从铝酸钠溶液中析出一水软铝石的实验研究

来源期刊：中南大学学报(自然科学版)2006年第1期

论文作者：李小斌 潘军 刘桂华 彭志宏 周秋生

文章页码：25 - 30

关键词：铝酸钠溶液;晶种;一水软铝石;分解率

Key words：sodium aluminate solution; seeded precipitation; boehmite; the ratio of seeded decom- Position

摘    要：通过热力学分析确定了铝酸钠溶液体系中三水铝石、一水软铝石平衡固相与温度和苛性比之间的关系。以三水铝石为前驱体,通过水热法处理,制得结晶良好、纯度较高的一水软铝石;升高温度,延长反应时间,减小前驱体粒度以及加入适量苛性碱都有利于三水铝石向一水软铝石的转变。以一水软铝石为晶种分解铝酸钠溶液的实验结果表明:分解原液浓度升高,分解率降低;晶种粒度减小,分解时间延长,分解率升高;在95℃,铝酸钠溶液只析出一水软铝石,且最大分解率可达43.19%;而在85℃以下,分解产物为三水铝石。实验结果与理论分析结果相吻合。

Abstract: Through the analysis of thermodynamics, relationship between equilibrium phase of thihydrate and boehmite with temperature and caustic mole ratio in the system of sodium aluminate solution was determined. The perfect crystal and pure boehmite was synthesized by hydrothermal process using thihydrate as precursor and it was propitious to conversing from thihydrate to boehmite when the temperature increased, the reaction time prolonged and the granularity of precursor decreased. Using boehmite as a seed to precipitate sodium aluminate solution, the results of seeded precipitation show that the ratio of seeded decomposition reduces when the concentration of decomposition solution increases; the ratio of seeded decomposition increases when the granularity of seed decreases and the time of seeded decomposition is prolonged. Sodium aluminate solution only precipitates boehmite and the largest ratio of seeded decomposition reaches 43.19% when the temperature is above 95℃; whereas the product of precipitation is thihydrate when the temperature is below 85℃. The experiment results are in good accordance with theoretical analysis.