高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (1): 55.doi: 10.7503/cjcu20120171

• 研究论文: 无机化学 • 上一篇    下一篇

共萃剂ClO4- 作用下磷酸三丁酯分离盐湖卤水锂镁

杨立新, 邬赛祥, 刘肖丽, 何靖, 陈文光   

  1. 湘潭大学化学学院, 环境友好化学与应用省部共建教育部重点实验室, 湘潭 411105
  • 收稿日期:2012-03-01 发布日期:2012-12-31
  • 通讯作者: 杨立新,男,教授,主要从事资源与环境友好化学研究.E-mail:ylx@xtu.edu.cn E-mail:ylx@xtu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 21276215)和湖南省研究生科研创新项目(批准号: CX2010B267)资助.

Lithium and Magnesium Separation from Salt Lake Brine by Tributyl Phosphate under Action of Co-extraction Reagent ClO4-

YANG Li-Xin, WU Sai-Xiang, LIU Xiao-Li, HE Jing, CHEN Wen-Guang   

  1. Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
  • Received:2012-03-01 Published:2012-12-31

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摘要：

采用磷酸三丁酯(TBP)作为萃取剂, NaClO4作为共萃剂从高镁锂比盐湖卤水中提取锂, 考察了萃取温度、 溶液pH值、 相比和ClO4-用量等因素对Li+萃取率的影响. 结果表明, 卤水一次萃取的最佳操作条件为: 萃取时间10 min, 温度25℃, Vo/Vw=2.0, n(ClO4-)/n(Li+)=2.0, pH=5~8, Li+和Mg2+的最高萃取率分别为65.41%和13.31%, 锂镁分离系数达到12.32. 用水在Vw/Vo=1.0、 50℃时进行反相萃取, Li+的反萃率达到81.52%, 此时镁锂质量比由45.61下降至8.45. 锂镁离子萃取过程呈放热效应, 金属离子的萃入对TBP中H的化学位移没有影响, 但会导致PO双键的红外伸缩振动吸收峰从1280 cm-1移至1264 cm-1. 25℃时用斜率法测定Li+萃合物的组成接近2LiClO4·5TBP, 反萃液经深度除镁后可制备碳酸锂.

关键词: ClO4-, 磷酸三丁酯, 高镁卤水, 锂镁分离, 溶剂萃取

Abstract:

Aiming at salt lake brine with a high ratio of magnesium/lithium, extracting lithium was researched via the extractant tributyl phosphate(TBP) as well as the co-extraction reagent NaClO4, and the effects of temperature, solution pH value, phase ratio, ClO4- amount and other factors on Li+ extraction rate have been investigated in detail. The optimum operating conditions of a single extraction from brine are the following: the extraction time of 10 min, temperature of 25℃, Vo/Vw=2.0, n(ClO4-)/n(Li+)=2.0 and pH value in a range of 5-8. Under these conditions, the highest extraction rate for Li+ and Mg2+ was 65.41% and 13.31%, respectively, and the Li/Mg separation coefficient reached 12.32. Reversed phase extraction was carried out with water in Vw/Vo=1.0 and 50℃, the stripping rate of Li+ reached 81.52%, and the mass ratio of Mg/Li decreased from 45.61 to 8.45. The extraction process of Li+ and Mg2+ presented exothermic effect, metal ions extracted into the organic phase had no effect on the chemical shifts of H in TBP, but made the IR stretching vibration frequencies of PO double bond shift to 1264 cm-1 from 1280 cm-1. The composition of extracted complex of Li+ was close to 2LiClO4·5TBP determined by the slope method at 25℃, and Li2CO3 was prepared by the strip liquor after demagnesium deeply.

Key words: ClO4-, Tributyl phosphate, Brine with high Mg content, Li/Mg separation, Solvent extraction

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