Bulk Density - Definitions
Bulk density includes not only particle mass but also the air entrained in the void spaces between the particles. There are three types of bulk density – loose bulk density, packed bulk density, fluidized bulk density. CEMA defines the bulk density as follows :
Loose Bulk Density - (sometimes called the poured bulk density) of a bulk material is the weight per unit of volume that has been measured when the sample is in a loose, non-compacted or poured condition.
Packed Bulk Density - of a bulk material is the weight per unit volume that has been measured when the sample has been packed or compacted in, for instance, a silo or bin or after containerized transportation.
Since the material is compacted the entrained air is displaced and the void space is reduced. As a result, the value of packed bulk density is higher than that of loose bulk density.
Fluidized Bulk Density - is the apparent bulk density of a material in its fluidized state. It is generally lower than either the packed or loose bulk density due to the air absorbed into the voids.
Bulk density is a property that defines the bulk material as a whole. The density of the individual particle is referred to as the particle density.
Particle Density - is the mass of a particle divided by its volume. For a bulk material, average particle density is used, found by dividing the mass of the material by its volume, excluding the voids.
The unit of bulk density and particle density is kg/m3 or lb/ft3.