Cement clinker is a semi-finished product obtained by using limestone, clay, and iron as the main raw materials, prepared into raw materials in an appropriate proportion, burned to partial or full melting, and cooled. It is mainly composed of CaO.SiO2.Al2O3 and Fe2O3, and the sum of its content is usually more than 95%. The main application of clinker is to produce cement.
The difference between ordinary Portland cement and Portland cement is that there are a small amount of mixed materials in the platform, and most of them are still silica salt cement clinker, so its basic properties are the same as Portland cement. Compared with the silica salt cement of the same label, the early hardening speed of ordinary silicate is slightly slower, and its 3d>d compressive strength is slightly lower than that of Portland cement. The properties of frost resistance and abrasion resistance are also slightly worse than Portland cement. Ordinary Portland cement has a wide range of labels, which is convenient for reasonable selection.
The hydraulic cementing material made of Portland cement clinker and viscous blast furnace slag, added with appropriate amount of gypsum, is called slag Portland cement. The addition amount of blast furnace slag in the cement is 1t—20-70% by weight. The requirements for the degree of crease, setting time and volume stability of portland cement are the same as those of portland cement.
Advantages: low heat of hydration, good sulfate resistance; good heat resistance; steam curing has a good effect.
Disadvantages: low strength in the early stage, large increase in strength in the later stage; poor water retention and poor ice resistance. ,
In the Portland cement clinker, 20-50% pozzolanic mixed material and appropriate amount of gypsum are added according to the weight of the finished cement product, and it is made after grinding.
Advantages: good water retention; low heat of hydration. Good resistance to sulfate attack.
Disadvantages; water demand, high drying shrinkage; low early strength; high late strength increase rate; poor ice resistance.
In the Portland cement clinker, 20-40% coal ash and appropriate amount of gypsum are added according to the weight of the finished cement product, and it is made after grinding.
Advantages: low heat of hydration; good resistance to sulfuric acid; can improve the workability of mortar and concrete.
Disadvantages: the early strength is low and the later strength increase rate is large; the frost resistance is off.
Clinker grinding equipment recommendation: Shanghai ZENITH LM N series vertical roller mill. This series mill is a new type of milling equipment with advanced technology, excellent performance and drying function. It integrates the functions of drying, grinding and powder selection, used in cement, chemical industry, coal, electricity and other industries, and it has gradually become the mainstream equipment in the grinding industry.