碳酸锂在氯化钠溶液中溶解度的测定  

Solubility determination of lithium carbonate in sodium chloride solution

作　　者：戈海文[1,2] 王怀有 王敏[1,2] GE Hai-wen;WANG Huai-you;WANG Min(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)

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

出　　处：《高校化学工程学报》2020年第4期855-862,共8页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(U1507202)。

摘　　要：采用等温溶解平衡法测定了在温度为278.15~358.15 K时,Li2CO3在质量摩尔浓度为0~4.06 mol·kg^-1 NaCl溶液中的溶解度和溶液密度,利用E-DH和Apelblat方程对Li2CO3溶解度实验数据进行关联,计算相对偏差在±0.05以内;利用Connaughton方程对液相密度数据进行关联,标准偏差小于7×10^-4。实验和理论计算结果表明:Li2CO3在NaCl-H2O体系中溶解度随NaCl浓度增加先增大后又减小,在温度278.15~358.15 K内,溶解度在NaCl质量摩尔浓度约为1 mol·kg^-1时出现最大值。通过溶解热力学计算,得到Li2CO3在NaCl中的溶解焓变ΔHd、熵变ΔSd和吉布斯自由能变ΔGd,结果表明溶解过程为放热、熵减的非自发过程,溶解焓变和熵变随着NaCl浓度变大而增加,吉布斯自由能变ΔGd在NaCl质量摩尔浓度为1 mol·kg^-1出现最小值,且溶解过程为熵控制过程。研究结果将为卤水提锂碳化沉锂过程设计提供基础数据。The solubility and solution density of Li2CO3 in NaCl solution at the molalities of(0~4.06)mol·kg^-1 were determined by an isothermal dissolution equilibrium method at 278.15~358.15 K.The experimental data of lithium carbonate solubility was correlated by E-DH and Apelblat equations,with relative deviation of±0.05.The Connaughton equation was used to correlate the solution density data with a standard deviation of less than 7×10^-4.The experimental and theoretical calculations show that the solubility of Li2CO3 in NaCl-H2O system increases first and then decreases with the increase of NaCl concentration.In the temperature range of 278.15~358.15 K,the maximum solubility of Li2CO3 is obtained at NaCl concentration of^0.1 mol×kg^-1.The dissolution enthalpyΔHd,entropyΔSd and Gibbs free energyΔGd of Li2CO3 in aqueous NaCl solution were obtained by dissolution thermodynamic calculation.The results show that the dissolution process is a non-spontaneous process of exotherm and entropy reduction.The dissolution enthalpy and entropy increase with the increase of sodium carbonate concentration.Gibbs free energy shows minimum at 1 mol×kg^-1,and the dissolution process is an entropy controlled process.The research results provide basic data for the design of lithium carbide precipitation process for brine.

关 键 词：碳酸锂 氯化钠 溶解度 关联模型 热力学计算 

分 类 号：O645.12[理学—物理化学]