无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2023, Vol. 55 ›› Issue (2): 61-66.doi: 10.19964/j.issn.1006-4990.2022-0273

• 研究与开发 • 上一篇    下一篇

258.15 K下五元体系Li+,Na+,Mg2+//SO42-,Cl--H2O相平衡研究

闫芳宁(),郭锦春,黄雪莉(),周婷婷,王雪莹,罗清龙,邹雪净   

  1. 新疆大学化工学院,新疆煤炭清洁转化与化工过程自治区重点实验室,新疆 乌鲁木齐 830017
  • 收稿日期:2022-05-07 出版日期:2023-02-10 发布日期:2023-02-16
  • 通讯作者: 黄雪莉
  • 作者简介:闫芳宁(1996— ),女,硕士,主要研究方向为相平衡及应用研究;E-mail:1324648810@qq.com
  • 基金资助:
    国家自然科学基金(2176060169)

Study on phase equilibrium of quinary system of Li+,Na+,Mg2+//SO42-,Cl--H2O at 258.15 K

YAN Fangning(),GUO Jinchun,HUANG Xueli(),ZHOU Tingting,WANG Xueying,LUO Qinglong,ZOU Xuejing   

  1. College of Chemical Engineering,Xinjiang University,Key Laboratory of Cleaner Transition of Coal & Chemicals Engineering of Xinjiang Uyghur Autonomous Region,Urumqi 830017,China
  • Received:2022-05-07 Online:2023-02-10 Published:2023-02-16
  • Contact: HUANG Xueli

摘要:

中国含锂盐湖大部分位于青藏、新疆等干旱少雨、冬季寒冷且漫长的地区。为指导低温提锂工艺的开发和设计、利用冬季冷能进行目标离子的富集及明确含锂盐湖在低温下的析盐规律,采用等温溶解平衡法对258.15 K、二水氯化钠饱和条件下的交互五元体系Li+,Na+,Mg2+//SO42-,Cl--H2O相平衡关系进行研究并构建等温平衡相图。结果表明,相图中有4个共饱点、6个两盐结晶区(NaCl·2H2O+Na2SO4·10H2O、NaCl·2H2O+MgCl2·8H2O、NaCl·2H2O+MgSO4·7H2O、NaCl·2H2O+Li2SO4·H2O、NaCl·2H2O+LiCl·2H2O、NaCl·2H2O+LiCl·MgCl2·7H2O)、9条单变量溶解度曲线;6个结晶区中,只存在一种复盐为LiCl·MgCl2·7H2O,其结晶区最小,Na2SO4·10H2O结晶区最大。与该体系在273.15 K下的稳定相图相比,硫酸盐型复盐消失,复盐结晶区减少到1个,共饱点减少至4个,相图结构得以简化。因此,将涩聂湖卤水降温至258.15 K时能有效脱除硫酸根,从而实现富集锂离子的目的。

关键词: 盐湖, 锂, 低温, 五元体系, 相平衡

Abstract:

Most lithium salt lakes in China are located in areas with drought,little rain,cold and long winters,such as Qinghai Tibet and Xinjiang.To guide the process of lithium extraction at low temperature,enrich the target ions by using cold energy in winter and clarify the salt precipitation law of lithium-containing salt lake at low temperature,the phase equilibrium of the interactive quinary system of Li+,Na+,Mg2+//SO42-,Cl--H2O under saturated NaCl·2H2O at 258.15 K was investigated by isothermal dissolution method and the phase diagram was constructed.There were four invariant points,six two-salt crystallization fields(NaCl·2H2O+Na2SO4·10H2O,NaCl·2H2O+MgCl2·8H2O,NaCl·2H2O+MgSO4·7H2O,NaCl·2H2O+Li2SO4·H2O,NaCl·2H2O+LiCl·2H2O, NaCl·2H2O+LiCl·MgCl2·7H2O)and nine univariate solubility curves in the phase diagram.LiCl·MgCl2·7H2O was the only double salt in the phase diagram,and its crystallization field was the smallest.The crystallization field of Na2SO4·10H2O was the largest in the phase diagram.Compared with the stable phase diagram of the quinary system at 273.15 K,the sulfate type double salt was disappeared,the double salt crystallization zone was reduced to 1,and the invariant point was reduced to 4,and the correlation system was simplified.Cooling the brine of Seniehu lake to 258.15 K could effectively separate sulfate and achieve the purpose of enriching lithium.

Key words: salt lake, lithium, low temperature, quinary system, phase equilibrium

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