New approaches to dewatering of suspensions in the minerals industry

The performance of dewatering processes such as thickening has been predicted by applying modern dewatering theory which properly accounts for compression of the suspension network structure. The method involves the characterisation of the variation in compressibility and permeability of a feed slurry over the relevant concentration range, from the feed solids concentration to the output solids concentration. These material properties are then used in thickener dewatering models to predict performance for a range of operating conditions. The role of shear in causing enhancement of dewatering that would not normally be accounted for in simple laboratory tests has now been quantified. A critical shear rate above which shear enhanced dewatering is diminished has also been identified and the incorporation of these effects into the phenomenological dewatering models has now demonstrated better confluence of model predictions and full scale thickener performance.