QUANTITATIVE CHARACTERIZATION OF MIXING OF DRY POWDERS IN V-BLENDERS

Experiments were conducted to determine the effect of rotation rate, f ill level, and total number of revolutions on the mixing performance o f a V-blender. The experiments were performed using 66-mu m red and gr een glass beads. Mixture uniformity was quantified after each experime nt by infiltrating the mixtures with a binder, and using image analysi s to examine slices of the solidified mixture. The mixing rate (as a f unction of total revolutions) was not affected by changing the rotatio n rate between 8 and 24 Ipm. The mixing rare increased significantly a s the fill percentage was decreased from 60% to 40% of the total vesse l volume. In a symmetric blender such as a V-blender, the rate of mixi ng is limited by the rate of mass transfer across the vessel plane of symmetry orthogonal to the mis of rotation. A one-parameter model base d on the amount of material that crossed the plane of symmetry per rev olution displayed good agreement with the experimental data.