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

Abstract

Boron and lithium play an important role in many industries, which are widely distributed in brines of the Qaidam basin. In order to effectively separate lithium and boron mixed salts, the experimental solubilities, solution densities, and refractive indices of the quaternary system (Li + Na + Cl + BO 2 + H 2 O) at T = 288.15 K and P = 0.1 MPa were measured. There are six minerals, corresponding to NaCl, LiCl•2H 2 O, NaBO 2 •4H 2 O, LiBO 2 •8H 2 O, LiBO 2 •2H 2 O, and the double salt NaCl•NaBO 2 •2H 2 O, that existed in this system. LiBO 2 •8H 2 O occupies the greatest part of the phase region, while LiCl•2H 2 O covers the smallest. These results show that LiBO 2 •8H 2 O could be easily crystallized and separated from this system. LiBO 2 •8H 2 O will dehydrate and transform into LiBO 2 •2H 2 O in the concentrated LiCl aqueous solution.

Solid-Liquid Phase Equilibria of the Quaternary System (LiCl + LiBO2 + Li2B4O7 + H2O) at 308.15 K: Experimental and Theoretical Prediction

“…After the brine evaporates, a large amount of NaCl and KCl are precipitated [2], and the composition of brine can be regarded as a complex brine system (Li + , Mg 2+ //Cl − , SO 4 2− , Borate-H 2 O) [3]. e exploitation of lithium from brine resources has become a hot research spot [4,5]. Since boron in brine is usually borate, it also changes correspondingly with the di erence in pH value, coexisting ions, and solution concentration [6].…”