摘要
针对含锂相关水盐体系相平衡研究不够完善的问题,采用等温溶解平衡法研究四元体系Li^+,Mg^(2+)//SO_4^(2-),B_4O_7^(2-)-H_2O在273 K相平衡关系,并根据溶解度数据绘制相图。结果表明该体系属于简单交互四元体系,无复盐和固溶体生成。其相图包含2个共饱点,5条单变量曲线和4个结晶相区(分别是Li_2B_4O_7·3H_2O、Li_2SO_4·H_2O、MgB_4O_7·9H_2O和MgSO_4·7H_2O)。从相图中可以看出,MgB_4O_7所对应的相区最大,溶解度最小。对比该体系在不同温度下相图发现,随着温度升高MgSO_4和MgB_4O_7的结晶区明显减小,而Li_2B_4O_7和Li_2SO_4的结晶区明显增大,说明MgSO_4和MgB_4O_7的溶解度相较于Li_2B_4O_7和Li_2SO_4对温度变化更敏感。
Phase equilibrium of water-salt systems containing lithium is not well studied.An isothermal dissolution equilibrium method was used to study phase equilibrium of Li+,Mg2+//SO42-,B4O72--H2Oquaternary system at 273K,and phase diagram was obtained.The results show that this quaternary system is a simple interactive quaternary system without double salt or solid solution formation.The phase diagramcontains two invariant points,five univariant curves and four crystallization areas(corresponding to Li2B4O7·3H2O,Li2SO4·H2O,MgB4O7·9H2O and MgSO4·7H2O).The phase diagram shows that MgB4O7has thelargest phase region and the lowest solubility.Phase diagrams at different temperatures were compared and theresults show that with the increase of temperature,the crystallization regions of MgSO4 and MgB4O7decreasesignificantly,while the crystallization regions of Li2B4O7and Li2SO4increase significantly.The results showthat the solubility of MgSO4and MgB4O7is more sensitive to temperature than that of Li2B4O7 and Li2SO4.
作者
徐靖舒
张雯瑶
桑世华
XU Jing-shu;ZHANG Wen-yao;SANG Shi-hua(College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology,Chengdu 610059, China;Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions,Chengdu 610059, China)
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2018年第6期1458-1464,共7页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(41373062
U1407108)
四川省教育厅高校科研创新团队(15TD0009)
关键词
溶解度
干盐相图
硼酸盐
硫酸盐
solubility
dry-salt phase diagram
borate
sulfate
