The process by which metals are extracted easily and economically from their ores and refining them to a pure state is called Metallurgy. It includes many chemical and also physical operations. It also includes the preparation of alloys.
Minerals and Ores: The compounds of metals that exists in nature are called minerals. All minerals are not suitable for the extraction of metals. Only those minerals from which a metal can be extracted in an economically profitable way are called ores. Thus, we can say that all ores are minerals but all minerals are not ores.
Gangue or Matrix: The ores of metals are invariably associated with earthy or rocky materials as impurities called Gangue or Matrix.
Flux: A flux is a substance that is added to the furnace charge during smelting operation to remove gangue forming a fusible body called slag.
Flux + Gangue = Slag
The selection of flux depends upon the nature of gangue or impurities. it must be acidic to remove basic impurities and basic to remove acidic impurities.
Slag: The fusible compound formed by the union of the flux and the impurities, especially when it is the waste product of an operation is termed ‘Slag‘. Slag finds valuable uses in the industry.
Slag = Flux + Impurities