What is the compressibility and Hausner ratio?

The compressibility and the Hausner ratio can be calculatedusing the bulk density and the tapped density, which are utilized to indicate the flowability of powder material.

The calculation of the compressibility:

The calculation of the Hausner ratio:

where ρT is the tapped density, and ρB is the bulk density.

The flowability of a powder can be characterized based on the compressibility or the Hausner ratio. A lower compressibility or a lower Hausner ratio of a material indicates better flow properties. A compressibility of <10 or a Hausner ratio of <1.11 is considered an “excellent” flow, whereas a compressibility of >38 or a Hausner ratio of >1.60 is considered a “very poor” flow.

The flowability of a powder material can be evaluated by integrating the compressibility, the Hausner ratio, and the angle of repose. It is also possible to predict the flowability of the material through individual parameters.