Abstract
The compacting phenomenon, which was previously observed in the course of mixing and lubrication of a powder, such as microcrystalline cellulose, corn starch, or calcium phosphate, dibasic with 1% of calcium stearate, was examined. The experimental equation on the relationship between changing rate of apparent density of the powder and the cumulative revolution number of the V-type mixer was discussed.[numerical formula] where ρmin is the minimum apparent density duriug lubrication of a powder with 1% of calcium stearate, ρmax is the maximum apparent density of the powder, N is the cummulative revolution number of the mixer from the point of minimum apparent density of the powder, ρN is the apparent density of the powder when cumulative revolution number is N, and a, b, c, and d are constants. The experimental equation was found to fit the phenomenon, even if the filling ratio of the powder to the V-type mixer and the revolution speed of the mixer were varied. The values of constants, a and c, of the experimental equation differed according to the kind of powders, but they were constant, not influenced by the operating conditions. By determining these values, changing rate of apparent density of the powders can be divided into two effects, that of diffusion-adhesion phenomenon and that of transformation-coating phenomenon. Other constants, b and d, of the experimental equation were considered to be related to the speed of each of the above phenomena.
