三元体系Li^+、Mg^(2+)//borate–H_2O 288.15,K固液相平衡研究  

Solid-liquid Phase Equilibria in the Ternary System Li^+,Mg^(2+)//borate-H_2O at 288.15,K

作　　者：景妍[1] 王士强[2,3] 胡海清[2] 赵美玲[1] 韩徐年 郭亚飞[2,3] 邓天龙[2,3] 

机构地区：[1]天津科技大学海洋与环境学院,天津300457 [2]天津科技大学化工与材料学院,天津300457 [3]天津市海洋资源与化学重点实验室,天津300457

出　　处：《天津科技大学学报》2016年第4期40-44,共5页Journal of Tianjin University of Science & Technology

基　　金：国家自然科学基金资助项目(21276194,U1507109);天津市应用基础与前沿技术研究计划项目(12JCQNJC03400)

摘　　要：采用等温溶解法研究三元体系Li+、Mg2+//borate–H2O在288.15,K时稳定相平衡,并测定其溶解度及物化性质(密度、折光率和p H),根据实验数据绘制稳定相图及物化性质–组成图.结果表明:该三元体系为水合物I型,无复盐及固溶体形成;相图中有1个共饱点E(Li2B4O7·3H2O+Mg2B6O11·15H2O),对应的液相组成(质量分数)为:Li2B4O72.88%、Mg B4O7 0.02%,2条单变量曲线AE和BE,2个单盐结晶区,对应的平衡固相为Li2B4O7·3H2O和Mg2B6O11·15H2O;随着Li2B4O7的含量增大,Mg B4O7的含量减小,表明Li2B4O7对Mg B4O7存在一定的盐析效应.研究发现:章氏硼镁石在该体系288.15,K时不能够稳定存在,极易与水反应转化为更为稳定的多水硼镁石.稳定平衡液相的密度、折光率、p H均随着液相中Li2B4O7浓度的变化呈有规律的变化.其中,密度和折光率随着Li2B4O7浓度的增大而增大,到共饱点处达到最大值,采用经验公式拟合密度和折光率,拟合值与实验值吻合得较好.The phase equilibrium of the ternary system Li＋,Mg2＋//borate-H2O has been researched at 288.15,K using aniso-thermal dissolution method.The solubility and physico-chemical properties such as density,refractive index and pHvalue were analyzed.Based on the experimental data,the phase diagram at 288.15,K and diagrams of physico-chemicalproperties versus compositions were plotted respectively.The results showed that the ternary system at 288.15,K belongs tohydrate Ⅰ type and no double salt or solid solution was generated.There was one eutectic point（liquid phase compositionis Li2B4O7 2.88%, ,MgB4O7 0.02%,） ;two univariate curves and two crystallization fields（Li2B4O7·3H2O andMg2B6O11·15H2O）.The concentration of MgB4O7,decreased with the increase of the concentration of Li2B4O7,which showsthat Li2B4O7,has an salting-out effect on MgB4O7.It was found that MgB4O7·9H2O is unstable at 288.15,K;it easily reactswith water and then converts into Mg2B6O11·15H2O.Physico-chemical properties changed regularly with the increase ofLi2B4O7 content.Density and refractive index increased with the increase of the concentration of Li2B4O7,and reached thehighest at the eutectic point,then decreased.The values calculated with empirical equations highly matched the experimentalvalues.

关 键 词：稳定相平衡 溶解度 锂硼酸盐 镁硼酸盐 

分 类 号：TQ131.1[化学工程—无机化工]