3.2. Bulk density
The bulk density is an important parameter to assess pellet
quality [31], and also the Technical Standard [17] regulates its range
of variability to establish the quality class.
It is defined as the mass of particles of the material divided by
the total volume they occupy that includes particle volume, inter-
particle volume, and internal pore volume.
The storage and transport issues are related to pellet bulk
density because of the economic costs rise if the bulk density is too
low; higher this physical parameter allows to enhance the transport
efficiency and facilities and reduce the costs.
The mean bulk density trend of the two types of pellet blends is
shown in Fig. 3. The black line indicates the minimum threshold