高分散纳米沉淀白炭黑的制备

Preparation of highly dispersed nanometer silica

以液体水玻璃为原料,通过化学沉淀法并在制备过程中加入适量表面分散剂对白炭黑进行分散,得到了高分散纳米沉淀白炭黑。经实验筛选确定较佳的分散剂为D-葡萄糖酸钠,对其机理做了分析,并以水玻璃中的收率为考察指标,通过单因素实验分别考察了沉淀反应温度、陈化时间、硅酸钠溶液浓度、CO_2流率等因素对Si O_2收率的影响。实验得到最佳工艺条件:反应温度为85℃、陈化时间为1 h、硅酸钠溶液质量分数为11%、CO_2流率为80 m L/min。在此条件下重复实验结果 ,Si O_2平均收率为99.67%左右,平均粒径为20~40 nm,分散性有了明显的提高。

Highly dispersed nanometer silica was obtained via chemical precipitation method by adding right amount of surface dispersant using soluble silicate as raw material.D-sodium gluconate was proved the best dispersant and its working mechanism was analyzed in detail by screening experiment.Taking the yield of Si O2 as the main reference index,the precipitation conditions,such as precipitation temperature,ageing time,concentration of soluble sodium silicate and flow rate of CO2,were investigated via single-factor experiments.The optimized precipitation conditions were as follows：reaction temperature was 85 ℃,ageing time was 1 h,mass fraction of soluble sodium silicate was 11%,and flow rate of CO2 was 80 m L/min.The repeated experiments showed that the average yield of Si O2 could reach about 99.67% under the optimized precipitation conditions and the as-obtained sample had average particle size of 20-40 nm with better dispersity.