CIESC Journal ›› 2021, Vol. 72 ›› Issue (6): 3130-3139.DOI: 10.11949/0438-1157.20201594

• Special column for comprehensive utilization of salt lake resouces in Qinghai • Previous Articles     Next Articles

Study on separation of magnesium and lithium from salt lake brine with high magnesium-to-lithium mass ratio by nanofiltration membrane

LI Yan1,2,3(),WANG Min1,2(),ZHAO Youjing1,2,WANG Huaiyou1,2,YANG Hongjun1,2,ZHU Zenghu1,2   

  1. 1.Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai, China
    2.Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Xining 810008, Qinghai, China
    3.University of Chinese Academy of Sciences, Beijing 101408, China
  • Received:2020-11-03 Revised:2020-12-18 Online:2021-06-05 Published:2021-06-05
  • Contact: WANG Min

纳滤膜对高镁锂比盐湖卤水镁锂分离性能研究

李燕1,2,3(),王敏1,2(),赵有璟1,2,王怀有1,2,杨红军1,2,祝增虎1,2   

  1. 1.中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海 西宁 810008
    2.青海省盐湖资源化学重点实验室,青海 西宁 810008
    3.中国科学院大学,北京 101408
  • 通讯作者: 王敏
  • 作者简介:李燕(1992—),女,博士研究生,liyan615@mails.ucas.edu.cn
  • 基金资助:
    青海省重大科技专项(2019-GX-A7);国家重点研发计划项目(2018YFC0604804)

Abstract:

As an emerging membrane separation technology, nanofiltration has a potential application in separating magnesium and lithium from salt lake brine with a high magnesium-to-lithium mass ratio (Mg/Li). The separation of magnesium and lithium at different Mg/Li and cross-flow rates was evaluated and analysis on the mechanism in separation process was performed. The results showed that the membrane flux remained almost constant at different Mg/Li, the retention rates of magnesium and lithium and the separation efficiency decreased with increasing Mg/Li. When the cross-flow rate was 225 L/h, the retention rates of magnesium and lithium were 95% and -66%, respectively. In addition the Mg/Li in the permeate was reduced to 1.2. Study on the mechanism of mass transport for membrane process showed that magnesium was greatly influenced by dielectric exclusion, and steric hindrance. Nanofiltration shows considerable promise as a means to separate magnesium and lithium from salt lake brine with high magnesium-to-lithium mass ratios, which provides the basis for the subsequent preparation of high-purity lithium salt.

Key words: membrane, nanofiltration, salt lake brine, separation, Mg/Li, cross-flow rate

摘要:

纳滤作为一种新兴的膜分离技术,在高镁锂比盐湖卤水镁、锂分离领域具有非常好的应用前景。研究了不同镁锂比、原料液循环流量对镁锂分离过程的影响,并对膜分离过程中的分离机理进行分析。结果表明原料液镁锂比对膜通量影响较小,镁、锂离子截留率及镁锂分离效果均随原料液镁锂比的增加而降低。当原料液循环流量为225 L/h时,镁离子截留率为95%,锂离子截留率为-66%,透过液镁锂比降低至1.2。膜分离传质机理研究表明,镁离子在分离过程中受到较强的介电排斥效应与尺寸筛分效应。纳滤技术能够有效降低高镁锂比盐湖卤水的镁锂比,为后续高纯锂盐的制备提供基础。

关键词: 膜, 纳滤, 盐湖卤水, 分离, 镁锂比, 循环流量

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