Tell me about bulk density, tap density, and the compressibility index.

Question

Accepted Answer

Bulk density is the mass of a unit volume of a material in its natural state, while tap density is the mass of a unit volume of a material after tapping or vibrating. Compressibility index indicates the ability of a powder to decrease in volume under pressure.

Bulk density is measured by dividing the mass of the material by its volume, typically expressed in g/cm^3.
Tap density is determined by measuring the volume occupied by a powder after tapping or vibrating it in a graduated cylinder.
Compressibility index is calculated as (Tapped density - Bulk density) / Tapped density * 100% and indicates the powder's ability to decrease in volume under pressure.
For example, pharmaceutical companies use these parameters to ensure the quality and consistency of their powder formulations.

Accepted Answer

The bulk density often is the bulk density of the powder “as poured” or as passively filled into a measuring vessel. The tapped density is a limiting density attained after “tapping down,” usually in a device that lifts and drops a volumetric measuring cylinder containing the powder a fixed distance.

Asked in Naari Pharma

Tell me about bulk density, tap density, and the compressibility index.

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