353.15 K下三元体系KCl-KH_(2)PO_(4)-H_(2)O和KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O固液相平衡测定与关联  

Determination and correlation of solid-liquid equilibria for ternary systems KCl-KH_(2)PO_(4)-H_(2)O and KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O at 353.15 K

作　　者：陈艳[1] 李天祥[1] 王肖丽 邓文清 樊小娟 朱静[1] CHEN Yan;LI Tian-xiang;WANG Xiao-li;DENG Wen-qing;FAN Xiao-juan;ZHU Jing(School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,Guizhou Province,China)

机构地区：[1]贵州大学化学与化工学院,贵州贵阳550025

出　　处：《化学工程》2022年第6期43-49,共7页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(21868010);贵州省科技计划项目(黔科合平台人才[2018]5781号)。

摘　　要：采用等温溶解平衡法研究353.15 K下三元体系KCl-KH_(2)PO_(4)-H_(2)O和KH_(2)PO_(4)-CO(NH_(2))2-H_(2)O的固液相平衡关系,平衡固相组成采用湿渣法与X射线衍射法相结合的方法进行鉴定。用实验数据绘制了353.15 K下2个三元体系的平衡相图,结果表明:在353.15 K下三元体系KCl-KH_(2)PO_(4)-H_(2)O和KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O均为简单共饱和型,相图均包含1个共饱和点,2条单变量曲线,3个结晶区。其中,三元体系KCl-KH_(2)PO_(4)-H_(2)O共饱和点的对应的平衡固相为KCl与KH_(2)PO_(4)的混合物,三元体系KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O共饱和点对应的平衡固相为CO(NH_(2))_(2)与KH_(2)PO_(4)的混合物,均未形成固溶体和复盐。运用Pitzer模型和Wilson模型分别对2个体系进行关联计算,结果表明:KCl-KH_(2)PO_(4)-H_(2)O体系的Pitzer模型计算结果与实验结果的平均相对偏差为0.04%;KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O体系的Wilson模型计算结果与实验结果的平均相对偏差为0.95%,溶解度理论计算值与实验值基本一致。The solid-liquid equilibria of ternary systems KCl-KH_(2)PO_(4)-H_(2)O and KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O at 353.15 K were studied by isothermal dissolution equilibrium method,and the composition of equilibrium solid phase was identified by the wet slag method combining with X-ray diffraction method.The equilibrium phase diagrams of the two ternary systems at 353.15 K were drawn with the experimental data.The results show that the ternary systems KCl-KH_(2)PO_(4)-H_(2)O and KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O at 353.15 K are simple co-saturatedsystems,and each of the two phase diagrams contains one co-saturation point,two univariate curves and three crystallization regions.Among them,the equilibrium solid phase corresponding to the co-saturation point of the ternary system KCl-KH_(2)PO_(4)-H_(2)O is a mixture of KCl and KH_(2)PO_(4),and the equilibrium solid phase corresponding to the co-saturation point of the ternary system KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O is CO(NH_(2))_(2) and KH_(2)PO_(4) mixture,neither solid solution nor double salt is formed.The Pitzer model and Wilson model were used to fitting the two systems,respectively.For the ternary system KCl-KH_(2)PO_(4)-H_(2)O,the average relative deviation is 0.04%.For the ternary system KH_(2)PO_(4)-CO(NH_(2))_(2)-H_(2)O,the average relative deviation is 0.95%,The results show that the calculated data and the experimental data are basically consistent.

关 键 词：溶解度 相平衡 水盐体系 PITZER模型 Wilson模型 

分 类 号：TQ44[化学工程—化学肥料工业]