Effect of Tensile Strength on Torque for Wet-Powder Mixing

Abstract

The tensiling process curves for powders with various moisture contents have been experimentally obtained in order to correlate the mixing torque with the tensile strength. From the trend between the breakup displacement and the moisture content, the powders were able to be classified into three states, according to the region of moisture content: the pendular state (region I), the funicular state (region II) and the transition state from the funicular to the capillary state (region III). For the powders in the region I or II, the tensile strength increased with increasing moisture content. In the region III, however, the tensile strength was nearly constant or reached a maximum value and then reduced with increasing the moisture. The mixing torque for moist powders was excellently correlated with the tensile strength obtained by the tensile tests for the powders with the void fraction identical to that for the torque measurement.