In metal extraction, a vast majority of metallurgical reactions are made to take place at elevated temperatures because than the ore compounds become relatively unstable, facilitating the release of the metal. This is the basis of pyrometallurgy. Pyrometallurgy deals with the methods of extraction of metals from their ores and their refining and is based on physical and chemical changes occurring at high temperatures, i.e. 500-2000°C.
Pyrometallurgical methods of metal production are usually cheaper and suited for large scale productions. Some of the noteworthy advantages of pyrometallurgy are:
- Reaction rates are greatly accelerated at high temperatures. So small units can achieve high production rates.
- Some reactions which are not thermodynamically possible at low temperature become possible at high temperatures.
- At high temperatures the products get melted or vaporized which makes easy, the physical separation of product metal from the gangue.Ex. Meta-Slag separation.
- Pyrometallurgy can bring about the reduction of a compound, which cannot take place in presence of water i.e. it has got ability to extract the reactive metals which can’t be reduced from aqueous solutions. Ex. Alkaline earth metals, zirconium, titanium etc.