摘要
Surface tension of sodium aluminate solution and the contact angle between Al（OH）3 particles and aluminate solution were measured, then the dependence of Al（OH）3 solubility on its particle size was calculated and thus the variation of the critical nucleus sizes was determined based on the Ostwald ripening formula. The results show that the Al（OH）3 solubility in sodium aluminate solution decreases with the increment of particle size, and the critical nucleus sizes increase with the rise of alkali concentration, caustic ratio and precipitation temperature. The results also imply that the presence of small particles in seeded precipitation system is an important factor to limit the depth of precipitation.
在铝酸钠溶液晶种分解过程中提高分解率与改善产品质量之间存在难以调和的矛盾,因此研究铝酸钠溶液中氢氧化铝的溶解度与颗粒尺寸的关系是很有必要的。采用红外光谱仪、表面张力仪及接触角仪,测定和计算了Al(OH)3颗粒与铝酸钠溶液的固液界面性质,并结合Ostwald熟化公式,对铝酸钠溶液中Al(OH)3溶解度与其颗粒尺寸之间的关系以及临界核尺寸的变化规律进行了分析。结果表明:三水铝石细粒子的溶解度大于粗粒子的溶解度,且其临界核尺寸随着碱浓度、苛性比及温度的升高而增大,细粒子的存在是限制晶种分解程度的重要因素。
基金
Project(51274242)supported by the National Natural Science Foundation of China
