Geldart powder categories

Tannous K, Hemati M, Laguerie C. Characteristiques au minimum de fluidisation et expansion des couches fluidi-sees de particules de la categorie D de Geldart. Powder Technology 80 55-72, 1994. 

Geldart (1972, 1973) classified powders into four categories ... 

The properties of concern in this section are to do with behaviour of powders in an aerated state this is relevant in gas fluidization, powder transport and handling. Probably the most important tests in this category are those derived from fluidization and the results of such tests are not necessarily restricted to the area of gas fluidization. It should be emphasized that the following notes apply largely to fine powders (i.e. groups A and AC in Geldart s classification). 

The fluidization characteristics of powders are largely determined by the density and mean size of the particles. Three broad categories of particles can be identified, as shown in Figure 12.8 (Geldart, 1973). These are clearly marked on the figure. 

Geldart (1973) studied the fluidization characteristics of many sorts of powders and then classified their behavior into four categories, as shown in Figure 9.8 ... 

---