Study on multi-component particle behaviour in a hydrocyclone classifier using experimental and computational fluid dynamics techniques

Abstract

Feed to the hydrocyclone classifier in mineral comminution circuit is comprised of a mixture of different size and density particles having various degrees of liberation can be termed as multi-component particulate system. In this study, an artificial mixture of silica and magnetite with different proportions is used for multi-component classification experiments in a 75 mm hydrocyclone. The effect of magnetite fraction on the separation efficiency of silica is analyzed experimentally. An interaction is observed between the components during the classification leading to an increased component cut-size and reduced component mass recoveries in the mixture compared to when it is classified individually. Numerical simulations are also carried out using the modified mixture multiphase model with additional shear lift, hindered settling drag law and slurry viscosity by solids and fines content. The comparison of simulated and experimental performance data is found to be in close agreement. At similar particle sizes, the heavier density component influences the lighter component by placing it away from the wall region and thereby a shift in the locus of zero vertical velocity towards the forced vortex. This results a significant increment in the lighter particle cut-size. Separation characteristics of the silica and magnetite particles are analyzed fundamentally using the equilibrium radius concept.