A simple model for the calculation of entrainment in flotation

Theoretical and experimental studies have been performed to analyze the entrainment of both hydrophilic and hydrophobic particles in flotation. A new model is proposed for the entrainment based on the water recovery trend. Two sets of timed flotation experiments were carried out to validate the model. These experiments were realized with quartz and pyrite as the only mineral in the pulp and with various frother concentrations and pulp densities. The chemical conditions of the pulp were adjusted to float pyrite as hydrophobic and to depress quartz as hydrophilic mineral. The solids recovery for each size fraction and water recovery was measured in these experiments. The proposed empirical model equation was checked against experimental observations. It was observed that the model equation well represented the entrainment-water relationship. Since hydrophilic mineral recovery mainly depends on the entrainment, the data obtained from quartz only tests were first fitted to the entrainment equation. The fit for quartz data was found to be satisfactory. This shows that the proposed model could be used to define the behavior of hydrophilic particles in a batch flotation test. The same model was applied for pyrite only tests and contribution of entrainment to hydrophobic mineral recovery was calculated. The results provided accurate interpretation of hydrophobic mineral entrainment, which is difficult to directly measure.