Application of inclined channels in the hydrodynamic classification of minerals by particle size

Abstract

This study utilised a REFLUX™ Classifier, with water as the fluidising medium, to classify feed suspensions based on particle size. This work built on an earlier approach, known as Split Fluidisation, to achieve sharp separations, focussing on the potential to control the separation size, and to deliver efficient separations at high throughputs. The partition curves were remarkably sharp, with the Imperfection, I = Ep/D50, typically less than 0.14 for separation sizes covering a range from 182 µm down to 44 µm, with virtually no ultrafine entrainment with the coarse underflow, and virtually no oversize particles misplaced in the overflow. The solids throughputs ranged from 39 t/m2/h down to 8 t/m2/h. Importantly, the study achieved a deeper understanding of how to control the separation size, with the fluidisation velocity identified as the key control variable. The underflow rate is then increased to a level sufficient to prevent the bed level from rising, while ensuring the solids throughput is below the limit applicable for a given separation size.