Effect of frother on dynamic detachment of rising bubble-coarse particle aggregates at gas-liquid interface

Abstract

In the flotation process, the bubble-coarse particle aggregates easily undergo detachment at the gas-liquid interface, resulting in low mineral recovery. This paper tested the variation rule of surface tension with a concentration in the solution of four alcohols frother, namely, n-pentanol (NPA), methyl isobutyl carbinol (MIBC), 2-octanol, and polypropylene glycol (PPG). The effects of frothers on the motion characteristics of rising bubble-coarse particle aggregates and the dynamic detachment of aggregates at the gas-liquid interface were investigated separately using a high-speed dynamic camera system and a dynamic detachment device. The results showed that the solution surface tension decreased and then tended to be stabilized with the increase of frother concentration. Under the same concentration, the stronger the surface activity of the frother, the smaller the rising velocity of the bubble-coarse particle aggregates, and the more stable the motion state of the aggregates, with a smaller velocity fluctuation. The lower rising velocity reduced the particle detachment probability when aggregates collided with the gas-liquid interface. The merger time of the bubble-coarse particle aggregates was extended with the improved surface activity of the frother, increasing by more than 1 s compared to the solution without the frother. The study will contribute to effectively reduce the dynamic detachment probability of bubbles-coarse particle aggregates at the gas-liquid interface by selecting the type and concentration of frothers, meanwhile optimizing the reagent regime to enhance the coarse particle flotation recovery in the practical production process.