Evaluation of gravitational consolidation of binary powder mixtures by modified Heckel equation

Abstract

Consolidation of powders by tapping is an important quality test but it is time and material consuming, which encourages the use of mathematical modelling. This article aims to study this gravitational consolidation dynamics by using nine binary mixtures consisting of cellets and powdered microcrystalline cellulose (MCC102), differing in size, shape, and consolidation properties. To describe the correlation between number of taps and powder bed density/ porosity, the modified Heckel equation. (MH) was newly introduced and compared to the models by Kawakita (KW) and Varthalis & Pilpel (VP). High coefficients of determination were observed by applying the traditional KW model up to 80% of cellets, while a comparable fitting adequacy was obtained with the MH equation up to 50% of cellets in the mixtures. An increased content of MCC102 increased fitting adequacy in the MH and KW model, whereas a nearly opposite mixture trend was observed for the VP model.