氯化镁熔盐水合物的电化学性质研究  

Study on electrochemical properties of magnesium chloride molten salt hydrates

作　　者：董明哲 李可昕 叶秀深[1,2] 马珍 李生廷 李权 吴志坚[1,2] DONG Mingzhe;LI Kexin;YE Xiushen;MA Zhen;LI Shengting;LI Quan;WU Zhijian(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt-lake Resources,Qinghai Institute of Salt-lakes,Chinese Academy of Sciences,Xining 810008,China;Key Laboratory of Salt-lake Resources Chemistry of Qinghai Province,Xining 810008,China;Qinghai Salt Lake Industry Co.,Ltd.,Golmud 816000,China;University of Chinese Academy of Sciences,Beijing 100049 China)

机构地区：[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]青海盐湖工业股份有限公司,青海格尔木816000 [4]中国科学院大学,北京100049

出　　处：《无机盐工业》2024年第2期51-56,共6页Inorganic Chemicals Industry

基　　金：国家自然科学基金项目(U21A20323,U20A20147);青海盐湖工业股份有限公司科技计划项目(E141GH01);青海省中青年科技人才托举工程项目(2021QHSKXRCTJ29)。

摘　　要：熔盐水合物一般是指水盐物质的量比小于或等于阳离子水合数或配位数的无机盐熔体,对其性质进行研究有助于深入了解无机盐结晶水合物的脱水过程和脱水机理。测定了不同组成的MgCl_(2)-H_(2)O体系以液态存在的最低温度及其在不同温度下的电导率,并采用循环伏安法研究了MgCl_(2)-H_(2)O体系和MgCl_(2)-KCl-H_(2)O体系的电化学性质。结果表明:在相同温度下,MgCl_(2)-H_(2)O体系稀溶液的电导率随着含水量的降低先增大后逐渐减小,当含水量相同时,MgCl_(2)-H_(2)O体系电导率随着温度的升高逐渐增大;在浓溶液和熔盐水合物中,相同温度下电导率随着含水量的降低逐渐减小;对于MgCl_(2)-H_(2)O体系,当达到氧化或还原电位时,阳极和阴极电流均随着含水量的增加而明显增大;在MgCl_(2)熔盐水合物中加入KCl后,熔盐水合物体系中Cl-浓度增大,Cl-置换了水合镁离子中的部分水分子,使氢的还原更加容易;在MgCl_(2)·6H_(2)O脱水过程中,Cl-的加入可以抑制MgCl_(2)·6H_(2)O水解反应的发生,从而更有利于MgCl_(2)·6H_(2)O的脱水。Molten salt hydrates(MSHs)are inorganic salt melts in general,in which the molar ratio of water-to-salt is less than or equal to the hydration number or coordination number of the cation.To comprehend the dehydration procedure and mechanism of inorganic salt hydrates thoroughly,it is essential to study their characteristics.The conductivity of the MgCl_(2)-H_(2)O system at various temperatures was measured,as well as the lowest temperature at which the system with different compositions existed in liquid form.By employing the cyclic voltammetry technique,the electrochemical characteristics of the MgCl_(2)-H_(2)O and MgCl_(2)-KCl-H_(2)O systems were comprehensively investigated.The conductivity was increased initially and then was steadily decreased when the water content of the MgCl_(2)-H_(2)O system was decreased at the same temperature.The conductivity was gradually increased when the temperature was increased at the same water content in dilute solution.The conductivity was decreased with the decrease of water content in concentrated solutions or MSHs at the same temperature;The anodic and cathodic currents in the MgCl_(2)-H_(2)O system were dramatically increased with increasing water content after reaching the oxidation or reduction potential in cyclic voltammetry tests.The concentration of Cl-in the molten salt hydrate system was increased after adding KCl,and Cl-replaced some water molecules in the hydrated magnesium ions,making hy-drogen reduction easier.In the dehydration of MgCl_(2)·6H_(2)O,the addition of Cl-could decrease the hydrolysis reaction of MgCl_(2)·6H_(2)O,making it more conducive to dehydration of MgCl_(2)·6H_(2)O.

关 键 词：氯化镁 熔盐水合物 电导率 循环伏安实验 

分 类 号：O646[理学—物理化学]