CaO对铝酸钠溶液常压脱硅的影响

Effect of CaO on Atmospheric Pressure Desilication of Sodium Aluminate Solution

利用XRD和SEM-EDS等检测手段系统分析了铝酸钠溶液常压脱硅过程中脱硅产物的生成量、物相组成和微观形貌,研究CaO在脱硅过程中的反应行为。研究结果表明,随着钙硅比和脱硅时间的增加,脱硅产物的生成量逐渐增加,脱硅产物主要包括六水合铝酸钙、水化石榴石、沸石和A型沸石四种物相;钙硅比和脱硅时间的增加,有利于脱硅产物六水铝酸三钙向水化石榴石转化,同时脱硅产物的晶格常数和晶胞体积不断增加;不同类型脱硅产物微观形貌差异较大,脱硅产物物相析出次序依次为六水铝酸三钙、水化石榴石、A型沸石、沸石。

The reaction behavior of CaO during desilication process of sodium aluminate solution was systematically investigated by analyzing the producing quantity, phase composition and morphology of desilication products with XRD and SEM-EDS methods.The results show that the amount of desilication products rise gradually with the increase of calcium ratio and reaction time.The desilication products mainly include four phases, i.e.,tricalcium aluminate hexahydrate, hydrogarnet, zeolite-A and zeolite.The increasing of calcium ratio and reaction time is beneficial to the conversion of desilication products tricalcium aluminate hexahydrate to hydrogarnet, and the corresponding lattice constant and unit cell volume of desilication products increase continuously.The morphology of different types of desilication products is quite different, and the precipitation sequence of desilication products is as follows: tricalcium aluminate hexahydrate, hydrogarnet, zeolite-A,and zeolite.