ABSTRACT
Particle Density, rp This is defined as the particle mass divided by the particle volume, including the inside closed pores. The volume can be obtained by the method mentioned below.
Bulk Density, rB The bulk density is defined for powder or particle beds. It is given as the ratio of the mass of the powder bed in a vessel to the volume of the bed, including the voids among primary particles. If the values of rp and rB are measured, the porosity or void fraction can be determined by
5 21 ρ ρ
(4.1)
The measurement of the particle’s density consists of measuring its mass and volume. The mass can be accurately measured with an electronic balance. However, it is difficult to measure the volume of particles. As described below, the volume of a particle is determined from the liquid volume increase upon adding the particle to a liquid, or in the case of gaseous medium, it is determined from the increased amount of volume or pressure.
