Production of Potash and N-Mg Compound Fertilizer via Mineral Shoenite from Kunteyi Salt Lake:Phase Diagrams of Quaternary System(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O in the Isothermal Evaporation and Crystallization Process  

作　　者：LI Cheng CHEN Xueqing GUO Hongfei ZHOU Xue CAO Jilin 

机构地区：[1]Hebei Provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving,College of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China

出　　处：《Acta Geologica Sinica(English Edition)》2021年第3期1016-1023,共8页地质学报（英文版）

基　　金：This project was supported by the National Natural Science Foundation of China(grant No.21576066);the Natural Science Foundation of Hebei Province,China(No.B2017202268);the Research Fund Program of Guangdong Provincial Key Lab of Green Chemical Product Technology(No.GC201816).

摘　　要：Based on the requirement of the new technology for producing potassium sulfate and N-Mg compound fertilizer,boussingaultite,by the reaction of the mineral shoenite from Kunteyi Salt Lake,Qinghai province,and the industrial by-product ammonium sulfate,the solubilities of the quaternary system(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O at 25.0℃in the isothermal evaporation and crystallization process were measured using the isothermal evaporation method,and the corresponding phase diagrams were plotted.According to the diagram,this system contains six saturation points and six solid phase fields of crystallization,which correspond to(K1-m,(NH_(4))m)_(2)SO_(4),(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O,K_(2)SO_(4)·MgSO_(4)·6H_(2)O,MgSO_(4)·6H_(2)O,(K1-n,(NH_(4))n)_(2)SO_(4)·MgSO_(4)·6H_(2)O and MgSO_(4)·7H_(2)O,respectively.By analyzing and calculating the isothermal evaporation and dissolution phase diagram of this quaternary system at 25.0℃,K_(2)SO_(4)and(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O can be separated via K_(2)SO_(4)·MgSO_(4)·6H_(2)O and(NH_(4))_(2)SO_(4)as raw materials.Theoretical calculations about the proposed process were carried out and verified by experiment,which indicated that the yield of potassium sulfate was improved and the magnesium resources were fully utilized.

关 键 词：industrial application N-Mg compound fertilizer shoenite salt lake brine SOLUBILITY phase diagram Qinghai province 

分 类 号：TQ444[化学工程—化学肥料工业]