Skeletal Density 

The skeletal density is the density of the material that constitute the particle, without porosity
Skeletal density is to be measured by gas pycnometry (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.
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