乙酸盐对拜耳法脱硅产物析出行为的影响

摘要 研究了145℃下铝酸钠溶液中乙酸盐浓度对拜耳法脱硅产物矿相组成、微观组织和析出活性的影响规律.铝酸钠溶液中含有乙酸盐时，结晶水合铝硅酸钠主要由沸石和羟甲基方钠石组成，其晶格常数随着乙酸根浓度的增加而增加;随着乙酸根浓度的增加，沸石和羟甲基方钠石的结晶度逐渐降低，羟甲基方钠石的生成量逐渐增加，而沸石的生成量逐渐降低.乙酸盐对水合铝硅酸钠的微观形貌和官能团结构影响不大，但能提高水合铝硅酸钠的碱铝比，并降低硅铝比，使硅缺位程度增加;随着乙酸根浓度的增加，水合铝硅酸钠的粒度降低，在铝酸钠溶液中的活性增加.
Abstract：The effect of acetate concentration in sodium aluminate solution at 145℃ on the mineral composition， microstructure and precipitation activity of desilication products was studied. The results show that when the acetate exists in sodium aluminate solution， the crystalline sodium aluminosilicate hydrate is comprised of zeolite and methylol-sodalite and the corresponding lattice constant increases with the acetate concentration. Furthermore， with the increasing acetate concentration， the crystallinity of zeolite and methylol-sodalite reduces， and the content of zeolite decreases， in contrast with that of the methylol-sodalite. The effect of the acetate on the structure of functional group and microstructure of desilication products is very little. However， the additive of acetate can increase the molar ratio of Na2O to Al2O3 and decrease the molar ratio of SiO2 to Al2O3. Moreover， with the increasing acetate concentration， the particle size of desilication products decreases and the precipitation activity in sodium aluminate solution increases.