针对球形氯化钾结晶过程与聚结机理不明的问题,以冷却结晶法通过过程取样制备与表征了两种不同形貌的氯化钾在不同结晶阶段的晶体形貌与粒度分布特征,从而对比分析了球形氯化钾的结晶过程。并从结晶热力学、经典浸润理论和Lifshitz-Van der Waals酸碱理论出发解释了球形氯化钾形成的主要机理是添加剂的添加减小了结晶体系的介稳区宽度及增大了晶体颗粒在结晶溶剂中的粘附自由能,导致结晶体系更容易以聚结的方式实现球形结晶。介稳区宽度减小和晶体颗粒在结晶溶剂中粘附自由能增大的同步调控有助于实现氯化钾的球形结晶。

Aiming at the problems of unknown crystallization process and agglomeration mechanism of spherical KCl,two different morphologies of KCl at different crystallization stages were prepared and the crystal morphology and particle size distribution were characterized by cooling crystallization method through process sampling.Thus,the crystallization process of spherical KCl was comparatively analyzed.Based on the thermodynamics of crystallization,the classical Wetting Theory and the Lifshitz-Van der Waals acid-base approach,it was explained that the main mechanism of the formation of spherical KCl was that the width of crystallization metastable zone had been narrower and the adhesion free energy between crystal particles in the solution had been increased by addition of additives.Therefore,it was easier for the system to achieve spherical crystallization by agglomeration.The simultaneous adjustment of the reduction of the metastable zone and the increase of adhesion free energy between crystal particles in the solution was helpful to realize the spherical crystallization of KCl.