Application of the Falcon Concentrator for fine coal cleaning

An enhanced gravity separator (EGS) commercially known as the Falcon Concentrator has been evaluated for its ability to treat fine coal. From a comparison with other EGS technologies, the magnitude of the applied centrifugal force was found to determine the overall separation performance and throughput capacity. Using the relatively high g-forces supplied by a continuous 25-cm diameter Falcon unit, a low density cut point of 1.6 was achieved for the 210 × 37 μm size fraction of a fine coal sample which is significantly lower than that achieved by other EGS units. As a result, ash rejection values between 60% to 75% have been obtained from the treatment of several fine coal samples while recovering greater than 85% of the combustibles, which corresponds to an organic efficiency of about 90%. In addition, the sulfur rejection values achieved on various particle size fractions comprising a -1 mm coal sample were superior to that achieved by a spiral concentrator and a flotation column. Due to an insufficient centrifugal force, the metallurgical performances achieved on the basis of ash rejection for the -37 μm size fraction of all coal samples were insignificant. The ability to achieve efficient, low gravity cut points on fine coal and the operational simplicity of the Falcon Concentrator indicate potential for near term application in coal processing plants.