3.2 Bulk density
The courses of the bulk density values as a function
of the particle size correspond to those for the flow
properties. For the smallest fraction 100 < x < 160 µm,
the bulk densities for the samples of both grinding
methods are the same. This in turn is due to the
certainly higher value of adhesive force/mass force.
With further increasing particle size, the rise in bulk
density values for samples ground in a hammer mill is
larger than for samples ground in a roller mill (Figure 4).
This too can be attributed to the rougher particle surface,
expressed by the fractal dimension. The elongation
evidently exerts less influence in this sector.