Study of the mechanism of fine coal beneficiation in air table

Beneficiation of fine (-1.0 mm) coal in air table was studied both from theoretical and experimental angles. Experiments were performed according to Response Surface Method with high ash (43%) coal fines using air table. The features of separation were established and favorable operating regimes identified for the targeted product. About 10% (absolute) reduction in the ash level was achieved in single stage operation with a reasonably high product yield. Separation in air table was described by a set of mathematical equations. It was established that the vertical stratification and horizontal segregation are the two phenomena responsible for separation. Both these phenomena are described mathematically from a fundamental standpoint using force balance approach. Simulation performed using the model equations led to the identification of the trajectories of various particles with different size and density over the deck surface. Following the trajectories and using the size and density distribution of the coal particles the mass yield and the ash level of the product are computed. The computed data and the experimental observations were found to be in good agreement. (C) 2015 Elsevier Ltd. All rights reserved.