Zeta potential simulation of kaolinite particle surface in different Ca~(2+) concentration and pH value suspension

It is difficult to settle down kaolinite particles in the coal slime water due to their stable surface charge.The Ca2+ concentration and pH value has a comparatively large effect on kaolinite surface Zeta potential in aqueous solution.Based on the different charge mechanism on different fracture surface of kaolinite,the total-surface Zeta potential model was established by the crystal cell number of different kaolinite fracture surface as weight,and adjusted by the fitting.The kaolinite surface Zeta potentials was simulated by the model above.The kaolinite surface Zeta potentials was also measured by the electrophoresis method.The results show that the model could effectively predict kaolinite surface Zeta potential when the Ca2+ concentrations is more than 25 mg/L and the pH less then 9.The maximum deviation is 1.368 mV.The prediction accuracy reduced when Ca2+ concentration is less than 25 mg/L because of increasing of negative charge on the kaolinite surface.The prediction accuracy reduced when pH value is more than 9 because of Ca2+ complexion adsorption.