Na2CO3-NaF-H2O三元水盐体系在313.15K和343.15K相平衡研究  

Study on phase equilibrium for ternary system Na2CO3 -NaF-H2Oat 313.15 K and 343.15 K

作　　者：郝晴 李梅[2,3] 黄兰[2,3] 刘兴宇 张雨涵 HAO Qing;LI Mei;HUANG Lan;LIU Xing-yu;ZHANG Yu-han(Institute of Mining Research,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China;Key Laboratory of Green Extraction and Efficient Utilization of Light Rare Earth Resources,Ministry of Education,Baotou 014010,Inner Mongolia,China;Institute of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China)

机构地区：[1]内蒙古科技大学矿业研究院,内蒙古包头014010 [2]内蒙古自治区轻稀土资源绿色提取与高效利用教育部重点实验室,内蒙古包头014010 [3]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《化学工程》2020年第6期57-62,共6页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(51564042);内蒙古自然科学基金重大项目(2014ZD04);内蒙古自治区自然科学基金重大项目(2016ZD05)。

摘　　要：在氟化钠的制备和稀土提取的工艺中都会产生富含氟化钠和碳酸钠的废水,对NaF-Na 2 CO 3-H 2 O三元体系的研究既为氟化钠碳酸钠的分离提供理论指导,也为四元体系研究奠定基础。文中采用等温溶解平衡法研究了313.15 K和343.15 K下NaF-Na 2 CO 3-H 2 O体系的相平衡关系,并测定了体系平衡时各组分的溶解度和平衡液相密度,根据实验数据绘制了相图,结果表明:在313.15 K和343.15 K时该体系均包含5个结晶区,3条单变量曲线,1个共饱和点,平衡固相均为Na 2 CO 3·H 2 O和NaF的混合物。饱和液体密度随含盐量的增加而增大,最大密度出现在共饱和点,碳酸钠对氟化钠有盐析作用。313.15 K和343.15 K平衡相图基本一致,位置无明显变化,证明该体系受温度影响较小,这对预测其他温度时该体系的平衡相图趋势有一定帮助。In the process of rare earth extraction and NaF preparation,wastewater rich in NaF and Na 2 CO 3 was produced.The research on the ternary system of NaF-Na 2 CO 3-H 2 O not only provides theoretical guidance for separation of NaF and Na 2 CO 3 but also lay the foundation for research of quaternary system.The stable phase equilibrium of the ternary system NaF-Na 2 CO 3-H 2 O at 313.15 K and 343.15 K was studied by isothermal dissolution equilibrium method.The solubilities and densities indices of the equilibrium solution were determined.Based on the experimental data,the stable phase diagram was plotted.The results show that the phase diagram involves five crystalline regions,three univariant curves,and one invariant point.The equilibrium solid phase is a mixture of Na 2 CO 3·H 2 O and NaF.The density of the saturated liquid increases with the salt content increases,and the maximum density occurs at the invariant point.Na 2 CO 3 has a salting out effect on NaF.The equilibrium phase diagrams of 313.15 K and 343.15 K are basically the same,and there is no obvious change in position.It proves that the system is less affected by temperature,which is helpful to predict the trend of equilibrium phase diagrams of the system at other temperatures.

关 键 词：碳酸钠 氟化钠 固液平衡 溶解度 

分 类 号：O611.65[理学—无机化学]