Solid–Liquid Equilibrium on the Reciprocal Aqueous Quaternary System Li⁺, Mg²⁺//Cl^–, and Borate–H₂O at 323 K

Abstract

The solid–liquid phase equilibrium in the reciprocal aqueous quaternary system Li+, Mg2+//Cl–, and borate–H2O at 323 K was completed with the isothermal dissolution method. The corresponding physiochemical properties (ρ, ηD) of solutions at equilibrium in the Li+, Mg2+//Cl–, and borate–H2O electrolyte mixtures were determined. The isothermal dissolution phase diagram, the water figure, and the figures for the physicochemical properties (ρ, ηD) depending on the composition were obtained according to values of the Jänecke index. The stable phase diagram contains three invariant points, seven univariant curves, and five crystallization zones. The crystallographic forms of magnesium borate and lithium borate are tetraborate MgB4O5(OH)4·7H2O and Li2B4O7·3H2O, respectively. The size of MgB4O5(OH)4·7H2O crystallization field is the largest among the coexisting salts.

Solid–Liquid Equilibrium of the Quaternary System Lithium, Potassium, Rubidium, and Borate at T = 323 K

“…Accordingly, the study of the solid–liquid equilibrium of the borate-containing system is beneficial to the construction of the phase diagrams of the seven-component complex system. For the borate-containing system, some phase equilibrium research has been done, for example, systems Na + //BO 2 – , OH – –H 2 O at (263, 283, 298, 323) K; , Na + //Br – , SO 4 2– , B 4 O 7 2– –H 2 O and Na + //Br – , B 4 O 7 2– –H 2 O at 323 K; Li + //Cl – (SO 4 2– ), BO 2 – –H 2 O at 323 K; Li + , Na + , K + //CO 3 2– , B 4 O 7 2– –H 2 O at (288 and 298) K; Mg 2+ //Cl – (SO 4 2– ), B 6 O 10 2– –H 2 O at 308 K; Li + (Na + ), Mg 2+ //B 4 O 7 2– –H 2 O at 298 K; Li + , Na + , Mg 2+ //B 4 O 7 2– –H 2 O at 273 K and some phase equilibria on the subsystems of Li + , K + , Rb + , Mg 2+ //Cl – , B 4 O 7 2– –H 2 O studied by our research group. − …”

Solid–Liquid Equilibria of the Quinary System Li+, K+, Mg2+//Cl–, B4O72––H2O at 323.2 K

“…−H 2 O, 10 Li + , Mg 2+ //Cl − − H 2 O, 11,12 Li + , K + //Cl − −H 2 O, 12 K + , Rb + //Cl − −H 2 O, 13 and K + , Mg 2+ //Cl − −H 2 O; 13 quaternary systems Li + , K + , Rb + // borate−H 2 O, 14 K + , Rb + //Cl − , borate−H 2 O, 15 Li + , Rb + //Cl − , borate−H 2 O, 16 and Li + , Mg 2+ //Cl − , borate−H 2 O; 17 quinary systems Li + , K + , Rb + , Mg 2+ //borate−H 2 O, 18, 19 Li + , K + , Rb + , Mg 2+ //Cl − −H 2 O, 20 Li + , K + , Rb + //Cl − , borate−H 2 O, 21 and Li + , Na + , Mg 2+ //Cl − , B 4 O 7 2− −H 2 O. 22 The results of studies show that lithium carnallite LiCl•MgCl 2 •7H 2 O is easily produced in the chloride coexistence system of lithium and magnesium, carnallite KCl•MgCl 2 •6H 2 O is formed in the coexistence system of potassium and magnesium, rubidium carnallite RbCl•MgCl 2 •6H 2 O is found in the chloride type system containing magnesium and rubidium, and solid solution [(K, Rb)Cl] is formed in the coexistence system of potassium and rubidium.…”

Solid–Liquid Equilibrium of Quinary Aqueous Solution Composed of Lithium, Potassium, Rubidium, Magnesium, and Borate at 323.15 K

“…Commonly, the dissolution and crystallization behavior of salts in solution can be obtained through the phase equilibria study of the complex salt–water system at multiple temperatures. Therefore, to understand the thermodynamic behaviors of the borates in aqueous solution, several phase diagrams of the system containing borates have been reported, for example, Na + //BO 2 – , OH – –H 2 O at (263.15–323.15) K; − Li + //Cl – (SO 4 2– ), BO 2 – –H 2 O at 288.15 and 298.15 K; , Na + , Ca 2+ //Cl – , borate–H 2 O and Li + , Na + , Ca 2+ //Cl – , borate–H 2 O at 288.15 K; , Li + , K + //SO 4 2– , B 4 O 7 2– –H 2 O at 288.15 K; Li + , Na + , Mg 2+ //B 4 O 7 2– –H 2 O at 273.15 K; Li + , Na + , K + //CO 3 2– , B 4 O 7 2– –H 2 O and Na + , K + //Cl – , SO 4 2– , B 4 O 7 2– –H 2 O at 298.15 K; , and the phase equilibria of quinary, quaternary, and ternary subsystems of system Li + , K + , Rb + , Mg 2+ //Cl – , borate–H 2 O. − After comprehension of the above research, three forms of boron ions such as BO 2 – , B 4 O 7 2– , and B 5 O 8 – appeared in the solution, and the coexisting ions in the solution and temperature have a direct effect on the structure of boron ion.…”