不同条件对铝包覆钛白粉水分散稳定性的影响

Effect of the preparation conditions of alumina-coated titanium dioxide on aqueous dispersion stability

以硫酸铝溶液为包覆剂,采用并流沉淀法,研究反应p H值、反应温度、熟化时间及包覆量对钛白粉包覆氧化铝分散稳定性的影响规律,优化了包覆工艺;采用Zeta电位分析仪、透射电子显微镜以及电感耦合等离子体质谱仪对包覆产品表面电性、微观形貌及成分进行了表征。结果表明:得到高分散稳定性包覆产品的优化工艺条件是反应p H为9,反应温度为70℃,熟化时间为120 min,包覆量为3.2%;优化工艺条件下,包覆后的钛白粉比表面积由6.73 m^2/g增大至18.28 m^2/g,吸油量由19.88 g/m L增至32.46 g/m L;产品表面形成均匀连续絮状包覆层,增强了钛白粉颗粒的表面电性,颗粒间静电斥力增大,水分散稳定性能得到了显著改善。

Taking aluminum sulfate solution as coating agent, the effect of pH value, temperature, aging time and coating quantity on the dispersion stability of alumina-coated titanium dioxide was studied through the parallel flow precipitation process. The surface property, microstructure and component of the coated samples were characterized by Zeta potential analyzer, TEM and ICP-MS. The results show that the optimal conditions for coated samples with high dispersion stability are as follows： the pH is 9, the temperature is 70 ~E, the ageing time is 2 and the coating quantity is 3.2%. The specific surface area of coated titanium dioxide is increased from 6.73 mVg to 18.28 mVg and the oil-absorption value is improved from 19.88 g/mL to 32.46 g/mL under the optimal conditions. On the other hand, the flocculent coating layer on the coated samples is uniform and continuous. The surface property ,the electrostatic repulsion between particles and the dispersion stability in aqueous dispersion system were improved remarkably.