Abstract
The dispersion of oily collector has a significant effect on the flotation recovery of ultrafine coal. Generally, reagent dispersion is accomplished by mechanical mixing and/or ultrasonic agitation, followed by direct addition of dispersed collector into the flotation cell. Such dispersion and reagent addition techniques are invariably inadequate and nonselective. A new collector addition technique involving gas phase transport of atomized collector has shown improved results when compared to conventional reagent addition techniques. This technique involves atomization of the collector into the air stream. Under these circumstances, an aerosol is introduced into the flotation cell. Initially, the oil is dispersed within the air phase (continuous with respect to oil), and the air phase is dispersed within the pulp (continuous with respect to aerosol). In the flotation cell, the atomized oil droplets coalesce on the bubble’s surface and create a de facto oil-encapsulated bubble. This approach provides excellent dispersion, increases selectivity, and, most significantly, increases the flotation rate of ultrafine coal. Atomization of collector/frother combinations yielded improved flotation recovery and maintained near uniform froth levels, which is a desirable feature in coal flotation.
Microscopic examinations of the attachment of oil-coated bubbles at a coal surface were conducted by attachment time and contact angle measurements. Oil-coated bubbles attach at significantly faster rates and with a higher contact angle than oil-free bubbles.
Similar content being viewed by others
References
Aplan , F.F., 1976, “Coal Flotation,” Flotation, A.M. Gaudin Memorial Volume, M.C. Fuerstenau, ed., Vol. 2, SME-AIME, p. 1235.
Burkin, A.R., and Bramley, J.V., 1963, “Flotation with Insoluble Reagents. Effects of Surface-active Reagents on the Spreading of Oil at Coal Water Interfaces,” Journal of Applied Chemistry, Vol. 13, pp. 417–422.
Killmeyer, R.P., 1985, “Selective Agglomeration: Let’s Compare the Emerging Processes,” Coal Mining, September.
Laurel, M.J., 1985, “Five Advanced Cleaning Processes Bring Desulfurization Within Reach,” Coal Mining, September, p. 37.
Leonard, J.W., ed., 1979, Coal Preparation, AIME, New York.
Liu, Y.A., 1982, Physical Cleaning of Coal, Present and Developing Method, Marcel Dekker, Inc.
Miller, J.D., and Misra, M., 1985, “Carbon Dioxide Flotation of Fine Coal,” Coal Preparation, Vol. 2, No. 1.
Miller, J.D., and Van Camp, M.C., 1982, “Fine Coal Flotation in a Centrifugal Field With an Air Sparged Hydrocyclone,” Mining Engineering, November.
Moxon, N.T., and Keast-Jones, R., 1986, “The Effect of Collector Emulsification Using Non-Ionic Surfactants on the Flotation of Coarse Coal Particles,” International Journal of Mineral Processing, Vol. 18, p. 21.
Vincent, B., 1973, “The Van der Waals Attraction Between Colloid Particles Having Adsorbed Layers. Calculation of Interaction Curves,” Journal of Colloid and Interface Science, Vol. 42, No. 2, pp. 270–285.
Yoon, R.H., and Adel, G.T., 1984, “Preparation of Super Clean Coal,” US Dept. of Energy Technical Report.
Author information
Authors and Affiliations
Additional information
SME preprint 87–153, SME-AIME Annual Meeting, Denver, CO, February 1987. MMP paper 87–622. Discussion of this paper must be submitted, in duplicate, prior to Jan. 31, 1988.
Rights and permissions
About this article
Cite this article
Misra, M., Anazia, I. Ultrafine coal flotation by gas phase transport of atomized reagents. Mining, Metallurgy & Exploration 4, 233–236 (1987). https://doi.org/10.1007/BF03402698
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03402698