Application of gamma emission imaging in mineral processing industry: case study of slurry transport in a wet laboratory ball mill

Abstract

The gamma emission imaging technique has been effectively applied for determination of the slurry radial flow pattern and mixing profile within the ball charge in a wet laboratory ball mill. Aqueous technetium, Tc99m radioisotope that emits 140 keV photons with a short half-life of 6.02 h, was utilized as a flow follower while the glycerol–water mixture was used to mimic the motion of the actual slurry as found in full scale systems. Tests were conducted under two different slurry viscosity conditions for two mill speed levels. Both qualitative and quantitative information of the slurry radial flow and mixing behaviour inside the mill were obtained. The slurry flow and mixing behaviour displayed a marked dependence on the mill speed and slurry viscosity. The slurry mixing time in the ball charge varied directly with the slurry viscosity but inversely with the mill rotational speed.