ABSTRACT
Metals are a natural resource but are seldom found in the native condition. Physical and chemical ingenuity therefore have to be used to extract metallic ores from the earth’s crust. The asmined ores then have to be concentrated, and the concentrate has to be smelted to produce a primary metal, which may then have to be refined by thermochemical or electrochemical processes. At each of these stages it is hoped that the impurities present in the original starting material will be removed so that the final product will be perfectly pure metal that can be used on its own or can be alloyed with other pure metals to produce materials to meet specific engineering demands.
