Lime: for steelmaking, the particle size of the active lime requirement is to ensure that the requirements of steel-making process at the time of slagging speed and effectiveness. If the lime particle size is too large, the reaction time will lead to lime particles and molten steel is lengthened, so slow down and affect slagging slagging effect. Conversely, if the particle size is too small lime, at the time of steelmaking dust particles or splashes easily cause deteriorated operating environment. Many different types of limestone steel with lime, generally common: granular crystalline limestone, dense limestone, porous limestone, earthy limestone, marly limestone, chalk, dolomite, shell - limestone river pebbles and so on. Because the chemical composition of steel in the main activity of lime with lime factory, to CaO (calcium oxide) content have higher requirements of quality steel with lime, the general should be more than 90%. Meanwhile, the S (sulfur), the content of P (phosphorus) and other impurities have the smaller the better requirements. Therefore, the raw material for the production activity of lime - quality limestone is clearly required.