Used engine oil as flotation collector for the removal of unburned carbon from coal fly ash

The used engine oil as an alternative flotation collector for the removal of unburned carbon from coal fly ash was investigated. A Fourier-transform infrared spectroscopy analysis indicated that the C = O groups at 1706 cm(-1) were observed in the used engine oil, and the contact angle of coal fly ash increase to 41.01 degrees after treated by used engine oil. The loss on ignition of tailing ash had a minimum value of 2.51% when the dosage of used engine oil at 2000 g/t, with the recovery rate of unburned carbon was 82.19%. The cumulative unburned carbon recovery of 83.74% and flotation rate of -0.2359 s(-1) were obtained, and the results indicated that the first-order model with rectangular distribution was considered suitable for the data fitted of flotation kinetics. The reaction heat was decreased and the scanning electron microscope results showed a superior separation performance by the use of used engine oil. The utilization of used engine oil as flotation collector in the removal of unburned carbon from coal fly ash has an important practical significance for resource recycling and environmental conservation.