高浓度铝酸钠溶液晶种分解动力学
来源期刊：中南大学学报(自然科学版)2004年第4期
论文作者：周秋生 李小斌 彭志宏 刘桂华 赵清杰 吴洁
文章页码：557 - 561
关键词：铝酸钠溶液;浓度;分解;动力学
Key words：sodium aluminate solution; concentration; precipitation; kinetics
摘 要：引入瞬时晶种系数Krt,以[(ρ-ρc)/ρf]n2为过饱和铝酸钠溶液晶种分解过程的推动力,导出了高浓度铝酸钠溶液晶种分解过程的动力学方程,得到在高浓度条件下晶种分解过程的表观活化能为30.84 kJ/mol。应用所导出的动力学方程,对分解温度、苛性碱浓度、过饱和度等因素对高浓度条件下晶种分解过程的影响进行模拟分析,研究结果表明:由于该过程的控制方式由铝酸钠溶液较低浓度时的表面化学反应控制转变为高浓度的扩散控制或混合控制,从而导致铝酸钠溶液高浓度时的活化能明显低于其较低浓度时的活化能。
Abstract: By introducing instantaneous seed coefficient and taking [(ρ-ρc)/ρf]n2 as the driving force of the seeded precipitation from sodium aluminate solution with high concentration, a kinetics equation of precipitation including the effects of seed coefficient and super-saturation of solution on the precipitation was deduced in this paper. The obtained apparent activation energy of this process is 30.84 kJ/mol, which is much smaller than that of the sodium aluminate solution with lower concentration reported in literature. The reason is that the controlling process changes from the surface chemical reaction controlling process of the lower sodium aluminate concentration to the diffusion controlling process or the mixed controlling process of the high sodium aluminate concentration. In addition, the influences of temperature, caustic soda concentration and super-saturation on the seeded precipitation were analyzed by the acquired kinetics equation.
