In-situ study on the heterocoagulation between fine coal particles and coarse glass beads by the particle vision and measurement (PVM) techniques

Abstract

Heterocoagulation between mineral particles is an important phenomenon in mineral processing. Although various characterization methods have been available for characterizing heterocoagulation, in-situ characterization techniques are still lacking. In the present work, a novel in-situ particle vision and measurement (PVM) system was developed to investigate heterocoagulation between coarse and fine particles, which is consistent with the common situation of mineral processing. The heterocoagulation between fine coal particles and coarse glass beads was observed at different pH values and stirring speeds. It was found that the heterocoagulation degree decreased with the increase of pH, which is consistent with the DLVO theoretical calculation results. The heterocoagulation degree decreased with the increase of stirring speed. This indicated that heterocoagulation can be inhibited by high intensity conditioning. Moreover, it was observed that the coated coal particles were not randomly distributed on the glass bead surface. Under certain hydrodynamic conditions, the coal particles were even more distributed at the rear of the glass bead. It is concluded that the microhydrodynamics has a significant effect on the collision frequency and heterocoagulation.