Experimental study on synergistic flotation of reclaimed coal by high-intensity conditioning and composite reagent

Abstract

China's coking coal scarcity and high clean coal prices make slime flotation economically vital, though reclaimed coal's severe oxidation poses major flotation challenges. Characterisation of Coal Slime from Xuehugou Coal Preparation Plant: coal slime has a high content of fine fractions, with the proportion of particles < 0.075 mm reaching 23.39%, and it is severely oxidised. The measured contact angle of the raw coal was only 32°, resulting in hydrophilicity and difficulties in floating. Traditional non-polar hydrocarbon collectors, such as kerosene and 2-octanol, were employed to scrub the surface of coal slime through high-intensity conditioning and then floated. Under the condition of identical clean coal ash content, the clean coal yield increased by 24.15%, and the combustible matter recovery increased by 26.65%. High-intensity conditioning at 12000 r/min for 20 min was identified as the optimal parameter set, achieving a clean coal yield of 67.38% with an ash content of 11.73%.