The joint effect of rank and grain size on the flotation of Australian bituminous coals

Abstract

Laboratory batch flotation tests were carried out to determine the effect of grain size on the recovery of four Australian bituminous coals of high and low rank. The flotation concentrates, taken over successive time intervals, and the tailings, were sized and the recovery-size curves plotted. A method was developed for determining the proportions of liberated and composite grains in the various flotation products. Flotation tests were carried out in the presence of methylisobutylcarbinol (MIBC) and MIBC + kerosene. The shapes of the recovery-size curves depended on the rank of the coal and whether or not kerosene was present. The variation of the recovery with size was explained in terms of the joint effect of rank and size on the floatability of composite grains.