A gray limestone to calcium oxide gas rigid inorganic cementitious material as a main component. Lime is a product with a high content of calcium carbonate limestone, dolomite, chalk, shells and other Anyang limestone, calcination by 900 ~ 1100 ℃. Lime is the first human application of cementitious material. Effect of limestone composition of wet flue gas desulfurization properties: Henan usually limestone, calcium carbonate in limestone weight percentage should be higher than 85% of Tianjin limestone powder, due to impurities and to bring some of the content is too low to run problems, resulting in increased consumption and transportation costs absorbent, gypsum purity decreases. China is rich in limestone resources, CaCO3 content of the limestone FGD system uses most of the power plants of more than 90%.