Dense-medium cycloning of fine coal refuse material

Laboratory testing was carried out to evaluate the performance of a dense-medium cyclone for treating fine coal refuse. The tested material was obtained from the feed stream to a water-only cyclone circuit treating nominal -0.6mm bituminous coal refuse material obtained from an existing waste pile. A 76.2 mm (3 in) diameter cyclone was used for all tests, which were carried out at three medium relative densities, with and without ultrasonic treatment. Fractional recovery (partition) curves were generated for several size fractions (g) from which the characteristic performance parameters (relative density of separation and probable error) were determined. In addition, the corresponding magnetite size selectivity parameters (cut size, sharpness index, and apparent bypass) were also determined. The results indicated that the dense-medium cyclone was capable of cleaning down to 0.037mm. Ultrasonic treatment appeared to have only minimal impact on the overall separation of the coal and magnetite.