CIESC Journal ›› 2018, Vol. 69 ›› Issue (7): 2829-2837.DOI: 10.11949/j.issn.0438-1157.20171695

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Solubility determination of calcium sulfate dihydrate in ammonium sulfate solution

GE Jing, ZHU Jiahua, XIA Sulan, LIU Shizhong   

  1. School of Chemical Engineering, Sichuan University, Chengdu 610065, Sichuan, China
  • Received:2017-12-28 Revised:2018-04-18 Online:2018-07-05 Published:2018-07-05
  • Supported by:

    supported by the National Natural Science Foundation of China(91434121).

二水硫酸钙在硫酸铵溶液中的溶解度测定

葛敬, 朱家骅, 夏素兰, 刘仕忠   

  1. 四川大学化学工程学院, 四川 成都 610065
  • 通讯作者: 朱家骅
  • 基金资助:

    国家自然科学基金项目(91434121)。

Abstract:

The effect of the concentration (0-2.5 mol·kg-1) of ammonium sulfate on the solubility of calcium sulfate dihydrate is measured in inductively coupled plasma-atomic emission spectrometry (ICP-AES) under the conditions of 298.15-348.15 K. The activity coefficient model of extended Debye-Hückel was applied to correlate the experimental data, and the averaged relative deviation were found at 2.81%. Meanwhile, the activity coefficient model of extended UNIQUAC-Debye-Hückel was applied to calculate the solubility of calcium sulfate dihydrate in ammonium sulfate solution, and the experimental data agreed well with the model prediction, with an averaged relative deviation of 4.13%. The theoretical and experimental results show that the solubility of calcium sulfate dihydrate can firstly decrease and then increase with the increasing of the concentration of ammonium sulfate under the conditions of 298.15-348.15 K. At the solubility mutation point the concentration of ammonium sulfate is 0.07-0.08 mol·kg-1 under the synergetic effect of common-ion effect and salt effect. There are strong effects of temperature on the solubility of calcium sulfate dihydrate under higher ammonium sulfate concentrations (0.3-2.5 mol·kg-1). The results provide better understanding and theoretical guidance for process design of CO2 mineralization with phosphogypsum.

Key words: calcium sulfate dihydrate, ammonium sulfate, solubility, extended Debye-Hückel model, extended UNIQUAC-Debye-Hückel model, CO2 mineralization

摘要:

采用电感耦合等离子体发射光谱法(ICP-AES)测定了二水硫酸钙在硫酸铵溶液中(298.15~348.15 K)的溶解度,利用E-DH方程对实验数据进行关联,总平均相对偏差为2.81%;并考察了E-UDH方程的理论预测值,与实验值对比,总平均相对偏差为4.13%。实验和理论研究结果表明:在同离子效应和盐效应协同影响下,二水硫酸钙在(NH42SO4-H2O体系中溶解度随硫酸铵浓度增加先降低后又增大,在298.15~348.15 K温区内,溶解度突变点硫酸铵浓度为0.07~0.08 mol·kg-1;随溶液中硫酸铵浓度增加,温度对二水硫酸钙溶解度的影响更趋显著。研究结果对磷石膏矿化烟气CO2的过程设计具有指导意义。

关键词: 二水硫酸钙, 硫酸铵, 溶解度, E-DH方程, E-UDH方程, CO2矿化

CLC Number: