Composition and general characteristics of limestone: limestone mineral composed mainly of calcite (the main component is CaCO3), metallurgical lime offer, accompanied by dolomite, magnesite and other carbonate minerals, metallurgical lime, also mixed with other Some impurities. Limestone has a good workability, polished and well cementing properties, insoluble in water, high-quality metallurgical lime, soluble in acid, can react with a variety of strong acids and the formation of the corresponding calcium salt, and release CO2. Limestone particle size (fineness) on the FGD system performance: ground limestone powder can increase the surface area per unit mass of limestone powder, while maintaining the same pH and the same absorption tower desulfurization rate, FGD system at a high limestone utilization running conditions, the quality of gypsum by-product will be better.