大柴旦富硼浓缩盐卤中硼酸镁盐稀释结晶动力学（英文）

Crystallization Kinetics of Mg-Borates Precipitating from Diluted Boron-Containing Brine of Da Qaidam Saline Lake

采用动力学法研究了富硼浓缩盐卤稀释过程硼酸镁盐的结晶动力学,重点探讨了温度、稀释比和硼浓度对结晶过程的影响。利用单纯形优化法配合Runge-Kutta微分方程组数值解法对实验数据进行拟合,给出了结晶动力学方程和结晶速率。结果表明,低温、高硼浓度和中间稀释比有利于硼酸镁盐的结晶析出,最优条件下析硼率(以B2O3计)高达88%;结晶速率随硼浓度的增加和温度的降低快速增大;反应级数表明稀释结晶过程硼酸镁盐结晶主要受多核表面反应控制,同时提出了结晶相转化机理。

The crystallization kinetics of Mg-borates from different diluted brines was investigated by dynamical method.With the aid of simple optimum method and Runge-Kutta digital solution of differential equations,the experimental data was fitted by computer and the optimum kinetic equations of Mg-borates were obtained.Factors such as temperature,mass dilution ratios and boron concentrations during crystallization were tested.The crystallization rate was also calculated based on the kinetic equations.The results show that low temperature,high boron concentration and medium dilution ratio favor the Mg-borates crystallization.The boron yield would be more than 88%in B2O3 under the optimized condition.The kinetic parameters indicate that almost all of the crystallization mechanisms of Mg-borates in diluted brine are polynuclear layer controlled growth.Besides,the crystallization reactions in diluted solutions were also proposed.