25℃ K_2SO_4·MgSO_4·6H_2O与KCl转化结晶K_2SO_4动力学与机理研究  

Study on the Kinetics and Mechanism of K_2SO_4 Crystallizing from K_2SO_4·MgSO_4·6H_2O and KCl at 25 ℃

作　　者：胡天琦 张志宏[2] 董欧阳[2] 赵冬梅[2] 马艳芳[2] 付振海[2] 王健康[1,2] 

机构地区：[1]中国科学院青海盐湖研究所,西宁810008 [2]中国科学院大学,北京100049

出　　处：《人工晶体学报》2016年第2期309-315,共7页Journal of Synthetic Crystals

基　　金：青海省科技支撑项目(2013-G-139A;2013-G-115A)

摘　　要：研究了25℃条件下软钾镁矾和氯化钾转化结晶硫酸钾的过程,针对不同时刻液相进行化学分析及固相鉴定;结果表明在该体系下,氯化钾溶解速率大于软钾镁矾的溶解速率;硫酸钾结晶发生迅速。采用非线性拟合计算硫酸钾结晶的量以及软钾镁矾和氯化钾溶解的量与时间的关系。结合动力学模型模拟计算得到溶解和结晶动力学方程,提出了溶解及结晶转化机理,得出在25℃条件下体系结晶和溶解均符合Stumm模型,溶解过程和结晶过程均属于表面反应控制,反应级数分别为n=1.54,n=0.38。此研究结果对工程设计、工艺优化、过程控制提供了一种新的方法和依据。Transformation crystallization process of potassium sulfate used by picromerite and potassium chloride under the condition of 25 ℃ was studied. The liquid and solid phase were characterized by chemical analysis and solid phase identification,respectively. The results show that potassium chloride dissolved quicker than the picromerite in this system,and the production of potassium sulfate was an extremely fast process. The relationship between the amount of potassium sulfate crystallized and the time was calculated by nonlinear fitting,so were the amount of picromerite and potassium chloride dissolved.Dissolution and crystallization kinetics equations were obtained combined with dynamic model simulation.Dissolution and crystallization transformation mechanism were proposed. Crystallization and dissolution conformed to Stumm model under the condition of this experiment systems. It concluded that dissolving process and crystallization process were controlled by the surface reaction,the dissolving reaction series n= 1. 54,crystallization reaction series n = 0. 38. This research results provide a new method and the basis for engineering design,process improvement,process control.

关 键 词：软钾镁矾 硫酸钾 Stumm模型 动力学 

分 类 号：TQ115[化学工程—无机化工]