Characterization of powder mixers based on mechanical energy using soft dye granules

摘要

In this paper, we have proposed a method to characterize various type of powder mixers based on the mechanical energy applied to the powders during the mixing operation using the soft dye gradules (the agglomerates of fine Fe_2O_3 particles) as a stress-sensing material (SSM). The disintegration process of Fe_2O_3 agglomerates in the bulk CaCO_3 powder was expressed by means of a simplified comminution model and the future of agglomerates was dealt with as well as that of brittle materials. The energy required to disintegrate the Fe_2O_3 agglomerates was estimated in a high-speed agitating-type mixer and related to the mixing time. The disintegration energy in a bead mill agreed with the net applied energy estimated by using spherical copper particles as a SSM. It has been proved that the mechanical energy is quantitatively evaluated in various powder mixers. By using the change in the disintegration energy with the mixing time, i.e. the energy characteristic curve, the powder mixers can be characterized on the uniform scale of mechanical energy regardless of equipment structure and the principal mixing mechanism in each mixer can be clarified.