Effect of surfactant type on the entrainment factor and selectivity of flotation at laboratory scale

• The entrainment factor is not unique, but depends on surfactant type.
• The surfactant has an effect, through water recovery and entrainment, on flotation selectivity.
• The grade-recovery curve can be shifted by changing the surfactant in the system.

In froth flotation, minerals report to the concentrate either by true flotation or entrainment. Previous research reported that flotation by entrainment is related to the amount of water that is transported to the concentrate (water recovery). On the other hand, plant operational experience indicates that frother type can be used to control the amount of water in the concentrate. In this work, a relationship between surfactant type and flotation by entrainment was obtained at laboratory scale using a batch flotation tests. The results indicate that the structure and molecular weight of surfactant influences the water reported to the concentrate, which is also related to the recovery of hydrophilic particles. The relationship between entrainment and water recovery is not unique, but depends on surfactant type. When comparing grade-recovery curves generated with different surfactants, the results show that there is an important effect of the surfactant type on the selectivity of the process.