Crystallization involves every aspect of our daily lives, from food and medicine to fuels that drive community operations. Most agrochemicals and pharmaceuticals undergo many crystallization steps during their development and production. Key food materials such as lactose and lysine are produced by crystallization, and the unwanted gas hydrate crystallization in deep-sea pipelines is a major safety consideration in the petrochemical industry.
In the crystallization process, we need to understand the three definitions of crystallization, crystal and precipitation, among which:
Crystallization: The process of forming a solid crystal from another form, usually a liquid solution or melt.
Crystal: Solid particles that align molecules, atoms, or ions in some fixed and robust repeating three-position modes or lattices.
Precipitation: It is more difficult to define the term precipitation. Some people believe that precipitation is only a very fast or uncontrolled crystallization process. Others believe that precipitation is the formation of crystals caused by chemical reactions.
When crystals have many important properties, the crystal size distribution may have the greatest impact on the quality and performance of the final product (and subsequent process flow). The size and shape of the crystal directly affects the critical steps downstream of the crystallization equipment, and its filtration and drying properties are highly susceptible to these important property changes. Similarly, the final crystal size can directly affect the quality of the final product. In pharmaceutical compounds, bioavailability and efficacy are usually related to particle size. Increasing their solubility and dissolution characteristics usually requires smaller particle sizes. The crystal size distribution can be optimized and controlled by carefully selecting the correct crystallization conditions and process parameters. Understanding how process parameters affect critical transitions (such as nucleation, growth, and damage) allows scientists to develop and manufacture crystals with the desired properties and effectively market them.