Computer simulations of particle-bubble interactions using discrete element method

Abstract

Discrete Element Method computer simulations have been carried out to analyse the kinetics of collision of multiple particles against a central bubble whilst immersed in water. Two hundred particles, with diameters ranging between 24 and 66 mum, were randomly positioned within a maximum distance from the surface of a bubble of 2 mm in diameter. Initial particle velocities were random in direction and value and they followed Gaussian distributions with standard deviations of 1.0, 0.1 and 0.0. Two possible cases corresponding to relationships of the hydrophobic force with the distance between the particles and bubble have been analysed. In the first case the relationship had the form 1/d, whilst in the second case a relationship in the form 1/d2 was considered. The differences in the capture efficiency of the particles predicted by the two models were drastic. All particles were captured by the bubble in the first case for any distance smaller than 1 mm. However, only 60 % of the particles were captured in the second case even for distances smaller than 0.1 mm. This work provides simulation results that will aid in the future determination of a general hydrophobic force model, an approach of great importance to improve mineral separation using froth flotation