Mechanism Of The Sedimentation Behavior Of Quaternary Ammonium Salts On Kaolinite、Diaspore And Quartz

The effect of pH, type of quaternary ammonium salts including DTAC (1231)、TTAC(1431)、CTAC(1631) on the ultrafine kaolinite, diaspore, quartz mineral settling behaviors are investigated by sedimentation tests. The aggregation mechanism of minerals was studied by Zeta potential measurements, determination of adsorption amount, SEM observations and DLVO theory calculation.Under the conditions of pH=6.7and pH=10, with the increasing concentration of quaternary ammonium salts, adsorption amount of quaternary ammonium salts on kaolinite and quartz surfaces rises, as well as Zeta potentials. The adsorption capacity of quaternary ammonium salts on kaolinite is stronger with a longer carbon chain. In pH=10conditions, diaspore shows the same adsorption rule with kaolinite and quartz.Under the conditions of pH=6.7and pH=10, the adsorption of1231and1431on kaolinite and quartz is driven by electrostatic interaction. The aggregation of minerals occurs for hydrophobic between alkyl chains. The aggregation is progressively bigger and tighter with higher concentration of1231and1431. Adsorption capacity of1631is stronger because of a longer carbon chain. Under the conditions of pH=6.7and pH=10, quartz particles aggregate in low concentration of1631solution. As1631concentrations continue to increase,1631forms double layer adsorption on silica surface and quartz particles gradually disperse. Under the conditions of pH=6.7, kaolinite particles partially disperse in solution of high concentration of1631and dispersion mechanism is similar to quartz.In quaternary ammonium salts solution, diaspore shows different settling behaviors compared with kaolinite and quartz. Under the conditions of pH=6.7, with the increasing concentration of1231, aggregation of diaspore particles enhances. While with the increasing concentration of1431and1631, diaspore particles gradually disperse. Under the condition of pH=10, with the increasing concentration of1231, diaspore particles would gradually aggregate after dispersion; with the increasing concentration of1431, the aggregation of diaspore particles enhances; with the increasing concentration of1631, diaspore particles would gradually disperse after aggregation.