Study of Phase Equilibrium of NaBr + KBr + H2O and NaBr + MgBr2 + H2O at 313.15 K

Qing, Chen; She, Jiping; Xiao, Yang

doi:10.1155/2017/2319635

Cited by 5 publications

(1 citation statement)

References 8 publications

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“…This hypothesis is plausible taking into account the long-debated topic of mixed anhydrous or hydrated mixed Na + K + bromide solid solutions. While NaCl and KCl can give a stable substitutional crystal, NaBr and KBr are much less compatible, and only very recently a mixed metastable 50:50 anhydrous Na 0.5 K 0.5 Br single crystal structure was solved at 328 K. Such crystal evolves to the mixture of pure salt at room temperature and is not stable below 150 K. The same mixture in the presence of water is much more complicated, , but modeling data suggest that some degree of solubility in such complex system is indeed plausible and it is the unique explanation of the absence of KCl of KBr phases in all XRPD data. The impossibility of carrying out a structural refinement with pure NaBr phases could also be due to this vicariance, able to significantly modify the intensity of the observed peaks.…”

Section: Resultsmentioning

confidence: 99%

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

Lopresti

Mangolini

Conterosito

et al. 2023

Crystal Growth & Design

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Eutectic mixtures are usually studied by differential scanning calorimetry (DSC), able to identify the transition temperatures, possible hysteresis, and investigate the energetic features of transformations. However, DSC is not able to give compositional, structural, or morphological information. A new approach is proposed exploiting powder X-ray diffraction (XRPD) and imaging to overcome the issues posed to diffraction by the presence of an amorphous liquid phase. Principal component analysis (PCA) is applied blindly to in situ XRPD data from both solid and liquid phases in an approach called differential scanning diffraction (DSD), with PCA scores being the reaction coordinate of melting or crystallization steps. PCA was used in a similar way to analyze the imaging data in what was named differential scanning imaging (DSI). Exploiting this approach, the structural and morphological changes during phase transitions can be characterized by XRPD and imaging respectively, complementarily to the energetic effects probed by DSC. Melting and crystallization points can be identified together with the hysteresis between downward and upward temperature ramps, by the structural and morphological viewpoints. A three-component mixture (NaBr, KCl, and water), with wide industrial applications, was studied to describe the behavior around the eutectic composition and examine how small mixture changes can affect the transition temperature and the freezing/melting behaviors. The phase composition at the solid state was elucidated and a new phase of NaBr was identified and its lattice parameters were obtained by XRPD. DSD and DSI resulted complementary to traditional DSC data with many potential applications in solid state chemistry and materials science.

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Section: Resultsmentioning

confidence: 99%

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

Lopresti

Mangolini

Conterosito

et al. 2023

Crystal Growth & Design

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Phase Equilibria and Phase Diagrams of Na⁺//F^–, CO₃^2–, PO₄^3–-H₂O Quaternary and Subsystems at 313.15 K

et al. 2021

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Rare-earth ore concentrate is calcined at high temperature by the alkaline method, and the associated elements fluorine and phosphorus are enriched in the form of sodium fluoride and sodium phosphate in water elution. To separate and recover fluorine and phosphorus from the aqueous solution, the solid−liquid equilibrium behaviors of the quaternary systems Na + //F − , CO 3 2− , PO 4 3− -H 2 O and their two sub-ternary systems NaF-Na 3 PO 4 -H 2 O and Na 2 CO 3 -Na 3 PO 4 -H 2 O at 313.15 K were studied via the isothermal solubility phase equilibrium method. Solubility data, liquid density and pH, two complete isothermal phase diagrams of the ternary system, and one complete isothermal phase diagram of the quaternary system were obtained. The results showed that two double salts NaFoccurred in the respective ternary systems. Five solid species of one anhydrous salt of NaF, two hydrous salts of Na 2 CO 3 •H 2 O and Na 3 PO 4 •12H 2 O, and two double salts of Na 3 PO 4 •3Na 2 CO 3 •8H 2 O and NaF•2Na 3 PO 4 • 19H 2 O were found in the quaternary system. The phase diagram of the quaternary system consisted of three invariant points, five crystallization regions, and seven univariate curves. Na 3 PO 4 easily combined with NaF to form double salt NaF•2Na 3 PO 4 •19H 2 O, which occupied a larger phase region in the quaternary phase diagram. The increase in Na 2 CO 3 will lead to the decrease in the solubility of Na 3 PO 4 and NaF in the system.

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Measurements of Solid–Liquid Equilibria in the Quaternary Systems LiBr–NaBr–KBr–H₂O and LiBr–KBr–SrBr₂–H₂O at 308.15 K

Guo

Sang

2022

J. Chem. Eng. Data

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The underground brines in the Sichuan basin of China are rich in many valuable components, such as Li+, K+, Sr2+, Br–, and others. In view of comprehensive utilization of the underground brines, the stable solid–liquid equilibria of the quaternary systems LiBr–NaBr–KBr–H2O and LiBr–KBr–SrBr2–H2O at 308.15 K were measured by the isothermal dissolution equilibrium method. The results show that both phase diagrams of the quaternary systems listed above are hydrate-type. Both equilibrium phase diagrams are composed of two invariant points, five univariant curves and four crystallization fields. The equilibrium solid phases in the first quaternary system are LiBr·2H2O, NaBr·2H2O, NaBr, and KBr, respectively, and those in the second quaternary system are LiBr·2H2O, SrBr2·6H2O, SrBr2·2H2O, and KBr. In both phase diagrams, the crystallization field of KBr is the largest, while that of LiBr·2H2O is the smallest. The results indicate that KBr is the easiest to be separated from the saturated solution in the two quaternary systems. Furthermore, the comparison of phase equilibria of the quaternary systems and its ternary subsystems at different temperatures is presented and discussed in detail.

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Study of Phase Equilibrium of NaBr + KBr + H₂O and NaBr + MgBr₂ + H₂O at 313.15 K

Cited by 5 publications

References 8 publications

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

Phase Equilibria and Phase Diagrams of Na⁺//F^–, CO₃^2–, PO₄^3–-H₂O Quaternary and Subsystems at 313.15 K

Measurements of Solid–Liquid Equilibria in the Quaternary Systems LiBr–NaBr–KBr–H₂O and LiBr–KBr–SrBr₂–H₂O at 308.15 K

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Study of Phase Equilibrium of NaBr + KBr + H2O and NaBr + MgBr2 + H2O at 313.15 K

Cited by 5 publications

References 8 publications

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

PCA Analysis of In Situ X-ray Powder Diffraction and Imaging Data Shedding New Light on Solid-State Transformations: The Crystallization of Low Temperature Eutectic Mixtures

Phase Equilibria and Phase Diagrams of Na+//F–, CO32–, PO43–-H2O Quaternary and Subsystems at 313.15 K

Measurements of Solid–Liquid Equilibria in the Quaternary Systems LiBr–NaBr–KBr–H2O and LiBr–KBr–SrBr2–H2O at 308.15 K

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Study of Phase Equilibrium of NaBr + KBr + H₂O and NaBr + MgBr₂ + H₂O at 313.15 K

Phase Equilibria and Phase Diagrams of Na⁺//F^–, CO₃^2–, PO₄^3–-H₂O Quaternary and Subsystems at 313.15 K

Measurements of Solid–Liquid Equilibria in the Quaternary Systems LiBr–NaBr–KBr–H₂O and LiBr–KBr–SrBr₂–H₂O at 308.15 K