( 1. 中国铝业公司郑州轻金属研究院，郑州450041；
2. 中南大学 化学化工学院，长沙 410083)
摘 要: 铝酸钠溶液声致自由基的测定对超声强化铝酸钠溶液种分过程反应机理的探讨起着十分重要的作用。以DMPO(5, 5-dimethyl-1-pyrroline-N-oxide) 作为自旋捕获剂，应用自旋捕获技术与电子自旋共振（ESR）波谱连用的方法检测到铝酸钠溶液在超声空化作用下产生·OH自由基，讨论了声致自由基的产生与超声作用时间及铝酸钠溶液浓度的关系。结果发现，只有在超声波处理浓度较低的铝酸钠溶液时，才可能产生·OH自由基，且随着超声作用时间的延长，自由基的产量也随之增加，但当超声作用时间超过10 min时，自由基含量基本不随作用时间的延长而改变。
关键字: 铝酸钠溶液； ·OH自由基； 超声； 电子自旋共振
in sodium aluminate liquor
（ 1. Zhengzhou Light Metal Research Institute China Aluminium Corporation,
Zhengzhou 450041, China;
2. College of Chemistry and Chemical Engineering, Central South University,
Changsha 410083, China）
Abstract: In order to probe the mechanism of ultrasonic intensification on gibbsite precipitation process from sodium aluminate liquor, the ultrasonic induced hydroxyl free radicals was detected by electron spin resonance(ESR) spectroscopy using DMPO (5, 5-dimethyl-1-pyrroline-N-oxide) as a spin trap. The relationship of ultrasonic induced ·OH free radical with ultrasonic processing time and the concentration of sodium aluminate liquor were discussed. The results show that ·OH free radicals can be only produced in relative diluted sodium aluminate liquor. With the processing time prolonging, the yield of ultrasonic induced ·OH free radical increases, but the yield does not change when the processing time is longer than 10 min.
Key words: sodium aluminate liquor; ·OH free radicals; ultrasound; electron spin resonance
