True density

Indices are dimensionless parameters derived from various mechanical and physical properties of the tablet blend and resulting compacts. Mechanical properties typically measured include indentation hardness (kinetic and static), elastic modulus, and tensile strength (10,11). Physical properties include particle size, shape, and size distribution, density (true, bulk, and tapped), flow properties and cohesive properties. 

There arc several conventional tests required hy consumers of ground mica. They include screening and Ihe determination of bulk density, true specific gravity, chemical analysis, moisture, free silica, refraction index, oil absorption, brightness, grit content, and aspect ratio. 

When a ceramic material (green or baked) is porous, we speak of true density and apparent density. True density is the density of a ceramic material without pores. In order to determine this, the mass of the object must be known as well as the volume less the pore volume. In figure 9.27 all of this is drawn and some calculations are given. 

Because particles may be hard and smooth in one case and rough and spongy in another, one must express densities with great care. Density is universally defined as weight per unit volume. Three types of densities—true density, particle density, and bulk density—can be defined, depending on the volume of particles containing microscopic cracks, internal pores, and capillary spaces. 

Density (tapped) 0.29 g/cm (Spectrum Quality Products) Density (true) 1.347 g/cm ... 

Bonding index 0.0049 (at compression pressure 177.8 MPa) Density (true) 1.589 g/cm for anhydrous pdactose ... 

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