Abstract
Coal-cleaning operations commonly produce a fine-waste stream containing a considerable amount of coal. The recovery of this coal is normally not economical because the coal is mixed with large amounts of difficult-to-remove clay slimes and is often heavily oxidized or contaminated. Conventional froth-flotation machines cannot, in a single flotation stage, produce an acceptable product from such material, and even flotation columns often have difficulty cleaning this type of feed.
A new type of flotation column was designed specifically to deal with these problems, and a column of this design was installed and tested in a coal-cleaning plant in Ohio. The feed coal tested was the plant’s tailings-thickener product. The coal was 80% −176 µm and had a heating value of 8401 Btu/lb. The coal contained 39.8% ash, as fine clay, and 2.83% total sulfur. Because previous attempts at conventional flotation of this type of material had been abandoned, plant personnel believed that the coal was too heavily oxidized and contaminated for flotation to be effective. However, by using the new column it was possible to recover up to 85% of the calorific value in a product containing <11% ash, and it was possible to recover 60% of the calorific value in a product containing <8% ash. In addition, the bulk of the pyritic sulfur was also rejected from the coal.
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SME Preprint 94–21, SME Annual Meeting, Feb. 14–17, 1994, Albuquerque, NM. M&MP paper 94–608.
Discussion of this peer-reviewed and approved paper is invited and must be submitted, in duplicate, prior to Nov. 31, 1995.
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Kawatra, S.K., Eisele, T.C. Baffled-column flotation of a coal plant fine-waste stream. Mining, Metallurgy & Exploration 12, 138–142 (1995). https://doi.org/10.1007/BF03403093
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DOI: https://doi.org/10.1007/BF03403093