Effects of Properties of Crystalline Particles on Mother Liquor Holdup in Crystal Cake and Residue Behaviors of Impurities

Abstract

In industrial crystallization, all impurity species need to be removed, regardless of the kind of impurity present in the raw materials. Removing the mother liquor is required because a crystal cake with mother liquor holdup is frequently formed by crystalline particles during solid-liquid separation in suspension-type melt crystallization. This study aims to make clear the relationship between the mother liquor holdup and the characteristics of the crystal cake, and the difference in residue behaviors of impurities based on the new concept for understanding the mother liquor holdup. As a result, the initial mother liquor holdup depended on the specific surface area of the crystal cake. Investigating the residue behavior of each impurity suggests that the impurity-based inclusion factors were different from the solvent-based inclusion factor depending on the kind of impurity. Furthermore, a certain impurity had a specific surface area dependence of the residual amount of impurity.

Keywords

• Melt crystallization
• Solid-liquid separation
• Mother liquor
• Impurity
• Crystal cake