Abstract:

Nucleation, as the first step in solution crystallization, is a key factor in determining the quality of crystalline products. Nucleation theory mainly includes classical nucleation theory and non-classical nucleation theory. Compared with the classical nucleation theory with uniform and stable structures such as atoms, ions, or molecules as units, non-classical nucleation theories often consider nanoscale precursors as units, such as ion-associated aggregates, nanoparticles and other non-uniform dynamic structures. As a result, the formation of non-classical nucleation processes is more complex. On the basis of traditional research methods of chemistry, chemical engineering and process systems engineering, it is necessary to make full use of mesoscale scientific research methods to complete the exploration of its core laws. This review summarizes the non-classical nucleation theories such as two-step nucleation theory, pre-nucleation cluster theory, and particle attachment crystallization theory, as well as other new theories proposed in recent years, and analyzes the mesoscale structure and its spatiotemporal dynamic behavior, the idea of revising and optimizing the existing nucleation mathematical model with mesoscale mathematical model is discussed, and the mesoscale research paradigm and theoretical development of crystal nucleation in solution crystallization are prospected.

Key words: nucleation, mesoscale, precursor, EMMS model, two-phase flow, virtual process engineering

摘要：

成核作为溶液结晶的第一步，是决定晶体产品质量的关键因素。目前，成核理论主要包括经典成核理论和非经典成核理论。相比于仅以原子、离子或分子等均匀稳定结构为单元的经典成核理论，非经典成核理论以纳米级前聚体为单元，这类单元涵盖了聚集体、纳米粒子等介尺度非均匀动态结构，导致形成的非经典成核过程更为复杂，需在传统的化学、化学工程和过程系统工程研究方法的基础上，充分利用介尺度科学研究方法完成其核心规律的探究。为此，总结了二步成核理论、预成核团簇理论、粒子附着晶化理论以及其他新提出的非经典成核理论，分析了其中的介尺度结构及其时空动态行为，并探讨了利用介尺度数学模型对现有成核数学模型的修正和优化的思路，最后对溶液结晶中晶体成核的介尺度研究范式及理论发展进行了展望。

关键词: 成核, 介尺度, 前聚体, EMMS模型, 两相流, 虚拟过程工程