Study on interparticle interaction for dry HGMS system using pneumatic conveyance

Abstract

The interfusion of ferromagnetic impurities such as metallic wear debris has been one of the problems in the manufacturing process of powder products. To remove such debris, we developed high gradient magnetic separation system (HGMS) under dry process which has many advantages over the conventional HGMS system under wet process. In dry condition, interparticle forces such as van der Waals’ force, the liquid bridge force and the electrostatic force contribute to aggregation of particles. This leads to the blockage of magnetic filter which is the major problem of dry HGMS system. To solve this problem, we developed dry HGMS system using pneumatic conveyance.In order to investigate the mechanism of powder aggregation in dry HGMS, it is necessary to simulate the behavior of particles considering interparticle interaction. Therefore we conducted the numerical analysis of the behavior of particles using discrete element method (DEM). As a result, the calculated values of repose angle showed a good agreement with measured value. On the basis of the results above, we succeeded in expressing the magnetic aggregation behavior which is one of the characteristics of the mixed powder containing ferromagnetic particles.