Effect of combined grinding aid on quartz grinding and its mechanism

In order to improve the grinding efficiency of quartz, the grinding aids sodium silicate and sodium hexametaphosphate are combined to study the influence mechanism of quartz grinding.During grinding, when the optimal addition of combined grinding aid is 0.5%, the -0.043 mm particle size content in the grinding product is increased by 9.90%, 3.34% and 2.23% respectively compared with the helpless grinding agent, sodium silicate and sodium hexametaphosphate, which significantly improves the grinding efficiency of quartz.It is found that the combined grinding aids significantly reduced the viscosity of the pulp and improved the dispersion and fluidity of the pulp.The infrared spectroscopy, XPS surface element analysis and solution chemistry show that quartz is activated by calcium ion in the grinding water at pH=9.89, and the combined grinding aids are mainly active substances of and HSO^3-, resulting in chemisorption on Si-O-Ca⁺ active sites on the surface of quartz activated by calcium ions.Quantum mechanical calculation shows that the combined grinding aid has stronger adsorption on the surface of activated quartz, and the specific surface energy of quartz can be significantly reduced by its adsorption.The results show that the combined grinding aids can obviously improve the grinding efficiency of quartz compared with the two single grinding aids.