| 盐卤硼酸盐化学 Ⅹ.MgO·2B2O3-MgCL2-H2O浓盐溶液在20℃时硼酸盐的结晶动力学研究 |
| CHEMISTRY OF BORATE IN SALT LAKE——X. STUDY ON KINETICS OF Mg-BORATE CRYSTALLIZED OUT FROM MgO·2B2O3-MgCl2-H2O SOLUTION |
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| 摘要: 配制MgO·2B2O—MgCl2—H2O浓盐溶液在20℃恒温静置过程中,第一阶段析出MgO·3B2O3·7H2O,第二阶段析出2MgO·2B2O3·MgCl2·14H2O。采用一级和二级混合反应速率模型,用计算机对结晶动力学CB—t实验曲线进行拟合,给出结晶动力学速率方程-r=-dC/dt-k(C-C平衡)2+k'(C-C(平衡))。基于高硼浓盐溶液中硼氧配阴离子是以多粒子共存的设想,提出了这两种水合硼酸镁盐结晶反应过程的机制,结晶过程中溶液pH变化的测定结果证实了这一解释。 |
| 关键词: 硼酸盐 结晶动力学 |
| 基金项目: |
| Abstract: The high MgCl2-concentration solution containing 5.67% MgO·2B2O3 is prepared and set at 20℃. The hydrated Mg-borate crystallized out from the solution at the first period is MgO·3B2O3·7H2O and then 2MgO· 2B2O3-MgCl2·14H2O later. The CB-t kinetic curve can clearly be divided into two parts, the first part corresponds to the kinetic curve of MgO·3B2O3·7H2O and the second part is the kinetic curve of 2MgO·2B2O3·MgCl2·14H2O.The kinetic equation of the crystallization reactions of the two hy -drated Mg-borates was derived and its parameters were calculated by fitting the experimental data, and then the apparent rate constant of reactions with different order is given. According to the form of borates existing in high boron solution, there may exist polyborate ions, such as B2O(OH)6-2 B3O3(OH)4-2 and B4O5(OH)4-2 etc., in MgO·2B2O3-MgCl2-H2O solution with high ionic strength. The mechanism of crystallization reactions of the two hydrated Mg-borates have been discussed. It has further been supported by the results of pH value in solution determined during crystallization. |
| Keywords: borate crystallizatioa kinetics |
| 投稿时间：1987-03-01 |
| 摘要点击次数: 1789 |
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| 高世扬,李气新,夏树屏.盐卤硼酸盐化学 Ⅹ.MgO·2B2O3-MgCL2-H2O浓盐溶液在20℃时硼酸盐的结晶动力学研究[J].无机化学学报,1988,4(2):64-73. |
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