Recovery of carbon particles from coal tailings using flotation: case study of the Criciúma Coal Mine - Brazil

Abstract This study investigated the feasibility of recovering carbonaceous material from fine coal waste through the bench flotation process. The goal was to find an alternative for the disposal of these waste materials in tailings dams, which cause negative environmental impacts. The possibility of recovering carbonaceous material from fine coal waste through bench flotation was demonstrated. Tested were several combinations of reagents, the collectors Diesel, kerosene and Lilaflot, with concentrations ranging from 1000 to 6000g/t, and the frothers pine oil and MIBC, ranging from 100 to 600 g/t. The target of 40% mass recovery and ash content below 35% was achieved by three tested combinations, being the better result Diesel+MIBC, with concentrations of 6000 g/t + 400 g/t, and mass recovery of 42.2% and ash content of 33.5%. The desliming stage significantly contributed to improving the mass and carbonic recoveries, but it did not significantly improve the ash content results. The study showed potential to reduce the environmental impacts of the coal industry by decreasing the volume of waste disposed in tailings dams and minimizing the exposure of chemical elements that could lead to Acid Mine Drainage (AMD). Additionally, the recovery of carbonaceous material can produce a valuable product for use as fuel or in other applications.