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• Size-by-class flotation rate constants have been obtained from a liberation matrix. • Hydrophobic force has been used as a kinetic parameter for a flotation model. • The model can be used to predict grade vs. recovery curves from liberation data. • Copper recovery from a circulating load can increase both throughput and recovery. A large porphyry copper flotation plant has been simulated using a flotation model developed from first principles using the hydrophobic force as a kinetic parameter (Huang et al., 2022; Gupta et al., 2022). The input to the simulation was the size-by-class liberation matrix (m ij) of a flotation feed, which was essential for predicting the size-by-class flotation rate constants (k ij) and hence grade vs. recovery curves for the flotation bank. The model can be used to predict the performance of a flotation circuit provided that m ij matrices are available for the feeds to the flotation banks in the circuit. With limited information on feed characteristics, we carried out a circuit simulation of the plant with some simplifying assumptions. The results suggest that significant financial benefits can be gained by recovering the slow-floating particles from the cleaner-scavenger tails that constitute the circulating load using an advanced separation technology in a separate copper recovery unit. With this approach, it is possible to substantially increase the throughput while maintaining copper recoveries and concentrate grades. [ABSTRACT FROM AUTHOR]

A froth model has been developed from first principles to predict bubble coarsening and to better understand the complex mechanisms involved in froth stability. The model is based on predicting the kinetics of film thinning and the critical rupture thickness using the Reynolds lubrication theory and the capillary wave model, respectively. The macroscopic capillary pressure that drives initial film thinning has been corrected for the local capillary pressures in the menisci around the particles adsorbed in lamella films. It has been found that the latter varies with contact angle ( θ ) and particle size. At θ  < 90°, the local capillary pressure constitutes a resistance to film thinning, which in turn varies with particle loading. The model shows that a froth acquires a kinetic stability when film thinning slows down due to the presence of particles despite the negative disjoining pressures of the film segments that are free of particles. A series of flotation tests conducted with 35 μm glass spheres in the presence of 10 −5 M MIBC show that bubble coarsening as measured by the ratio between the bubble sizes at the top and bottom of a froth phase is minimum at θ  = 70°, which corresponds to the experimental data obtained in the present work and by others. The tests conducted with glass spheres with θ  = 40° show that bubble coarsening increases with particle size due to the high probability of particle detachment. Thus, the model is capable of predicting bubble coarsening in froth phase as functions of different physical, chemical, and operational variables. [ABSTRACT FROM AUTHOR]

• A flotation model has been validated against the rougher flotation circuit. • Hydrophobic force has been used as a kinetic parameter to predict product grades. • The model can predict the recovery vs. grade curves from liberation data. • The model can predict the size-by-size recovery curves. • Froth phase recovery is more sensitive to coarse particle recovery. A flotation model has been validated against the survey data obtained from a copper rougher flotation circuit with a circulating load. The model was developed using the hydrophobic force as a kinetic parameter, which made it possible to use the contact angles of the free and composite particles as input parameters so that the model can predict both recoveries and grades. The model also recognizes the role of bubble coarsening in determining the froth phase recoveries and grades. The model predictions are in good agreement with the survey data. The size-by-size recovery curve as predicted from the model shows an optimum particle size range that is consistent with most of the operating data reported in the literature. The model suggests that the upper particle size limit may be determined by the instability of the froth phase rather than the turbulence in the pulp phase of a flotation cell. [ABSTRACT FROM AUTHOR]

Flotation is a kinetic process designed to separate mineral fines by control of hydrophobicity. In general, both the recovery and selectivity of a flotation process increase with contact angle. It is difficult, however, to model flotation kinetics using the thermodynamic parameter. In the present work, we consider flotation as heterocoagulation so that the bubble-particle interactions occurring in the pulp phase of a flotation cell can be modeled using the hydrophobic force as a kinetic parameter that can represent the role of contact angles in flotation. The pulp-phase model developed in this manner has been combined with a froth-phase model developed earlier by considering the effect of particles in film thinning kinetics and bubble coarsening (Park et al, 2018). The combined model has been used to develop a flotation simulator that can be used to construct grade vs. recovery curves from feed characteristics (e.g., mineral liberation and particle size) and various operating parameters. The simulator has been tested successfully against a set of bench-scale continuous flotation test results reported in the literature (dos Santos and Galery, 2018). [ABSTRACT FROM AUTHOR]