Abstract: Gelation time, polymerization rate of monosilicic acid, and growth of colloidal particles in the silicic acid systems with Mg2+ and Al3+ ions, which are intermediates in the preparation process of fine chemicals by metallurgical solid wastes, were investigated. The results showed that at pH<4, polymerization reaction in the systems was promoted by Mg2+ and Al3+. In the early stage, Al3+ obviously accelerated the polymerization reaction. Due to stronger ability to react with negative ions of silicic acid and OH-, the acceleration effect of Al3+ on polymerization reaction in the systems was stronger than that of Mg2+, and the effects of both Mg2+ and Al3+ were found in the range between that of Mg2+ and Al3+ ions existing itself alone. Growth of colloidal particles and silicon dioxide particles was also promoted by Mg2+ and Al3+, and Al3+ entered into the gel to replace Si forming tetrahedron. The obtained silicon dioxide particles were amorphous.

Key words: metallurgical solid waste, silicic acid, intermediate, polymerization behavior, gelation time, metallic ion

摘要： 对冶金固体废弃物精细化利用过程中中间体?含镁、铝离子硅酸体系中硅酸胶凝时间、单硅酸聚合速度及溶胶胶粒生长进行了研究. 结果表明，在pH<4的酸性范围内，Mg2+与Al3+离子促进硅酸的聚合反应，在反应初期Al3+已明显促进反应进行. 且Al3+与硅酸负离子、OH-的结合能力均强于Mg2+，其对硅酸的促凝作用较强；Mg2+和Al3+等浓度共存时，促凝效果介于单金属离子之间；Mg2+与Al3+促进了硅酸体系中溶胶胶粒的生长及SiO2粒子的长大，Al3+进入凝胶内部取代硅形成四面体配位；凝胶后所得SiO2为非晶态结构.

关键词: 冶金固废, 硅酸, 中间体, 聚合行为, 胶凝时间, 金属离子