(1. 中南大學(xué) 化學(xué)化工學(xué)院，長沙 410083；
2. 蘭州大學(xué) 化學(xué)化工學(xué)院，蘭州 730000)
摘 要: 研究了在無超聲場及在20kHz和33kHz超聲場3種條件下的種分動力學(xué)方程。結(jié)果表明，在超聲場作用下進行種分過程，可以大幅度提高分解速度，縮短分解時間。在20kHz和33kHz超聲場中的種分動力學(xué)模型與無超聲場中的種分動力學(xué)模型一致，但是反應(yīng)的活化能分別降低了22kJ/mol和33kJ/mol。超聲場強化種分過程的機理是反應(yīng)體系吸 收了超聲場中的空化能量，降低了反應(yīng)的能量勢壘。
關(guān)鍵字: 超聲場；種分；動力學(xué)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
