Cement grinding aid
Cement grinding aid is a chemical additive that improves the grinding effect and performance of cement grinding. It can significantly increase the output of cement platform, the strength of cement at various ages, and improve its fluidity. The cement grinding aid can greatly reduce the phenomenon of electrostatic adsorption ball formation formed during the grinding process, and can reduce the re-agglomeration tendency of the ultrafine particles formed during the grinding process. The cement grinding aid can also significantly improve the fluidity of the cement, improve the grinding effect of the mill and the powder selection efficiency of the classifier, thereby reducing the energy consumption of the grinding. The cement produced by the grinding aid has a lower tendency of compaction and coalescence, which is beneficial to the loading and unloading of the cement and can reduce the wall hanging phenomenon of the cement storage. As a chemical additive, grinding aids can improve the distribution of cement particles and stimulate hydration power, thereby increasing the early strength and late strength of cement.
The first argument is that the adsorption of the grinding aid molecules on the particles reduces the surface energy of the particles or causes the misalignment of the near-surface layer crystals, causing point or line defects, thereby reducing the strength and hardness of the particles, promoting the generation of cracks and Expansion.
The second argument is that the grinding aid can reduce the viscosity of the mineral material and promote the dispersion of the particles by adjusting the fluidity of the mineral material and the surface electrical properties of the particles, thereby improving the flowability of the mineral material and preventing the particles from being in the grinding medium. And adhesion on the mill liner and agglomeration between the particles.
Common cement grinding aids are liquid and powder (solid), which can significantly increase mill output, or improve product quality, or reduce grinding power consumption. The cement grinding aid in the wet grinding process is also called: dispersing agent.
Cement grinding aid composition
According to the chemical structure classification, cement grinding aids can be divided into three types: polymeric organic salt grinding aids, polymeric inorganic salt grinding aids and composite compound grinding aids. Most of the cement grinding aid products used are organic surfactants. Due to the high price of the one-component grinding aid, the use effect is not very satisfactory, and the composite compound grinding aid is widely used.
Liquid cement grinding aid component
The components of liquid cement grinding aids are often: liquid grinding aid mother liquor, triethanolamine, polymeric polyol, polymeric alcoholamine, triisopropanolamine, ethylene glycol, propylene glycol, glycerol, sodium fatty acid, calcium chloride. , sodium chloride, sodium acetate, aluminum sulfate, calcium formate, wood calcium, sodium sodium and the like.
The quality of cement grinding aids should meet the requirements of building materials industry standard GB/T26748-2011. The national standard "General Portland Cement" stipulates that when grinding cement, it is allowed to add grinding aid, the amount of addition should not exceed 0.5% of the quality of cement; the new national standard also increases the requirement of chloride ion limit, namely: The chloride ion content of the cement should not exceed 0.06%.