35℃时Na2SO4-Mg SO4-(NH4)2SO4-H2O体系相图及其应用  

Phase Diagram of a Na_2SO_4-MgSO_4-(NH_4)_2SO_4-H_2O System at 35℃ and its Application

作　　者：郭宏飞[1] 郭宝曼 张菁[1] 豆帅勇 曹吉林[1] 

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,天津300130

出　　处：《高校化学工程学报》2015年第2期264-269,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21076057)

摘　　要：针对白钠镁矾矿产资源的加工开发,提出以硫酸铵做盐析剂分离白钠镁矾制备镁氮复肥和硫酸钠的设想,采用等温法测定了35℃时Na2SO4-Mg SO4-(NH4)2SO4-H2O四元体系的溶解度,并依据相平衡数据绘制了相图。该相图存在4个共饱点和6个结晶区,6个结晶区分别是Mg SO4·7H2O结晶区,Mg SO4·Na2SO4·4H2O复盐结晶区,Na2SO4结晶区,Na2SO4·(NH4)2SO4·4H2O复盐结晶区,(NH4)2SO4结晶区,以及Mg SO4·(NH4)2SO4·6H2O复盐结晶区,其中Mg SO4·(NH4)2SO4·6H2O的结晶区最大,表明该复盐Mg SO4·(NH4)2SO4·6H2O易于结晶析出。依据相图分析和计算,设计了白钠镁矾矿和(NH4)2SO4为原料制备氮镁复肥和十水硫酸钠的新工艺,新工艺具有生产母液不需蒸发水分,显著节能的优点。A new（NH4）2SO4 salting-out method for producing Na2SO4 and Mg-N compound fertilizers by separating bloedite was proposed, and phase equilibrium of a Na2SO4-Mg SO4-（NH4）2SO4-H2 O quaternary system at 35℃ was studied. The solubility of the Na2SO4-Mg SO4-（NH4）2SO4-H2 O quaternary system was measured using an isothermal method and the phase diagram of this system was investigated. The phase diagram shows that there are six solid phase crystalline zones, which correspond to Mg SO4·7H2O, Mg SO4·Na2SO4·4H2O, Na2SO4, Na2SO4·（NH4）2SO4·4H2O,（NH4）2SO4 and Mg SO4·（NH4）2SO4·6H2O, respectively. Mg SO4·（NH4）2SO4·6H2O has the largest crystalline zone, which indicates that the double salt Mg SO4·（NH4）2SO4·6H2O can be easily crystallized. This study shows that the method to produce Mg-N compound fertilizers and Na2SO4·10H2O using bloedite and（NH4）2SO4 as raw materials has advantages of no water evaporation process and low energy consumption.

关 键 词：白钠镁矾 相平衡 硫酸镁 硫酸铵 氮镁复肥 

分 类 号：O642.42[理学—物理化学] TQ110.2[理学—化学]