Skeletal Density 

The particle skeletal density is the density of the material that constitute the particle, without porosity.
The Solid Skeletal density is to be measured by gas pycnometry thanks to a gas pycnometer (liquid pycnometry is not accurate)
Note : the method presented below is simplified, the objective being to present a concept, not to give an accurate method of calculation.
The volume of solids (excluding the pores), can be calculated thanks to
Equation 1 : deduction of volume of solid from pycnometry experiment
Figure 1 : Measuring skeletal density
The skeletal density can be used to calculate the apparent particle density. It is for this purpose necessary to calculate the porosity of the particle ω_{p} in m3/kg from the experience described above.
Do you want to know more ? www.powderprocess.net is covering all aspects of solids and powder processing and handling The pages below will probably interest you ! 
BULK DENSITY and APPARENT PARTICLE DENSITY Want to know more about powder analysis ? Skeletal density is not the only measure for solids density, find here information on bulk densities (loose and tapped) and apparent particle density 
MIXING All on mixers and mixing principles 
POWDER DISCHARGE All on hopper and silos discharge and good design principles 
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