1 - Particulate crystal characteristics

Abstract

This chapter discusses the characteristics of particulate crystals. The internal crystal structure and external particle characteristics of size and shape are important indicators of product quality as well as can affect downstream processing, such as solid–liquid separation markedly. Larger particles separate out from fluids more quickly than fines and are less prone to dust formation, while smaller particles dissolve more rapidly. The ideal solid crystal comprises a rigid lattice of ions, atoms, or molecules, the location of which is characteristic of the substance. The regularity of the internal structure of this solid body results in the crystal having a characteristic shape; smooth surfaces or faces develop as a crystal grows, and the planes of these faces are parallel to atomic planes in the lattice. A particular feature of crystals is that the angles between two corresponding faces of a given substance are constant, reflecting their internal lattice structure. The relative size of the individual faces can vary, however, changing the overall growth, shape, or habit, but corresponding angles remain constant. Thus, in practice, two crystals rarely look exactly alike because of the different conditions experienced during their growth histories.