THE STATISTICS OF THE POWDER COATING PROCESS

General expressions are developed for the limiting variance values of complete segregation and random distribution for agglomerated powder mixtures. In the limits of non-agglomeration these expressions reduce to the established values for free flowing powder mixtures.

The general expressions for agglomerating powders are of little value unless the composition distribution of the agglomerates can be predicted. This has been done for the special case of mixing by the 'coating' process in which fine particles coat the surface of larger carrier particles. The model used assumed that the particles are spherical, that only single coarse particles exist within an agglomerate, that the fine particles will either form a single layer on the coarse carrier or will agglomerate on a nucleus of a single fine particle.