Modelling mineral slurreis using coupled discrete element method and smoothed particle hydrodynamics

Slurry in wet grinding mills is critical for transporting fine progenies out of the system to downstream floatation process. It is commonly modelled as Newtonian fluids when simulating grinding mills with numerical tools. However, rheology of the slurry exhibits shear thinning non-Newtonian behaviours. This study aims to investigate the non-Newtonian characteristics of mineral slurries both experimentally and numerically. Non-Newtonian smoothed particle hydrodynamics (SPH) and its coupling to discrete element modelling (DEM) framework was initially described. Non-Newtonian rheology of a copper slurry with various solids concentrations was determined experimentally by a rotary viscometer. SPH-DEM modelling of the viscometry test was conducted with both Newtonian and Power-law non-Newtonian settings in fluid phase, and comparisons were performed. Results suggested that the non-Newtonian SPH based method better reflects actual rheological behaviours of the slurry. In addition, DEM parameters exhibited limited impacts on rheology of the solids-liquid mixture, particularly at low solids concertation and high shear rate states. The findings suggested that the non-Newtonian based SPH-DEM method should be used to more accurately model the slurry flows within grinding mills.