一水硫酸锰在H_(2)SO_(4)-H_(2)O二元体系中的结晶动力学研究

Study on crystallization kinetics of manganese sulfate monohydrate in H_(2)SO_(4)-H_(2)O binary system

为提高一水硫酸锰晶体产品质量,指导一水硫酸锰结晶过程设计,使用动态法测定了一水硫酸锰在H_(2)SO_(4)-H_(2)O二元体系中的溶解度,利用Apelblat方程对溶解度进行了拟合,得到了Apelblat方程各参数与p H的关系,结果表明在H_(2)SO_(4)-H_(2)O二元体系中一水硫酸锰饱和溶解度随体系p H的降低迅速下降。在MSMPR结晶系统中测定了不同p H下一水硫酸锰晶体成核与生长速率,结果表明,p H的降低对一水硫酸锰晶体生长有显著促进作用,对晶体成核有抑制作用。以粒数衡算方程为基础对一水硫酸锰晶体的成核与生长速率进行计算,获得了不同p H条件下的成核与生长速率方程,并利用POLY2D方程对一水硫酸锰晶体成核与生长速率进行了拟合。该研究成果可为一水硫酸锰工业结晶过程设计提供参考。

In order to improve the quality of monohydrate manganese sulfate crystal products and guide the design of mono‐hydrate manganese sulfate crystallization process,the solubility data of monohydrate manganese sulfate in the H_(2)SO_(4)-H_(2)O binary system was measured by dynamic method.The solubility data was fitted using the Apelblat equation,and the relation‐ship between the parameters of the Apelblat equation and pH value was obtained.The solubility data showed that in the H_(2)SO_(4)-H_(2)O binary system,the saturation solubility of manganese sulfate monohydrate was rapidly decreased with the de‐crease of system pH.The nucleation and growth rates of monohydrate manganese sulfate crystals were measured at different pH values in the MSMPR crystallization system.The results showed that a decrease in pH had a significant promoting effect on the growth of monohydrate manganese sulfate crystals and an inhibitory effect on crystal nucleation.Based on the particle balance equation,the nucleation and growth rates of monohydrate manganese sulfate crystals were calculated,and the nucle‐ation and growth rate equations under different pH conditions were obtained.Finally,the POLY2D equation was used to fit the nucleation and growth rates of manganese sulfate monohydrate crystals.The relevant research results could provide refer‐ence for the design of industrial crystallization process of manganese sulfate monohydrate.