Measurements of the Solid–Liquid Phase Equilibria in Quinary System NaBr–KBr–MgBr₂–SrBr₂–H₂O at 323 K

Abstract

In view of the characteristic of the deep underground brine that is rich in sodium, potassium, magnesium, calcium, strontium, chlorine, and bromide in the Sichuan basin, solid–liquid equilibria in quinary system NaBr–KBr–MgBr2–SrBr2–H2O were accurately determined at 323 K by the method of isothermal dissolution equilibrium. According to the experimental data, the three-dimensional equilibrium phase diagram was obtained. It consists of ten univariant curves, three invariant points, and six crystallization regions. The solids in crystallization regions correspond to NaBr·2H2O, NaBr, SrBr2·6H2O, MgBr2·6H2O, KBr, and KBr·MgBr2·6H2O, of which MgBr2·6H2O has the minimum crystallization region and KBr has the largest crystallization region, which is bigger than half of the phase diagram. In addition, two-dimensional projections of the saturation surfaces of KBr, SrBr2·6H2O, and MgBr2·6H2O were also analyzed.

Measurements and Predictions of Phase Equilibria in Quinary System NaBr–KBr–MgBr2–SrBr2–H2O at 273.15 K

“…Li et al 15 In the actual production process, different processes such as low-temperature freezing and high-temperature evaporation are generally used to separate different types of pure salts from brine because temperature has the greatest impact on the evaporation concentration of brine and the salt precipitation law. At present, our research group has studied on the three-dimensional space phase diagram of quinary system NaBr−KBr−MgBr 2 −SrBr 2 − H 2 O at 323 K, 18 which is conducting phase equilibrium research on high-temperature parts. However, the phase equilibria of NaBr−KBr−MgBr 2 −SrBr 2 −H 2 O at 273.15 K have not yet been reported for the low-temperature condition.…”

Studies on Phase Equilibria of the Quaternary System LiBr–KBr–SrBr2–H2O and Ternary System LiBr–NaBr–H2O at 323 K

“…Meng et al studied the stable phase equilibria of NaBr–SrBr 2 –H 2 O, NaBr–CaBr 2 –H 2 O and KBr–SrBr 2 –H 2 O at 288.15 K , on the basis of Pitzer and Harvie–Weare (HW) model, and the binary and mixing Pitzer parameters and solubility equilibrium constants of equilibrium solid salts for the two ternary systems at 288.15 K were acquired. For the underground brines rich in strontium, potassium, and bromine in the western Sichuan Basin, our research group carried out the phase equilibrium study of the bromine-containing water–salt system, and the isothermal phase equilibrium studies of KBr–LiBr–H 2 O, NaBr–KBr–SrBr 2 –H 2 O, NaBr–MgBr 2 –SrBr 2 –H 2 O, and KBr–MgBr 2 –SrBr 2 –H 2 O at different temperatures are reported. − …”

Solid–Liquid Phase Equilibria in the Quinary System NaCl-KCl-MgCl2-SrCl2-H2O at 273 K

“…Until now, studies of phase equilibria of salt−water systems have mainly focused on ternary systems and quaternary systems; however, there is not enough literature on quinary systems, especially the salt−water systems containing potassium, sodium, magnesium, and strontium coexisting simultaneously. So far, our group carried on the studies of phase equilibria in NaCl-KCl-MgCl 2 -SrCl 2 -H 2 O (saturated with NaCl) at 373 K 23 and NaBr-KBr-MgBr 2 -SrBr 2 -H 2 O at 323 K. 24 But there are no reports about the three-dimensional equilibrium phase diagrams or dry-salt phase diagrams of the quinary system NaCl-KCl-MgCl 2 -SrCl 2 -H 2 O at low temperatures. In this paper, the solid−liquid phase equilibria in the quinary system NaCl-KCl-MgCl 2 -SrCl 2 -H 2 O at 273 K were studied.…”