Effect of slurry preconditioning on the occurrence of major minerals in the flotation products of coal

Abstract

ABSTRACT Organic and inorganic matters are two main compositions of coal, and their occurrence forms in flotation products are closely associated with the ultimate flotation performance. Considering that pulp-mixing stage can strongly affect particle surface properties, this study tentatively investigated the effect of slurry preconditioning on the element distribution of major minerals in flotation products of coal using a jet-flow mixer under various energy inputs. Measurements were obtained using X-ray diffraction, X-ray fluorescence, laser particle size analyzer, X-ray photoelectron spectroscopy, and a scanning electron microscope. The flotation results indicated that the optimal performance was obtained at 98.57 W/kg with a maximum combustible matter recovery (93.51%) and yield (85.56%). Throughout the flotation time, three variational stages of particle diameters were identified from relatively medium size to finer size and then to coarser size, corresponding to a progressive increase in the ash content of concentrates. Furthermore, the combined analyses of mineral phase and morphological characteristics revealed that kaolinite exhibited a higher removal rate than quartz in concentrates, for an appropriate conditioning intensity could detach fine slimes coating on coal surface but weakly influence the interlocked coal-mineral bodies. On the whole, an optimized preconditioning process could intensify the selective mineral migration to some extent.