Phase Equilibria and Phase Diagrams for the Aqueous Ternary System Containing Sodium, Sulfate, and Metaborate Ions at 288.15 and 308.15 K and 101.325 kPa

Abstract

Solubilities and physicochemical properties (density and refractive index) for the ternary system (Na+//SO4 2–, BO2 –-H2O) at (288.15 and 308.15) K and 101.325 kPa were studied by the isothermal dissolution equilibrium method. Phase diagrams and diagrams of the physicochemical properties (density and refractive index) were plotted against the concentration of sodium sulfate. For both temperatures, the phase diagrams contained one invariant point, two univariant curves, and two crystallization regions corresponding to sodium metaborate tetrahydrate (NaBO2·4H2O, Nb) and mirabilite (Na2SO4·10H2O, Mir) at 288.15 K, and Nb and thenardite (Na2SO4, Th) at 308.15 K, respectively. The area of the crystallization region of sodium metaborate tetrahydrate was enlarged with the increase of temperature, and the solid phase of mirabilite transformed into thenardite when the temperature increased from 288.15 to 308.15 K. The physiochemical properties including density and refractive index of the system at (288.15 and 308.15) K were similarly increased first and decreased later with the increase of sodium sulfate concentration in the equilibrium solution. The experimental data of the density and refractive index were correlated using the empirical equations, and the calculated and experimental values agreed well.

Solubilities, Densities, and Refractive Indices of the Ternary System (NaBO2 + KBO2 + H2O) at T = (298.15 and 323.15) K and P = 0.1 MPa

“…The form of boron species is affected by the pH, temperature, solution concentration, and so forth. The phase equilibrium of systems containing metaborate at multitemperatures has been reported, such as (NaCl + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, , (Na 2 SO 4 + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, , (NaOH + NaBO 2 + H 2 O) and (KOH + KBO 2 + H 2 O) at (283.15, 298.15, and 323.15) K, and (KBO 2 + LiBO 2 + H 2 O) and (NaBO 2 + LiBO 2 + H 2 O) at 298.15 K . The system (NaBO 2 + KBO 2 + H 2 O) is not only one of the most indispensable subsystems of the complex composition in Chaerhan Salt Lake brines, which should be studied primarily, but also is the theoretical guidance for separating boron salts from the brines.…”

“…Because the behavior of boron dissolution is very complex, borate exists in aqueous solution in the form of different species, such as 5 The form of boron species is affected by the pH, temperature, solution concentration, and so forth. The phase equilibrium of systems containing metaborate at multitemperatures has been reported, such as (NaCl + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, 6,7 (Na 2 SO 4 + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, 7,8 (NaOH + NaBO 2 + H 2 O) and (KOH + KBO 2 + H 2 O) at (283.15, 298.15, and 323.15) K, 9 and (KBO 2 + LiBO 2 + H 2 O) and (NaBO 2 + LiBO 2 + H 2 O) at 298.15 K. 5 The system (NaBO 2 + KBO 2 + H 2 O) is not only one of the most indispensable subsystems of the complex composition in Chaerhan Salt Lake brines, which should be studied primarily, but also is the theoretical guidance for separating boron salts from the brines. Aiming to utilize effectively the valuable potassium and boron brine resources, the phase equilibria of the ternary system (NaBO 2 + KBO 2 + H 2 O) at (298.15 and 323.15) K were determined, which can offer essential data for clarifying the formation and evolution law and formulating the process of extracting potassium and boron.…”

Solid–Liquid Phase Equilibria of the Reciprocal Quaternary System (Li + Na + Cl + BO2 + H2O) at 288.15 K and 0.1 MPa

“…There are four boundary ternary subsystems in this quaternary system (Li + Na + Cl + BO 2 + H 2 O), which are (LiCl + LiBO 2 + H 2 O), (NaBO 2 + LiBO 2 + H 2 O), (NaCl + NaBO 2 + H 2 O), and (NaCl + LiCl + H 2 O). ,− The measured solubility data of three ternary systems are shown in Table , and the ternary system (NaBO 2 + LiBO 2 + H 2 O) was determined in this work. The deviation of measured solubility data obtained with previous reports is less than 0.05%, suggesting that our experimental procedure and results are rational and reliable.…”

Measurement of Specific Heat Capacity of NaBO2(aq) Solution and Thermodynamic Modeling of NaBO2 + H2O, NaBO2 + NaCl + H2O, and NaBO2 + Na2SO4 + H2O Systems

“…With respect to the NaBO 2 + Na 2 SO 4 + H 2 O system, only Skvortsov et al and Chen et al , reported the experimental solubility data. At 298.15 K, the solubility isotherm reported by Skvortsov et al is significantly different from the recent data of Chen et al and indicates the formation of a double salt NaBO 2 ·Na 2 SO 4 ·14H 2 O and a solid solution m NaBO 2 · n Na 2 SO 4 · x H 2 O.…”