Uniaxial compaction behaviour and elasticity of cohesive powders

The compression and compaction behaviour of bentonite, limestone and microcrystalline cellulose (MCC) — three cohesive powders widely used in industry were studied. Uniaxial compression was performed in a cylindrical die, 40 mm in diameter and 70 mm high, for three selected cohesive powder samples. The initial density, instantaneous density and tablet density were determined. The influence of maximum pressure and deformation rate was examined. The secant modulus of elasticity Esec was calculated as a function of deformation rate v, maximum pressure p and powder sample. After compaction experiments in hydraulic press at three pressures – p = 30, 45 and 60 MPa – and two different deformation rates, the strength of the produced tablets was examined in a material strength testing machine.From uniaxial compression tests performed on the universal testing machine for loading and unloading, the modulus of elasticity E was calculated on the basis of the first linear phase of unloading. The total elastic recovery of tablets was also obtained.

The compression and compaction behaviour of cohesive powders widely used in industry were studied. Uniaxial compression was performed for three selected cohesive powder samples: microcrystalline cellulose (MCC), bentonite and limestone. The initial density, instantaneous density, tablet density, the secant modulus of elasticity, the strength of tablets and the modulus of elasticity E as well as the elastic recovery of tablets were calculated.Figure optionsDownload as PowerPoint slide