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 ›› 2024, Vol. 56 ›› Issue (1): 47-52.doi: 10.19964/j.issn.1006-4990.2023-0074

• 研究与开发 • 上一篇    下一篇

三元体系Na+(Mg2+),Ca2+∥Cl--H2O 278.2 K稳定相平衡研究

冯霞1(), 于雪峰2, 姚智豪1, 罗军1,2, 任思颖1,2, 赵志星1, 于旭东1()   

  1. 1.成都理工大学材料与化学化工学院,四川 成都 610059
    2.青海盐湖工业股份有限公司,青海格尔木 816099
  • 收稿日期:2023-02-15 出版日期:2024-01-10 发布日期:2024-01-18
  • 通讯作者: 于旭东(1985— ),男,博士,副教授,研究方向为相平衡与分离技术;E-mail: xwdlyxd@126.com
  • 作者简介:冯霞(1999— ),女,硕士,研究方向为相平衡与相图;E-mail: fengxiac413@126.com
  • 基金资助:
    四川省科技计划资助项目(2022YFQ0075);油气藏地质及开发工程国家重点实验室项目(PLC20210502)

Study on phase equilibria of aqueous ternary system of Na+(Mg2+),Ca2+∥Cl--H2O at 278.2 K

FENG Xia1(), YU Xuefeng2, YAO Zhihao1, LUO Jun1,2, REN Siying1,2, ZHAO Zhixing1, YU Xudong1()   

  1. 1. College of Materials and Chemistry & Chemical Engineering,Chengdu University of Technology,Chengdu 610059,China
    2. Qinghai Salt Lake Industry Co.,Ltd.,Golmud 816099,China
  • Received:2023-02-15 Published:2024-01-10 Online:2024-01-18

摘要:

含钠镁钙水盐体系的多温相平衡研究,可为含钙镁盐湖资源的持续开发提供数据支撑。因此,采用等温溶解法开展了两个三元体系Na+,Ca2+∥Cl--H2O和Mg2+,Ca2+∥Cl--H2O在278.2 K下的相平衡研究,测定了溶解度、折射率和密度,并绘制了相应的相图。结果表明,三元体系Na+,Ca2+∥Cl--H2O和Mg2+,Ca2+∥Cl--H2O在278.2 K时均为简单体系,无复盐或固溶体生成。三元体系Na+,Ca2+∥Cl--H2O在278.2 K时的氯化钠结晶区远大于氯化钙,对比该体系273.2、278.2、298.2、348.2 K多温相图可知,随温度升高,氯化钠结晶区增大,氯化钙结晶形式由CaCl2·6H2O转变为CaCl2·2H2O。三元体系Mg2+,Ca2+∥Cl--H2O在278.2 K时的MgCl2·6H2O结晶区大于CaCl2·6H2O,对比该体系273.2、278.2、303.2、308.2、348.2、383.2 K多温相图发现:303.2、308.2、348.2、383.2 K时体系中形成复盐2MgCl2·CaCl2·12H2O,且其结晶区随温度升高而增大;383.2 K时体系中同时存在两种复盐2MgCl2·CaCl2·12H2O和MgCl2·2CaCl2·6H2O。

关键词: 相平衡, 相图, 溶解度, 水合盐

Abstract:

Study on the multitemperature phase equilibria of water-salt system containing sodium,magnesium and calcium can provide data support for the sustainable development of salt lakes containing magnesium and calcium.Therefore,the phase equilibria of two aqueous ternary system of Na+,Ca2+∥Cl--H2O and Mg2+,Ca2+∥Cl--H2O at 278.2 K were investigated by the isothermal dissolution method,the solubility,refractive index and density of these two systems were determined,the corresponding phase diagrams were constructed based on the experimental data.The results showed that Na+,Ca2+∥Cl--H2O and Mg2+,Ca2+∥Cl--H2O were both belong to simple system without double salts or solid solution formed at 278.2 K.The crystallization regions of NaCl was much larger than CaCl2·6H2O in the system Na+,Ca2+∥Cl--H2O at 278.2 K,comparing the phase diagrams of the system at 273.2,278.2,298.2,348.2 K,it could be seen that with the increase of temperature,the crystallization area of NaCl was increased,and the crystal form of CaCl2 was changed from CaCl2·6H2O to CaCl2·2H2O.The crystallization region of MgCl2·6H2O was larger than CaCl2·6H2O in the system Mg2+,Ca2+∥Cl--H2O at 278.2 K,comparing the phase diagrams of the system at 273.2,278.2,303.2,308.2,348.2,383.2 K,it was found that the double salt tachyhydrite 2MgCl2·CaCl2·12H2O was formed at 303.2,308.2,348.2,383.2 K,and its crystallization region was increased with the increase of temperature.There were two double salts of 2CaCl2·MgCl2·6H2O and 2MgCl2·CaCl2·12H2O formed at 383.2 K.

Key words: phase equilibria, phase diagram, solubility, hydrate salt

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