{"title":"Determination and Correlation of Phase Equilibria of Quaternary System KCl–KH2PO4–CO(NH2)2–H2O and Its Ternary Subsystems at 323.15 and 333.15 K","authors":"Lin-Rui Zhong, Tian-Xiang Li, Lian-Jun Shi, Yan-Feng Sui, Shi-Han Wang, Ze-Yu Meng, Feng Yi, Song-Lin Liu, Jing Zhu","doi":"10.1134/s0036023624600230","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Solid-liquid phase equilibrium of the quaternary system KCl–KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O and its subsystems KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O and KCl–KH<sub>2</sub>PO<sub>4</sub>–H<sub>2</sub>O at 323.15 and 333.15 K were investigated through the isothermal solution equilibrium method in this study. The equilibrium solid phases were determined by Schreinemaker’s wet residue method and X-ray powder diffraction method. The isothermal dissolution phase diagrams of the ternary systems and isothermal dry salt phase diagrams and water diagrams of the quaternary system were plotted based on the measured solubility data. The results indicates that there is one invariant point, two univariant curves, three crystallization regions and one undersaturated solution region in the isothermal dissolution phase diagrams of ternary subsystems KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O and KCl–KH<sub>2</sub>PO<sub>4</sub>–H<sub>2</sub>O. The isothermal dry salt phase diagrams of quaternary system KCl–KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O contain an invariant point, three univariant curves, three crystallization regions. The solubilities of the three systems were correlated and calculated by the extended Pitzer model based on the electrolyte solution theory. The maximum values of relative average deviation (RAD) and root mean square deviation (RMSD) of calculated values and experimental values of the ternary system KCl–KH<sub>2</sub>PO<sub>4</sub>–H<sub>2</sub>O at two temperatures are 1.75%, 0.34, respectively; that of the ternary system KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O are 0.71%, 0.19, respectively; that of the quaternary system KCl–KH<sub>2</sub>PO<sub>4</sub>–CO(NH<sub>2</sub>)<sub>2</sub>–H<sub>2</sub>O are 2.06%, 0.52, respectively; which indicates the model can be used for the correlation calculation of these systems due to good consistency in this study.</p>","PeriodicalId":762,"journal":{"name":"Russian Journal of Inorganic Chemistry","volume":"101 1","pages":""},"PeriodicalIF":1.8000,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Russian Journal of Inorganic Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1134/s0036023624600230","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
Solid-liquid phase equilibrium of the quaternary system KCl–KH2PO4–CO(NH2)2–H2O and its subsystems KH2PO4–CO(NH2)2–H2O and KCl–KH2PO4–H2O at 323.15 and 333.15 K were investigated through the isothermal solution equilibrium method in this study. The equilibrium solid phases were determined by Schreinemaker’s wet residue method and X-ray powder diffraction method. The isothermal dissolution phase diagrams of the ternary systems and isothermal dry salt phase diagrams and water diagrams of the quaternary system were plotted based on the measured solubility data. The results indicates that there is one invariant point, two univariant curves, three crystallization regions and one undersaturated solution region in the isothermal dissolution phase diagrams of ternary subsystems KH2PO4–CO(NH2)2–H2O and KCl–KH2PO4–H2O. The isothermal dry salt phase diagrams of quaternary system KCl–KH2PO4–CO(NH2)2–H2O contain an invariant point, three univariant curves, three crystallization regions. The solubilities of the three systems were correlated and calculated by the extended Pitzer model based on the electrolyte solution theory. The maximum values of relative average deviation (RAD) and root mean square deviation (RMSD) of calculated values and experimental values of the ternary system KCl–KH2PO4–H2O at two temperatures are 1.75%, 0.34, respectively; that of the ternary system KH2PO4–CO(NH2)2–H2O are 0.71%, 0.19, respectively; that of the quaternary system KCl–KH2PO4–CO(NH2)2–H2O are 2.06%, 0.52, respectively; which indicates the model can be used for the correlation calculation of these systems due to good consistency in this study.
期刊介绍：
Russian Journal of Inorganic Chemistry is a monthly periodical that covers the following topics of research: the synthesis and properties of inorganic compounds, coordination compounds, physicochemical analysis of inorganic systems, theoretical inorganic chemistry, physical methods of investigation, chemistry of solutions, inorganic materials, and nanomaterials.
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