Factors affecting the kinetics of froth flotation
In this research work, three types of flotation models (discrete, mean rate and the gamma function models) are modified based on the relationship between mass recovery and recovery. The modified models can be used to calculate both the recovery and grade of concentrate. Experimental work was carried out by using three different samples, which are chalcopyrite, coal and complex sulphide. In the chalcopyrite and coal flotation, air flow rate (AFR) was varied and different size fractions were considered in coal flotation. In complex sulphide flotation, the impeller speed (IPS) and air flow rate were varied, different size fractions were also considered individually. From the experimental results, the effect of air flow rate, impeller speed and particle size on the recovery and grade of concentrate are obtained, it is shown that an increase in air flow rate does not significantly increase recovery but reduce the grade of concentrate. High impeller speed can increase the recovery of fine and medium size, but it has very little effect on the coarse size. The effect of particle is that the medium size has the highest recovery in Fe minerals but the fine has the highest recovery in Zn and Cu minerals. The air flow rate, impeller speed and particle size affect on the kinetics of flotation is discussed from the model results. Where the modified models are used, the results show that an increase in air flow rate will increase the flotation rate of all size fraction, but an increase in impeller speed can only increase the flotation rate of the fine and medium size. The medium size has the highest flotation rate in most of the case.