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所谓“硅溶胶”是指具有大量相互离散的无定形二氧化硅粒子的稳定的分散体系。通常在室温下所得的酸化水玻璃溶液和硅酸酯(或卤化硅)的水解液,不属本章讨论的范畴。在加热至90～100℃的条件下,用酸中和稀释至0.1M以下的水玻璃溶液,虽可得含直径几纳米二氧化硅粒子的硅溶胶,但因这种硅溶胶中含有盐,故稳定性极差,一旦浓缩便会很快胶凝。目前国内外生产硅溶胶,是将由离子交换法所得的聚硅酸溶液在pH≈9,温度≈80℃的条件下令其进一步聚合而成胶体粒子,再浓缩成浓度达到工业要求
The term “silica sol” means a stable dispersion having a large amount of amorphous silica particles dispersed each other. Acidified waterglass solutions and silicate (or silicon halide) hydrolysates that are typically obtained at room temperature are beyond the scope of this chapter. Although a silica sol containing a few nanometers in diameter of silica particles can be obtained by neutralizing a water glass solution diluted to 0.1 M or less with an acid while heating to 90 to 100 ° C, It is very poor stability, once concentrated will gel soon. At present, the production of silica sol at home and abroad is that the polysilicic acid solution obtained by the ion exchange method is further polymerized into colloidal particles under the condition of pH≈9 and temperature of ≈80 ° C., and then concentrated to a concentration meeting the industrial requirement