The Impact Of Ultrasound On The Crystallization Process Of Copper Sulfate

The isothermal crystallization process of cupric sulfate solution is investigated. The effect of output power, frequency, time of ultrasound and the temperature of bulk solution on the induction time, crystallization speed, and the crystal were studied. And the aim of the research is to provide theoretical parameters and technical supply to the application of ultrasound in industry.1. The effects of ultrasound on the induction timeCuSO₄ supersaturated solution under 35.0℃was taken as the research system, the change rule of the induction time is investigated and the reseach result indicated: The introduction of ultrasound in the CuSO₄ solution isothermal crystallization process, may obviously reduce the induction time of the cupric sulfate solution. When the frequency is 24.4 kHz and the power is 80W, the induction time is 15s, however, the induction time is 4320s under silent conditions When the frequency is invariable, increases the power, the induction time decreases with the increase of the power. When the frequency is 24.4 kHz and the power increases form 30W to 80W, the induction time reduces from 218s to 15s. When the frequency is 80.0 kHz and the power increases form 30W to 60W, the induction time reduces from 1350s to 998s. When the power is invariable, the induction time increases with the increase of frequency. It is obvious that the induction time effectively reduced. When the power is 30Wand the power increases form 24.4 kHz to 80 kHz, the induction time increases from 218s to 1358s.2. The effects of ultrasound on crystallization speedIn supersaturated solutions of CuSO₄ at 35.0℃, the dependence of recovered quality on reaction time under different sonicated conditions was investigated. It is found that:The ultrasound can accelerate the primary nucleation, the second nucleation, strengthen the process of mass transfer and the heat transfer, and enhance the crystallization rate of CuSO4 solution.The increased power may enhance the crystallization rate. When the frequency is 40.0 kHz and the power increases from 30W to 80W, the crystallization quality changes from 0. 0.4151g to 0.7359g at 10s. The increased frequency causes the crystallization rate to reduce, When the power is 30W and the frequency increases from 24.4 kHz to 80.0 Hz, the crystallization quality changes from 0.4897g to 0.3523g at 10s. The faster crystallization rate can be obtained under the low frequency and the high power, but the crystallization yield is reduced. It is because the increased dissolved quantity mainly disperses by the finely groundparticles form in the solution.3. The effects of ultrasound on surface morphologyThe cupric sulfate crystal microscopic morphology and the structure are investigated using the scanning electronic microscope. It is found that: When the other conditions is the same, with the ultrasonic power increased, the crystallization of the product particles become smaller and uniform distribution. When the other conditions is the same, the crystallization of the product particles are smaller and uniform distribution at the low-ultrasonic-frequency. In order to obtain the small and unform distribution partics, the low-frequency, high power ultrasonic should be used.