Abstract
The selective depression of pyrite from the Kentucky No. 9 coal seam was systematically examined using various kinds of inorganic and organic chemicals. Most of the organic chemicals tested showed little selectivity in pyrite depression. It was found that both orthophosphate and pyrophosphate were effective for the selective depression of coal pyrite in coal flotation using fuel oil as a collector. At substantially low concentrations of pyrophosphate, the flotation of coal pyrite was completely depressed over a wide pH range, while the coal flotation remained unaffected. The mechanism of the selective depression of pyrite by phosphates was explained with the help of thermodynamic calculations of iron-phosphate-water systems and zeta-potential measurements. It was shown that pyrophosphate reacts strongly with the iron ions of pyrite to form stable hydrophilic iron pyrophosphate complexes on pyrite surfaces.
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Aplan, F.F., and Arnold, B.J., 1991, “Flotation,” Coal Preparation, 5th Ed., J.W. Leonard ed., SME, Littleton, CO, pp. 450–485.
Arnold, B.J., and Aplan, F.F., 1986, “The effect of clay slimes on coal flotation, Part I: The nature of the clay,” International Journal of Mineral Processing, Vol. 17, pp. 225–242.
Arnold, B.J., and Aplan, F.F., 1990, “The use of pyrite depressants to reduce the sulfur content of Upper Freeport seam coal,” 3rd International Conference on Processing and Utilization of High Sulfur Coal, T. D. Wheelock and R. Markuszewski, eds., Elsevier, Amsterdam, pp. 171–185.
Choudhry, V., and Aplan, F.F., 1992, “Pyrite depression during coal flotation, Part 1: Inorganic ions,” Minerals and Metallurgical Processing, May, pp. 51–56.
Eriksson, G., 1979, “An algorithm for the computation of aqueous multicomponent, multiphase equilibria,” Analytica Chimica Acta, Vol. 112, pp. 375–383.
Firth, B.A., and Nicol, S.K., 1984, “The effect of oxidized pyritic sulfur on coal flotation,” Coal Preparation, Vol. 1, pp. 53–70.
Fornasiero, D., and Ralston, J., 1992a, “Interaction of ethyl xanthate with pyrite,” Electrochemistry in Mineral and Metal Processing III, R. Woods and P.E. Richardson, eds., The Electrochemical Society, Inc., Pennington, N.J., pp. 191–220.
Fornasiero, D., and Ralston, J., 1992b, “Iron hydroxide complexes and their influence on the Interaction between ethyl xanthate and pyrite,” Journal of Colloid and Interface Science, Vol. 151, pp. 225–235.
Hogfeldt, E., 1982, Stability Constants of Metal-Ion Complexes, Part A: Inorganic Ligands, Pergamon Press.
Jiang, C.L., 1993, “A Study of the Interfacial Chemistry of Coal and Pyrites Using Flotation,” M.S. thesis, University of Kentucky, Lexington, KY, 180 pp.
Miller, F.G., 1964, “Reduction of sulfur in minus 28-mesh bituminous coal,” Transactions, AIME, Vol. 229, pp. 7–15.
Parekh, B.K., 1979, “The Role of Hydrolyzed Metal Ions in Charge Reversal and Flocculation Phenomena.” Ph.D. Thesis. Pennsylvania State University. State College. PA.
Perry. R.W., and Aplan. F.F., 1985. “Polysaccharides and xanthated polysaccharides as pyrite depressant during coal flotation.” Processing and Utilization of High Sulfur Coals. Y.A. Attia. ed., Elsevier, New York, pp. 215–238.
Plouf, T.M., 1980, “Froth flotation techniques reduce sulfur and ash,” Mining Engineering, Vol. 32, No. 8. pp. 1220–1223.
Raleigh, C.E., and Aplan. F.F., 1991, “The effect of feed particle size and reagents on coal mineral matter selectivity during the flotation of bituminous coals,” Minerals and Metallurgical Processing. Vol. 8. pp. 82–90.
Rao. T.C., 1988. “Recent advances in fine coal beneficiation.” Minerals and Metallurgical Processing. August, pp. 124–132.
Sillen, L.G., and Martell, A.E., 1964, “Stability Constants of Metal-Ion Complexes,” The Chemical Society. Special Publication No. 17, London.
Sillen, L.G., and Martell, A.E., 1970, “Stability Constants of Metal-Ion Complexes,” The Chemical Society, Special Publication No. 25, London.
Smith, R.W., and Martell, A.E., 1979, Critical Stability Constants, Vol. 4, Inorganic Ligands, New York, Plenum Press.
Stumm, W., and Morgan, J.J., 1981, Aquatic Chemistry. Wiley and Sons, New York.
Wang, X., and Forssberg, K.S.E., 1991, “EDTA-induced flotation of sulfide minerals,” Journal of Colloid and Interface Science, Vol. 140, No. 1, pp. 217–226.
Wang, X., and Forssberg, K.S.E., 1991, “Mechanisms of pyrite flotation with xanthates,” International Journal of Mineral Processing, Vol. 33, pp. 275–290.
Xu, D.D., and Aplan, F.F., 1994, “Joint use of metal ion hydroxy complexes and organic polymers to depress pyrite and ash during coal flotation,” Minerals and Metallurgical Processing. Vol. 11, No. 11, pp. 223–230.
Yancey, H.F., and Taylor, J.A., 1935, “Froth Flotation of Coal; Sulfur and Ash Reduction,” US Bureau of Mines, Report of Investigations 3263, pp. 1–24.
Yoon, R.H., Lagno, M.L., Luttrell, G.H., and Mielczarski, J.A., 1991, “On the hydrophobicity of coal pyrite,” in Proceeding and Utilization of High Sulfur Coals IV, P.R. Bugan, D.R. Quigley and Y.A. Attia, eds., Elsevier, Amsterdam, pp. 241–253.
Zimmerman, R.E., 1948, “Flotation of bituminous coal,” Transactions, AIME, Vol. 177, pp. 338–356.
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Nonmeeting paper 97-308
Discussion of this peer-reviewed and approved paper is invited and must be submitted to SME prior to May 31, 1998.
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Jiang, C.L., Wang, X.H., Parekh, B.K. et al. Pyrite depression by phosphates in coal flotation. Mining, Metallurgy & Exploration 15, 1–7 (1998). https://doi.org/10.1007/BF03402779
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DOI: https://doi.org/10.1007/BF03402779