ABSTRACT
The unit operation is concerned with the preparation of metals and alloys by reduction of their oxides or halides with metal. Metallothermic reactions are batch processes in which both reactants are solids. The powdered feed material, the reducing metal powder, and any necessary additive are thoroughly mixed before charging into the reactor. Solid-solid reactions may be exothermic or endothermic. In the exothermic system, the reaction takes place in such a way that when the mixture is ignited at one place, the reaction continues to go on spontaneously usually with the formation of a fluid slag, and the reduced metal is obtained as a compact uniform regulus. When the reducing metal has a high vapor pressure, the reaction must be conducted in a pressure reactor. Small amounts of salt adhering to the metal are usually removed by vacuum evaporation.
