Final report on agglomerate column flotation for cleaning and desulfurization of Ohio coal fines

The objective of this research program was investigate the feasibility of cleaning and desulfurization of Ohio coal by an agglomerate column flotation process, which integrates selective flocculation with conventional column flotation. It was concluded earlier on in the program that the conventional design of flotation column was not particularly efficient for pyrite rejection. A novel design for flotation column system was conceived and a prototype unit was manufactured and tested in the laboratory. Several design and operational parameters for the column and the agglomerate flotation process were briefly investigated to define proper design and working conditions for a satisfactory performance. The novel design was compared with conventional design of flotation column through laboratory tests and through published results. The role of selective flocculation of coal including selective depression of pyrite has been identified and tested with both novel and conventional design of flotation columns. The results of these brief investigations, which are summarized in this report, suggest that: (1) excellent performance ca n be obtained with agglomerate column flotation using the new design. For example, a raw coal containing 3.16% total sulfur, 2.11% pyritic sulfur, and 17% ash can be cleaned to 1.91 % ash, 0.42% pyritic sulfur, 1.32% totalmore » sulfur, while maintaining a projected Btu/coal recovery of 86% (mmmf basis). This is equivalent to 89% ash removal and 81% pyritic sulfur (58% total sulfur) rejection. (2) The novel design of flotation column is superior to conventional design particularly for pyrite rejection.« less