Slag is the chemical compound resulting during the smelting of metallic ores. It results because of the action of the flux on impurities in the ore. Slag generally consists of silicates, formed by the combination of silica with alumina, lime, magnesia, oxides of iron or other metals. By the formation of slag, the impurities in the ore are removed, and if the metallic contents of the slag are of no value the slag is regarded as smelters' refuse. Some slags, however, consisting mainly of metallic oxides produced during the refining processes, are resmelted and such slags are termed cinder or scoria. As slag has to be separated from the valuable metallic material, its fluidity, at the smelting temperature, is an important factor, and some substances such as an oxide of zinc are apt to make slags pasty.
Slags vary in chemical composition, but those which crystallise are regarded as definite chemical compounds. The colour of slags affords n indication of the composition, for example green denotes the presence of iron and copper oxide produces a red slag. Slags are used for various purposes, as ballast for railways, macadamising roads, making into bricks and others. Some slags may be burnt with lime, thus making an efficient hydraulic cement, and slag from the basic Bessemer process forms a fertiliser containing phosphorus. Research Slag
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Abbreviations
SciTech
Research Slag
