The Influences of Operating Parameters on the Recovery of Coated Single-Core Particles by the Spray Drying of Suspensions.

The coating of fine particle was carried out by spray drying with a pneumatic nozzle. The raw powders that served as the core particles used in the experiments were particles with a narrow size distribution for polishing use. The coating material was ethyl cellulose dissolved in an ethanol and water mixture. The operating parameters were the composition of the suspensions, the concentration of ethyl cellulose and the core particle sizes. The recovery of single-core particles produced by spray drying was able to be formulated as a function of the operating parameters. The factor that most significantly influenced the recovery of single-core particles was particle size. The smaller the size, the less the single-core particles obtained. The thickness of the liquid film which adhered to the surface of a particle was estimated to be around 2.4μm.