超声波作用下溶剂萃取法分离镧铈元素

摘要

Aiming at the excess ammonia discharge caused by methods of solvent extraction and separation of rare earth elements using ammonia or sodium hydroxide as the saponification agent,this paper investigated the method of using ultrasonic unsaponifiable P204 to extract and separate the lanthanum and cerium elements. This paper examined the effects of the acidity of the feed liquid,the ultrasonic intensity,the ultrasonic intensity on the distribution ratio of lanthanum and cerium,the separation factor of lanthanum and cerium and the saturation extraction capacity respectively. The results showed that when the feed acidity was 5,ultrasonic intensity was at 20 W/cm2,ultrasonic frequency was at 30 kHz,the distribution ratio of lanthanum and cerium,the saturation extraction capacity of lanthanum and cerium and the separation factor between lanthanum and cerium reached the maximum. The saturation extraction capacity were 35 g/L and 19 g/L,and the maximum separation factor between the lanthanum and the cerium was 4.63. The results under infrared spectroscopy showed that ultrasound caused hydrogen bond break in P204 in the solvent extraction and separation of lanthanum and cerium,resulting in, more monomer P204 react with rare earth in the extraction process. Therefore,the saturation extraction capacity of lanthanum and cerium with ultrasonic was greater than that without ultrasonic.%针对溶剂萃取法分离稀土元素的工艺中采用氨水为皂化剂造成排放的废水中氨氮含量超标，采用氢氧化钠为皂化剂使得排放废水中钠盐含量超标而造成环境污染的问题，研究了以未皂化的P204为萃取剂，超声波作用下镧铈元素萃取分离的方法。考察了料液酸度、超声波强度、超声波频率分别对镧铈分配比、分离系数及饱和萃取容量的影响。结果表明：当超声波强度为20 W/cm2、超声波频率为30 kHz、料液酸度为5时，镧铈元素的分配比、饱和萃取容量和元素间的分离系数达到最大，其中饱和萃取容量分别为35 g/L和19 g/L，镧铈间的分离系数最大为4.63。通过红外光谱检测可知溶剂萃取法分离镧铈元素时，由于超声波的作用使得萃取剂 P204二聚体中的氢键部分断裂，因此有更多的单体P204能够与稀土离子发生萃取反应，所以超声波作用下镧铈的饱和萃取容量和分配比均大于无超声波作用。