Mg(BO2)2在MgCl2水溶液中的相平衡与化学平衡

Phase Equilibria and Chemical Equilibrium of Mg(BO2)2 in MgCl2 Aqueous Solution

借助拉曼光谱和X射线衍射(XRD)检测手段,对Mg(BO2)2在MgCl2水溶液中水解的固液相平衡与物种化学平衡规律进行了研究。结果表明,MgCl2对Mg(BO2)2的溶解转化、多硼氧配阴离子的物种分布有很大影响:(1)随着MgCl2浓度从0达到饱和,Mg(BO2)2的表观饱和浓度从0.79%增加到1.96%,pH值从9.96降到6.27;(2)Mg(BO2)2在纯水中水解形成固相Mg2B6O11·15H2O和Mg(OH)2,在MgCl2溶液中形成固相Mg2B6O11·15H2O和Mg3Cl2(OH)4·4H2O;(3)Mg(BO2)2在纯水中水解,硼的物种主要为B4O5(OH)42-和B3O3(OH)4-,分别占液相总硼含量的49.81%和19.54%。在MgCl2饱和溶液中,主要为B3O3(OH)4-和B5O6OH)4-,分别占液相总硼含量的44.57%和40.00%。

The solid liquid phase equilibria and species chemical equilibrium of Mg(BO2)2 dissociated in MgCl2 aqueous solution were studied by means of Raman spectroscopy and X ray diffraction(XRD).The results indicate that the MgCl2 concentration has a great influence Mg(BO2)2 dissociation.(1)With the increasing of MgCl2 concentra-tion from 0 to saturated state,the apparent solubility of Mg(BO2)2 increased from 0.79%to 1.96%,and pH value de-creased from 9.96 to 6.27;(2)Solid species are changed gradually from Mg2B6O11·15H2O and Mg(OH)2,to Mg2B6O11·15H2O and Mg3Cl2(OH)4·4H2O;(3)Main species of polylobate anions change from B4O5(OH)42-and B3O3(OH)4-with the accounts of 49.81%and 19.54%,to B3O3(OH)4-and B5O6OH)4-with accounts of 44.57%and 40.00%respectively.