摘要
利用含镁、铝盐的有盐硅酸体系,以氨水调节其pH,加入分散剂及表面改性剂,制备出平均粒径为60nm左右的白炭黑样品,通过此体系的pH值与所制样品比表面积的关系,探讨了有盐体系中硅酸的聚合机理,发现:当pH<3.8时,随pH升高,硅酸聚合度减小;在pH≈3.8时聚合度达到最小值;pH>3.8时,因Al3+、Mg2+的水解,各产物离子的羟基配位能力未达饱和,易与硅酸之间发生配位使聚合度逐渐增大,这种趋势随pH值进一步增大而逐步减弱。
Nano-silica white was prepared from salt system containing silica, Al^3＋ and Mg^2＋, in this preparation process some dispersant and surface modifying agent were applied and ammonia was used to adjust the pH of the solution. The mean diameter of the obtained product is 60nm. The relationship between pH of the system and the specific surface area of silica white obtained was investigated. Then the polymerization mechanism of silica white was discussed on the basis of the relationship. It was found that the polymerization degree of silica decreased with the increasing of pH value when pH〈3.8; and when pH〉3.8, the hydroxyl of ions, produced by hydrolyzation of Al^3＋ and Mg^2＋, was prone to react with silica because of their superfluous ability to form complex, which will make the polymerization degree increase. But the trend of reaction would weaken with the increasing of pH value. Therefore the polymerization degree of silica was minimum when pH ≈ 3.8.
出处
《有色冶金设计与研究》
2007年第2期255-257,266,共4页
Nonferrous Metals Engineering & Research
关键词
有盐体系
聚合
纳米白炭黑
salt system
polymerization
nano-silica white
