to the extraction of previously processed metals by methods of carbon-in-leach, carbon-in-pulp, oxidation through a biological approach or using pressure and cementation.
• Solution purification - which refers to the physical separation of the metal from a solution through ion-exchange, direct solvent extraction, electrowinning, or precipitation (also classified as electrometallurgy).

It is a one of the three branches of metallurgy, with the others being pyrometallurgy and electrometallurgy. The three main types of pyrometallurgy might be considered as being calcination, roasting and smelting.

[edit] Related articles on Designing Buildings

• Carbonation.
• Electrometallurgy.
• Pyrometallurgy.
• Roasting.
• Metal in construction.
• Metallurgy.
• Types of metal.
• Types of steel.