Influence of particle size and contact angle on the flotation of chalcopyrite in a laboratory batch flotation cell

The flotation response of chalcopyrite has been characterized as a function of particle size and advancing contact angle. The advancing contact angle of individual particle size fractions was controlled to different values. Flotation experiments were carried out under constant hydrodynamics and feed particle size distribution. A two-component kinetic model was used to fit the experimental flotation data. The maximum recovery increased with advancing contact angle for each size fraction. Particles within the same size fraction and within the same contact angle range displayed similar flotation behaviour, within experimental error, in different tests. Evidence of a distribution of advancing contact angle values within each particle size fraction was found, and it was assumed that particles in the non-floating fraction had advancing contact angle values below the critical contact angle required for stable bubble-particle attachment. The flotation results were used to model the maximum recovery and the critical contact angle as a function of particle size, assuming a statistical distribution of contact angle values about a measured mean. The recovery and rate constant data were collated into master curves as a function of particle size for different contact angle ranges. These master curves, together with the critical contact angle, may be used to benchmark the flotation response of chalcopyrite and to infer an effective operational contact angle in natural ores.

Research Highlights
► Variation of contact angle with particle size for similarly treated chalcopyrite particles.
► Particles within different size fractions apparently float independently of each other.
► Distribution of contact angles gives rise to differences in flotation behaviour.
► Critical contact angle for floatability of mineral particles varies with the particle size fraction.