The production process of building materials cement is divided into three stages, and it is customary to call the cement production process "two grinding and one burning":
The first stage: raw meal grinding. Crushing or drying, mixing and grinding calcareous raw materials, clayey raw materials and a small amount of correction raw materials (a certain amount of coal will be added in vertical kiln production) according to a certain proportion to prepare raw materials with appropriate components and uniform quality;
The second stage: clinker calcination. Adding raw materials into a cement kiln and calcining until partial melting to obtain cement clinker with calcium silicate as the main component;
The third stage: cement grinding. Appropriate amount of gypsum is added to the clinker, and sometimes some mixed materials are added and ground into cement.
Among them, the assets of the first two processes are heavy, and the general production line is located near limestone mines. Cement grinding has less investment and is more flexible, and is generally located near the market.
Raw material price:
Judging from the price of raw materials, limestone is cheap and has little fluctuation. According to the statistics of the Geological Center of the former National Bureau of Building Materials, the distribution area of limestone in China accounts for about 1/20 of the land area, and limestone resources that can be used as cement raw materials account for about 1/4 ~ 1/3 of the total resources. Because limestone is widely distributed in China and easy to mine, the price is relatively low, about 60~ 100 yuan/ton.