Coating of Seed Particles in Tumbling Fluidized Bed by Atomizing the Suspensions of Clayey Particles [Translated]

Coating seed particles of 53 to 210 µm with clayey particles was carried out by means of a tumbling fluidized bed in order to enlarge and reuse the clayey particles wasted in producing a carrier for driftless dust formulation. The influence of operating factors on the coating efficiency η and on the growth rate of seed particles was investigated. η varied depending upon thermal operating factors but was not influenced much by mechanical ones. It was found that η was related roughly to RW defined as the ratio of the feed rate of water fed as slurry droplets to the maximum theoretical evaporation rate of water in a coating chamber. η increased with RW. The relationship between η and RW varied with the additive ratio of binder PVA to clayey particles, Cb, and η became high with increasing Cb. The growth rate of seed particles was explained well by an equation derived on the basis of the mass balance of clayey particles in a coating chamber. † This report was originally printed in J. Soc. Powder Technology, Japan, 22(5), 278-287 (1985) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.