Effects of attrition on coarse coal flotation in the absence of collectors

Abstract

Samples of clean coarse coal particles (0.5–0.25mm) were used and the flotation process was conducted in the absence of collectors. Scanning electron microscope with energy dispersive spectrometer (SEM/EDS) was used to indicate the elementary composition on coal particle surface as well as particle shape. The attrition process was conducted in a flotation cell with a varied period of stirring process prior to the flotation process. Throughout this paper, it was found that the content of carbon element on coarse coal surface was reduced after attrition whereas the contents of aluminium and silicon elements were increased. A small part of organic matters could release from coarse coal surface by attrition. The attrition process rounded the edges of the coal particles. The flotation performance of coarse coal particles with round corner was worse than that of coal particles with sharp corner. A long period of attrition process could be conducive to obtain a low ash concentrate.