(1. 中南大学 化学化工学院，长沙 410083；
2. 兰州大学 化学化工学院，兰州 730000)
摘 要: 研究了在无超声场及在20kHz和33kHz超声场3种条件下的种分动力学方程。结果表明，在超声场作用下进行种分过程，可以大幅度提高分解速度，缩短分解时间。在20kHz和33kHz超声场中的种分动力学模型与无超声场中的种分动力学模型一致，但是反应的活化能分别降低了22kJ/mol和33kJ/mol。超声场强化种分过程的机理是反应体系吸 收了超声场中的空化能量，降低了反应的能量势垒。
关键字: 超声场；种分；动力学方程；活化能
aluminium trihydroxide precipitation
Bayer process
（1. College of Chemistry and Chemical Engineering，
Central South University，Changsha 410083, China;
2. College of Chemistry and Chemical Engineering，
Lanzhou University, Lanzhou 730000, China）
Abstract:The precipitation rate is increased and the precipitation time is reduced remarkably under ultrasound. The kinetic model of precipitation without ultrasound is in accordance with those of other researches. It is a second order rate equation model that relates the instantaneous rate of hydrate precipitation to the supersaturation of sodium aluminate solution. The activation energy found in experiments is 68kJ/mol, closing to the values published before. Furthermore, the kinetic models of precipitation under 20kHz and 33kHz ultrasound are the same as those without ultrasound, with exception of activation energies reduction and the frequency factors changed. Compared with the activation energy without ultrasound, it is reduced by 33kJ/mol and 22kJ/mol under 33kHz and 20kHz ultrasound respectively.
Key words: ultrasound; precipitation; kinetic model; activation energy
