盐湖卤水锂萃取体系的性能研究

采用溶剂萃取法从盐湖卤水中提取锂,筛选出萃取剂为TBP,协萃剂为MIBK,共萃剂为FeCl_3,稀释剂为磺化煤油。优化萃取条件如下:40%TBP+20%MIBK+40%磺化煤油、O/A=2.5、n(Fe~(3+)/Li~+)=2.5、初始水相H+0.04mol/L。结果表明,单级锂萃取率为91.21%,镁萃取率为2.10%,锂镁分离系数为483.05。经化学法、红外吸收光谱法证实了新萃合物的生成,并通过斜率法初步推断其组成为LiFeCl_4·4TBP·MIBK。根据离子缔合萃取理论讨论了萃取过程,证实了该混合体系适合从高Mg/Li、低酸度的氯化物型盐湖中萃取锂。

Study on Properties of Lithium Solvent Extraction System for Salt Lake Brine

Lithium was extracted from salt lake brine with mixed solvent system consisting of extraction agent of TBP, synergistic solvent extraction agent of MIBK, co-extraction agent of FeCl3, and diluent of sulfonated kerosene. The optimum solvent extraction conditions include 40%TBP 20%MIBK 40% sulfonated kerosene, O/A=2.5, n(Fe3 /Li )=2.5, and original H concentration of 0.04 mol/L. The results show that single-stage lithium solvent extraction rate is 91.21%, and magnesium solvent extraction rate is 2.10% with separation coefficient ( ) of 483.05. New extracting complex formation is demonstrated by chemical analysis and IR spectra, and the formation is LiFeCl4?4TBP?MIBK inferred by slope method. Extraction processes are discussed based on ion-pair extraction theory. This mixed system is demonstrated to extract lithium from chloride salt lake with high Mg/Li ratio and low acidity.