Cement Raw Materials
Cement is a technological material used by mankind in various fields, especially in construction and civil engineering. The production of cement mainly uses various raw materials.
Cement raw materials mainly include limestone, clay, sand, iron ore and other raw materials. Generally, cement factories purchase more limestone. The reason is that limestone is the main raw material for cement production, accounting for 70%-80% of the raw material volume. The main components of limestone are calcium carbonate and some other components such as magnesium carbonate, silica and alumina. The main feature of limestone is that its potential acidity increases the melting point of cement.
In the process of cement production, clay is also a necessary raw material for preparing iron ore and calcium silicate. Therefore, clay is also an important raw material for cement production, accounting for about 15%-20% of the raw material volume. Clay usually contains quartz, mica, iron oxides and other impurities, and it needs to be decolorized and purged with lime before being used in the production of cement.
Sand is also an important raw material in the production of cement, especially in the production of silicate cement. Sand accounts for 5%-10% of the total raw material and is used to adjust the composition and fineness of cement. Iron ore is also one of the raw materials, accounting for 2%-5% of the total raw material, which is added to the clinker to improve the quality of cement. Other raw materials allowed in the production of cement such as alumina, sulfate, slag, etc. Depending on the strength, color and other requirements of the cement, the most suitable one is selected.
In the process of producing cement, in order to reduce energy consumption and air pollution, various fuels such as natural gas, petroleum coke and coal are preferably used, and their proportion in the raw material does not exceed 5%. These fuels are used to dry, preheat and heat the raw materials in the production process, thereby improving the energy efficiency of the production.
In the production of cement, the use of various raw materials is in accordance with the total cements of various cements, so as to ensure the physical and chemical index of clinker. It also needs to be transported in advance and pre-stored. The raw materials shall pass strict physical and chemical index test, and then be sent to the factory of cement clinker after being proportionally sent. Finally, they are prepared in the mill and sent to the kiln system to produce cement clinker.
