Investigating the Effect of Zero Prewetting Time on Rougher Flotation of Coal Tailings

The beneficiation of coal tailings is usually difficult by common oily collectors in the flotation process, so it is necessary to use a suitable method for clean coal recovery from coal tailing dams. Thus, this study was aimed to investigate the behavior of dissolved air flotation by zero prewetting time for the clean coal recovery and to optimize the conditions of zero prewetting time for an effective flotation. In this regards, the effects of the process parameters, i.e., pH, frother type, collector type on the rougher flotation recovery of coal tailings were assessed and optimized. Additionally, Fourier transform infrared (FTIR) spectroscopy was used to understand the functional groups of oily collectors on the surface of floated products. The findings indicated that the frother type and the interactive effects between the type of frother and collector had the most effect on the performance of flotation. It was also found that under the optimal conditions (150 g/t Methyl isobutyl carbinol, 1500 g/t gas oil, and pH 4), the combustible recovery, yield reduction factor, and flotation efficiency index of coal reached to 67.79%, 0.056%, and 37%, respectively. Meanwhile, the FTIR analysis confirmed that the less adsorption of gas oil collector occurred in the presence of SDS (Sodium dodecyl sulfate) as frother due to the interaction of SDS and collectors