Role of frothers in column flotation of coarse phosphates

Abstract

The use of column flotation has become increasingly popular. Although normally used for the flotation offline particles, column flotation was successfully used by the University of Florida for the flotation of phosphate from coarse feed (0.85 × 0.42 5-mm), fine feed (0.425 × 0.106-mm) and even unsized feed (0.85 × 0.106 mm). The application of frother in column flotation is essential to control the bubble size. In this paper, the role of frother type on the flotation of coarse Florida phosphate is highlighted. Two types of anionic and nonionic frothers were used. Statistical designs were used to determine the effects of collector dosage, frother concentration and pH, as well as the interactions between them. The results were then correlated with the measured air holdup and bubble diameter. The results show that, depending on the experimental conditions, concentrates containing from 24.71% to 31.21% P2O5 with recoveries of up to 96.1% can be obtained. The results indicate that frother type strongly affects phosphate recovery and concentrate grade. The interactions of the frother type, the concentration of collector and the pH are shown to play very important roles in determining the overall efficiency of column flotation in the recovery of coarse phosphate.