Stable (solid+liquid) phase equilibrium for the ternary systems (K2SO4+KH2PO4+H2O), (K2SO4+KCl+H2O) at T=313.15K

The phase equilibria relationship between the quaternary system LiCl−KCl−Li 2 SO 4 −K 2 SO 4 −H 2 O and its subsystems LiCl−KCl−H 2 O and LiCl− Li 2 SO 4 −H 2 O was studied by the isothermal dissolution equilibrium method at 288.15 K, and the corresponding phase diagrams were drawn. At 288.15 K, ternary systems LiCl−KCl−H 2 O and LiCl−Li 2 SO 4 −H 2 O all belong to the simple type. In the phase diagram of the quaternary system LiCl−KCl−Li 2 SO 4 −K 2 SO 4 −H 2 O, there are five equilibrium solid phase crystallization fields: LiCl•2H 2 O, KCl, Li 2 SO 4 •H 2 O, K 2 SO 4 , and Li 2 SO 4 •K 2 SO 4 .Compared with the multitemperature phase diagrams of this system at 288.15−348.15 K, it was found that the basic configuration of the phase diagrams is the same. As the temperature increased, the phase region of double salt Li 2 SO 4 •K 2 SO 4 clearly increased, whereas the phase region of single salt KCl and K 2 SO 4 clearly decreased. On the basis of the experiment, the extended Harvie−Weare model of the Pitzer model was used to predict the solubility data of the quaternary system. The simulated and measured values were basically in good agreement.

Section: Resultssupporting

confidence: 86%

Measurement and Prediction of Solid + Liquid Equilibria in the Quaternary System LiCl–KCl–Li₂SO₄–K₂SO₄–H₂O at 288.15 K

Cui

Dong

2019

“…However, the coexistence of the salts has greatly influenced the application of such resources. , Data of solubility in water–salt systems supply a very important foundation for the separation and purification progress. So the investigation of phase equilibria plays an important role in the process of the rational use of salt resources and industrial applications. − For example, Li + always coexists with Mg 2+ , so the lithium resource separation process is according to the solubility phenomenon. , Similarly, industrial KH 2 PO 4 can be prepared by an ion exchange method, direct chemical conversion method, crystallization method, and solvent extraction method with KCl based on phase equilibria. , However, new compounds and a solid-solution were often formed in the mixed electrolyte systems contain Cs + . For example, Jendoubi et al studied the mixing enthalpies in the solid-solution (Cs 1– x ,Rb x )NO 3 at temperatures from 298.15 to 473.15 K. Yariv et al found that the new salt Cs[Na(H 2 O)] 2 Br 3 and solid-solution Cs 1– x [Na(H 2 O)] x Br ( x ≤ 0.48) were formed in the ternary system (NaBr + CsBr + H 2 O) at 298.15 K. However, when HCl was added as a solvent in the system CsCl + TbCl 3 + HCl (∼7.6 mass %) at 298.2 K, two new compounds Cs 5 TbCl 8 ·6H 2 O and Cs 2 TbCl 5 ·6H 2 O were found in the system.…”

Section: Introductionmentioning

confidence: 99%

Phase Diagrams and Physicochemical Properties for the Ternary System (CsCl + NaCl + H₂O) at T = (298.15, 308.15, and 318.15) K

Gao

Zhai

et al. 2017

Complete phase diagrams and physico-chemical properties for the ternary system (CsCl + NaCl + H 2 O) were determined at T = (298.15, 308.15, and 318.15) K, respectively. The X-ray diffraction method and Schreinemaker's wet residue method were used to verify the solid phase. The phase diagrams show this ternary system is a complex type. Three crystallization regions were found corresponding to the single salt NaCl, a compound CsCl•2NaCl•2H 2 O, and a solid solution series [Cs 1−x (Na•H 2 O) x ]Cl (x in [Cs 1−x (Na•H 2 O) x ]Cl changed from 0 to 0.43 (298.15 K), 0.39 (308.15 K), and 0.36 (318.15 K) at each temperature. With rising temperature, the crystallization area of NaCl increased, but CsCl•2NaCl•2H 2 O and [Cs 1−x (Na•H 2 O) x ]Cl decreased simultaneously. However, density and refractive index increased with increasing CsCl concentration.

“…Cl – and Na + concentration was determined by Volhard method , with uncertainty of 0.005 and ion balance method with uncertainty of 0.005, respectively . Information of the above-mentioned analytical methods are listed in the literature. , …”

Section: Methodsmentioning

confidence: 99%

Solid–Liquid Equilibria for (NaNO₃ + NaCl + H₂O) and (NaNO₃ + Na₂CO₃ + H₂O) Systems at 313.15 K

Ding

Ren

2019

Self Cite

The salt mixture crystallized and buried underground, as hazardous waste, is not only harmful to the environment but also causes low pollution use resources. Thus, to research the gradual separation processes of pure salts crystallized from high salinity brine of MTO in coal-chemical industry is momentous. The thermodynamic equilibrium of Na + //Cl − , SO 4 2− , NO 3 − , CO 3 2− −H 2 O quinary system is essential to realize zero emissions for high salinity wastewater of MTO. Development of coal chemical industry in high salinity wastewater treatment technology includes the production of sodium sulfate, sodium chloride, nitrate sodium, sodium carbonate (refined industrial salt), and water recycling technology. The phase diagram of salt-water system plays a role in predicting and guiding the purification process, especially crystallization process. The phase equilibrium and physicochemical properties of NaNO 3 + NaCl + H 2 O and NaNO 3 + Na 2 CO 3 + H 2 O systems at the temperature of 313.15 K were obtained by the method of isothermal solution saturation. The results showed that one invariant point, two univariant curves, and three crystallization fields are existed in both of systems. Each invariant point in the phase diagrams was analyzed. The physical properties (η, ρ, pH, n D ) of the systems change regularly with composition change of liquid solution. The quaternary phase equilibrium in Na + //C1 − , CO 3 2− , NO 3 − −H 2 O system at 313.15 K was also researched by means of the thorough and intermediate translation techniques together. Thus, the research results, especially the crystalline regions, would be of great value in designing and optimizing the crystallization process of NaCl and other salts in high salinity brine treated of Methanol to Olefins (MTO) technology.