外加晶种对钛白粉水解过程及其亮度的影响

Influence of crystal seeds amount on hydrolysis process of rutile titanium dioxide and its brightness

以工业浓缩钛液为原料,采用外加晶种水解工艺制备金红石型二氧化钛,考察了晶种不同添加量对水解率、一次团聚粒子、煅烧二氧化钛晶体形貌以及一次团聚粒子粒径与颜料性能亮度的关系。结果表明,当水解晶种添加量为钛液所含二氧化钛质量的3.0%时,硫酸氧钛的水解率高达95.4%,一次团聚粒子粒径约为43 nm,煅烧二氧化钛呈短圆柱状,此时亮度为94.4。说明外加晶种在引发硫酸氧钛水解的同时,影响原级粒子间的相互作用,降低了一次团聚粒子的平均粒径,并影响了一次团聚粒子的再团聚,从而降低了一次团聚粒子的再团聚倾向。在此条件下,煅烧后二氧化钛的粒径减小、粒径分布更为均匀,进而提高了煅烧二氧化钛的亮度,改善了其颜料性能。

Rutile titanium dioxide was prepared by seedadding hydrolysis method with industrial condensed titanyl sulfate solution as raw material.The influences of crystal seeds adding amount on hydrolysis yield,the particles of primary agglomerate,the micrographs of calcined titanium dioxide crystal,as well as the relationship of the mean size of primary agglomerate and pigment brightness characteristics were investigated.The results showed that when the hydrolysis seeds adding amount was 3.0%(mass fraction)of titanium dioxide in condensed titanyl solution,the hydrolysis yield of titanyl sulfate was as high as 95.4%,the mean size and brightness of primary agglomerate were about 43 nm and 94.4 respectively,and calcined titanium dioxide had a morphology of short cylindrical.This showed that crystal seeds induced the hydrolysis process of titanyl sulfate,affected the interaction between the primary particles of metatitanic acid,decreased the mean size of primary agglomerate,and influenced the recoalescence of primary agglomerates.Thereby the particle size of calcined titanium dioxide was decreased,its size distribution was narrowed,and its brightness and pigment property were both improved.