中文摘要：

利用自制实验装置考察了功率超声对磷酸铵镁（MAP）溶液的结晶介稳区、诱导期、结晶反应速率和晶型等结晶反应特性的影响作用规律。结果表明,对于浓度为4 mmol/L的MAP溶液,分别施加150、250和350 W的功率超声,其达到超饱和状态的临界pH值分别比自然反应条件的临界pH值降低0.14、0.21和0.38,结晶介稳区也随超声功率的增加逐渐变窄;施加150-200 W的功率超声,可将MAP的结晶诱导期从340 s缩短至50-100 s以下,但是继续提高超声功率,结晶诱导期变化不大;超声作用下的MAP结晶反应速率明显加快,随着超声功率的增加,结晶反应速率曲线的缓慢平台期几近消失;扫描电镜观测结果表明,超声作用下MAP结晶产物更加均匀,晶体形貌完整,晶体增长较快。

英文摘要：

A specialized experimental device was utilized to investigate the influence of ultrasound on the crystallization characteristics of magnesium ammonium phosphate（ MAP）; the crystallization metastable zone width,induction period,reaction rate,and the crystal shape of MAP were analyzed in detail. The results showed that the critical pH value of the supersaturated MAP solution would decrease by 0. 14,0. 21,and 0. 38 with ultrasonication of 4 mmol / L MAP reaction solutions at 150,250,and 350 W,respectively. Moreover,the metastable zone width gradually narrowed with increasing ultrasonic power,and the induction period of MAP solutions could be shortened from 340 s to the range from 50 to 100 s while increasing the ultrasound power to the range from 150 to 200 W. However,there was a slight change in the induction period as the increase in ultrasonic power continued. It was also observed that the crystallization reaction rate of MAP could be accelerated significantly by ultrasonication,and the plateaus of the MAP crystallization reaction rate curve nearly vanished as the ultrasonic power increased. Furthermore,more uniform,more complete,and fast growth of the produced MAP crystal as the ultrasound power increased was observed from scanning electron microscopy（ SEM） images.