Enhancing lignite flotation performance by mechanical thermal expression treatment

Abstract

ABSTRACTThe developed pore distribution and large amount of oxygen functional groups have a detrimental effect on lignite flotation. The effect of mechanical thermal expression treatment (MTET) on lignite flotation performance was investigated in this study. The pore distribution and functional groups of the lignite before and after MTET were analyzed using static nitrogen adsorption method, mercury intrusion porosimetry, and Fourier transform infrared (FTIR) spectroscopy. The results showed that the clean coal yield after MTET at the 9 MPa and 200°C condition was 21.11% higher than that of untreated coal under the same flotation conditions. Both hydrophilic oxygen functional groups and porosity of the lignite decreased after MTET, increasing the absorption efficiency of oil collector on the lignite surface and the probability of bubble–particle attachment. The results of this study are expected to provide a basic understanding of the effect of MTET on lignite flotation.