冶金固体废弃物精细化利用过程中中间体的聚合行为

Polymerization Behavior of Intermediates in the Preparation Process of Fine Chemicals with Metallurgical Solid Waste

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.

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.