Upgrading Coal Using a Pneumatic Density-Based Separator

Abstract

The potential of dry cleaning coal of varying ranks using a pneumatic table concentrator has been evaluated as part of an ongoing investigation. The evaluation has been performed at several sites throughout the United States where coal is extracted from surface open cast, highwall and underground operations as well as from coarse reject. The treated coals varied in feed ash content (i.e., 7–70%). Regardless of the mineral matter type, pure rock removal into the reject stream was achieved in all applications with little coal loss. Field data obtained when treating 50 × 6 mm run-of-mine bituminous coal indicate that 70–90% of the >2.0 Relative Density (RD) rock can be rejected. As a result, a clean product having acceptable market quality was generated from several coal sources including lignite, sub-bituminous, and bituminous coals. This article provides an overview of data from recent field testing of the dry air table technology and discusses the potential implementation strategy for the various sites evaluated.