Which is Preferable for Coal Cleaning by Flotation: Pine Oil or MgCl2?

Abstract

Coal flotation using inorganic salts receives special attention. It utilizes coal hydrophobicity to float coal without adding collectors. Although different salts were tested, chloride salts are the most promising ones. However, the stabilization of froth layer using the salts only is dubious. Therefore, in this study, the flotation of coal was tested using either magnesium chloride or pine oil as a frother to see if there is a difference in coal flotation between these reagents in terms of ash removal and coal recovery in the float fraction. Additionally, both magnesium salt and pine oil were added together to clarify their interactive effect using statistical design. The results proved that the presence of either reagent (i.e., pine oil or MgCl2) is significant in reducing the ash content and increasing coal recovery. Using the MgCl2 only reduced the ash to less than 4.3% with a coal recovery up to 28% while adding 1.0 kg/t pine oil along with 4 kg/t MgCl2 enhanced the reduction of ash to less than 3% with a coal recovery of up to 80% at pH 2.