In view of the composition characteristics of lithium, calcium and bromine rich in Nanyishan oil and gas field brine of western Qaidam Basin, Qinghai Province, as well as based on the results reported in relevant literature, the phase equilibrium relationship of ternary system LiBr-CaBr2-H2O at 298.15 K was studied by isothermal dissolution equilibrium method. The equilibrium solid phase crystallization regions, as well as the compositions of invariant point, in phase diagram of this ternary system were clarified. On basis of the above ternary system research, the stable phase equilibria of quaternary systems (LiBr-NaBr-CaBr2-H2O, LiBr-KBr-CaBr2-H2O and LiBr-MgBr2-CaBr2-H2O), as well as quinary systems (LiBr-NaBr-KBr-CaBr2-H2O, LiBr-NaBr-MgBr2-CaBr2-H2O and LiBr-KBr-MgBr2-CaBr2-H2O) were further carried out at 298.15 K. According to the above experimental results, the corresponding phase diagrams at 298.15 K were drawn, which revealed the phase relationship of each component in solution and the law of crystallization and dissolution, and meanwhile summarized changing trends. The research results of this paper lay a foundation for further research on the multitemperature phase equilibria and thermodynamic properties of lithium and bromine containing high-component brine system in later stage, and also provide basic thermodynamic data for guiding the comprehensive development and utilization of this oil and gas field brine resource.
According to the composition characteristics of mineral elements in underground brine in the Sichuan basin of China, the complete phase equilibria and phase diagram of the quinary system LiBr−NaBr−KBr− MgBr 2 −H 2 O were studied at 298.15 K. Using the experimentally determined solubilities and equilibrium solids, the spatial stereo phase diagram of the quinary system, the dry base projection phase diagrams of the saturated surfaces of the four salts MgBr 2 •6H 2 O, KBr, LiBr•2H 2 O, and NaBr•2H 2 O, and the corresponding water content diagrams were plotted, respectively. The experimental results show that at 298.15 K, in addition to the four original components, the anhydrous salt NaBr and the double salt KBr•MgBr 2 •6H 2 O are formed. The phase diagram of the quinary system at 298.15 K contains 10 univariate curves, three invariant points, and six equilibrium solid-phase crystallization regions (KBr crystallization region, NaBr crystallization region, NaBr•2H 2 O crystallization region, MgBr 2 •6H 2 O crystallization region, LiBr•2H 2 O crystallization region, KBr•MgBr 2 •6H 2 O crystallization region). When MgBr 2 •6H 2 O or KBr is saturated, LiBr has a strong salting-out effect on KBr, NaBr, or MgBr 2 and NaBr, while when LiBr•2H 2 O is saturated, MgBr 2 has a salting-out effect on KBr and NaBr. All four saturated projection surfaces have MgBr 2 •6H 2 O, and NaBr is generated. These phase equilibrium data can provide a theoretical basis to guide underground brine mining and extract useful components.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.