为排除Na+对硅酸聚合的影响，用酸解水淬硅酸钙制备了不含金属离子的硅酸溶液及含Ca2+, Al3+的硅酸溶液，研究了加入Ca2+, Al3+对体系聚合行为的影响. 结果表明，加入Ca2+后体系pH值略微降低，加入Al3+后体系pH值显著降低. 初始pH≤2时，Al3+对硅酸聚合起促凝作用，初始pH>2时，Al3+起缓凝作用. Ca2+对硅酸聚合影响不大. 硅酸凝胶后，含Al3+硅酸体系中形成Al?O?Si键，阻碍了凝胶结构水脱附；Ca2+则阻碍凝胶的晶化转变过程，且凝胶中的结构水变少. 不含金属离子、含Ca2+、含Al3+体系的化学式分别为SiO2×0.52H2O, SiO2×0.36H2O, SiO2×1.50H2O.

To eliminate the effect of Na+ on the polymerization of silicic acid, silicic acid without any metal ions was prepared by acid hydrolysis of water-quenched calcium sillicate. After adding Ca2+, pH value of silicic acid slightly decreased, while it significantly decreased after adding Al3+. The polymerization rate of silicic acid is accelerated by Al3+ at initial pH≤2, but reduced at initial pH>2. As for Ca2+, it had no obvious effect on polymerization of silicic acid. After gelation, Al?O?Si bond was formed in the silica gel, which hindered dehydration of bound water. The crystallization process was hindered by Ca2+, and the amount of bound water decreased. The chemical formulas of silica gels with no ions, Ca2+ and Al3+ are SiO2×0.52H2O, SiO2×0.36H2O, SiO2×1.50H2O, respectively.