Scope

Pyrometallurgy is that branch of extractive metallurgy which deals with the extraction of metals from their ores by thermal methods. Pyrometallurgy is the most important division of extractive metallurgy, since it is involved in the recovery of most metals. It is conveniently studied from two points of view: the chemical aspects and the engineering aspects. In pyrometallurgy, SiO₂ is considered an acidic oxide and CaO as basic oxide. This concept was introduced long ago when it was observed that some oxides dissolve in water forming an acid, and others when dissolved form a base. In pyrometallurgy, slags are produced in large quantities, either during the melting of ores or the refining of pig iron to make steel. The engineering aspects of pyrometallurgy can be conveniently divided into six unit operations: heat transfer, solid-gas separation, compaction of powders, oxidation of a solid phase, oxidation in a molten phase, and metallothermic reactions.