盐卤硼酸盐化学ⅩⅤⅢ·MgO·3B_2O_3-MgCl_2-H_2O浓溶液中六硼酸镁盐结晶动力学

Chemistry of Borate in Salt Lake Brine ⅩⅧ. Study On Crystallization Kinetics of Mg—hexaborates from MgO·3B_2O_3—MgCl_2—H_2O Concentrated Solutions

人工模拟合成B_2O_3/MgO=3的过饱和氯化镁溶液,分别在20～60℃恒温条件下,在密封、无外界扰动条件下进行水合六硼酸镁盐结晶动力学实验测定。最后分离固相,经处理后,用化学分析和物理分析法进行物相鉴定。采用计算机对实验数据进行处理,给出相应的结晶动力学方程。根据硼在水盐溶液中是以多粒子形式共存这一结论,提出不同水合六硼酸镁盐的结晶反应机制。

Supersaturated MgO·3B_2O_3 solution with high concerttration of magnesium chloride in which the concentration of Mg—borate may be as several times high as its equilibrium solubility has been imitatively synthesiZed. The crystallization kinetic experimemts of different hydrated Mg-hexaborates have been carried out without stirring at gjven temperature. The Solid phase was separated and identified by chemical analysis, IR-spectra, X-ray powder diffraction and thermol Analysis. The experimental results show that there appear two hydrated Mg—borates, MgO·3B_2O_3·7H_2O and MgO·3B_2O_3·7(1/2)H_2O, in all the crystalligation process and the crystalligation kinetic curves of the different hydrated Mg—hexaborates at diffetent given temperatures. At last, the crystallization kinetic equations have been giveil and the crystalligation Reaction mechanisms have beensuggested.