25℃下Mg2+,NH4+//Cl-,SO42--H2O四元体系等温蒸发介稳相平衡研究  

Solid-liquid metastable equilibria for isothermal evaporation of the quaternary system(Mg2+,NH4+//Cl-,SO42--H2O) at 25℃

作　　者：秦亚欠 赵斌[1] 赵晓玲 刘秀伍[1] 郭宏飞[1] 曹吉林[1] QIN Ya-qian;ZHAO Bin;ZHAO Xiao-ling;LIU Xiu-wu;GUO Hong-fei;CAO Ji-lin(Hebei Provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving,College of Chemical Engineering,Hebei University of Technology,Tianjin 300130,China)

机构地区：[1]河北省绿色化工与高效节能重点实验室河北工业大学化工学院

出　　处：《高校化学工程学报》2020年第1期17-26,共10页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21576066);河北省自然科学基金(B2017202268)

摘　　要：为了利用柴达木地区自然蒸发条件,提出介稳状态下氯化镁与硫酸铵为原料生产硫酸镁铵复肥的设想,采用等温蒸发法测定了25℃时Mg^2+,NH4^+//Cl^-,SO4^2--H2O体系及其三元子体系的介稳相平衡数据,并绘制了介稳相图。结果表明:(NH4)2SO4-MgSO4-H2O体系有2个共饱点,5个结晶区;MgCl2-MgSO4-H2O体系有3个共饱点,7个结晶区;Mg^2+,NH4^+//Cl^-,SO4^2--H2O四元体系存在6个共饱点和8个结晶区,分别为:MgSO4·(NH4)2SO4·6H2O结晶区,(NH4)2SO4结晶区,NH4Cl结晶区,MgCl2·NH4Cl·6H2O结晶区,MgSO4·7H2O结晶区,MgSO4·6H2O结晶区,MgSO4·5H2O和MgCl2·6H2O结晶区。Pitzer模型对实验数据进行了回归计算,计算值与实验值相吻合。确定了通过蒸发结晶生产硫酸镁铵复肥的工艺路线。In order to utilize the natural evaporation conditions in Qaidam area,a process using magnesium chloride and ammonium sulfate as raw materials to produce magnesium ammonium sulfate compound fertilizer was proposed.The metastable solubility of the Mg^2+,NH4^+//Cl^-,SO4^2--H2O system and its ternary systems at 25℃ were measured using the isothermal evaporation method,and the metastable phase diagrams were plotted.The metastable phase diagram of the ternary system(NH4)2SO4-MgSO4-H2O has two invariant points and five crystalline zones.The metastable phase diagram of the ternary system MgCl2-MgSO4-H2O has three invariant points and seven crystalline zones.In the metastable phase diagram of the quaternary system,there are six invariant points and eight crystalline zones that correspond to MgSO4·(NH4)2SO4·6H2O,(NH4)2SO4,NH4Cl,MgCl2·NH4Cl·6H2O,MgSO4·7H2O,MgSO4·6H2O,MgSO4·5H2O and MgCl2·6H2O.Based on the Pitzer model,correlation calculation results show that the calculated value is consistent with the experimental data.A technological process for the production of magnesium ammonium sulfate compound fertilizer by evaporation and crystallization is thus proposed.

关 键 词：溶解度 介稳相平衡 PITZER模型 硫酸镁铵 

分 类 号：O642.42[理学—物理化学]