3. Agglomeration phenomenon and Group C subclasses

According to Geldart's classification, group C powders are not fluidizable due to their very high interparticle forces. However, analysis of the literature shows that fluidization of fine powders in the form of agglomerates (clusters) is sometimes possible. The agglomeration of primary particles into larger structures enables a favorable shift in the ratio between interparticle and hydrodynamic forces. The agglomerates can then reach a size of several tens or even hundreds of micrometers, and behave like group A or B particles. As a result, the aeration rate required to form and fluidize these agglomerates is much higher than the minimum fluidization rate of individual particles obtained by conventional correlations