Slurry rheology in mineral processing unit operations: A critical review

Knowledge of slurry rheology in mineral processing is essential for the optimization of wet-grinding, dewatering, transport, and tailings management and it is becoming important in flotation due to the increasing need to process complex ores with a high clay mineral content. Slurries of these ores often display complex rheological behaviour even at low solids concentration, and traditional rheology measurements in mineral processing, such as yield stress and apparent viscosities, may not provide the critical information needed for process optimization. The objective of this paper is to provide a comprehensive review of some of the previous rheology studies performed at the bench, pilot plant, and industrial scale for different unit operations and to discuss the potential for alternative rheology measurements to provide a better insight into colloidal particle interactions in slurries with clay minerals. Firstly, the fundamentals of slurry rheology and the influence of colloidal particles are presented. Secondly, rheology measurements for suspensions are described briefly. Thirdly, a review of rheology studies in grinding, classification, flotation, dewatering, and tailings management is done, outlining possible ways of determining types of particle associations in slurries. Finally, recommendations for future research directions are provided.