Abstract
This study was carried out to understand the impact of variation in material morphology on the efficacy of microwave pretreatment. Three different types of mineral matter — coal, iron ore and manganese ore — were treated with microwaves at different energy levels, from 180 to 900 W, for different time durations of one to five minutes. The treated samples were subjected to microscopic, milling and liberation studies. Coal is a porous and amorphous material with low dielectric constant, and grinding of the microwave-pretreated coal samples resulted in an 18.18 percent reduction in the 80 percent of passing particle size, or d80, and a 17.1 percent increase in carbon recovery. The microwave-pretreated soft and friable manganese ore samples showed a 47.82 percent reduction in d80 during grinding and higher manganese recovery of 42.46 percent during liberation analysis. The microwave pretreatment and milling of hard and banded iron ore reduced the d80 by 20.83 percent, but no improvement was observed in mineral liberation. Coal showed better results during treatment at lower energy levels of 180 W for one to three minutes, whereas the minerals needed higher energy of 900 W for five minutes. Particle size analysis indicated rapid size reduction up to an energy input of 25 Wh. This effect diminished with increased energy input.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barani, K., Koleini, S.M.J., Rezai, B., and Khodadadi, A., 2012, “The Effect of Sample Geometry and Placement of Sample on Microwave Processing of Iron Ore,” International Journal of Applied Physics and Mathematics, Vol. 2, No. 2, pp. 131–134, https://doi.org/10.7763/ijapm.2012.v2.68.
Batchelor, A.R., Jones, D.A., Plint, S., Kingman, S.W., 2015, “Deriving the ideal ore texture for microwave treatment of metalliferous ores,” Minerals Engineering, Vol. 84, pp. 116–129, https://doi.org/10.1016/j.mineng.2015.10.007
Bermúdez, J.M., Beneroso, D., Rey-Raap, N., Arenillas, A., and Menéndez, J.A., 2015, “Energy consumption estimation in the scaling-up of microwave heating processes,” Chemical Engineering and Processing: Process Intensification, Vol. 95, pp. 1–8, https://doi.org/10.1016/j.cep.2015.05.001.
Borah, R.C., Ghosh, P, and Rao, PG., 2011, “A review on devolatilization of coal in fluidized bed,” International Journal Energy Resources, Vol. 35, pp. 929–963, https://doi.org/10.1002/er.1833.
Chandrasekaran, S., Ramanathan, S., and Basak, T, 2013, “Microwave food processing — A review,” Food Research International, Vol. 52, No. 1, pp. 243–261, https://doi.org/10.1016/j.foodres.2013.02.033.
Chen, TT, Dutrizac, J.E., Haque, K.E., Wyslouzil, W., and Kashyap, S., 1984, “The relative transparency of minerals to microwave radiation,” Canadian Metallurgical Quarterly, Vol. 23, No. 3, pp. 349–351, https://doi.org/10.1179/cmq.1984.23.3.349.
Clark, D.E., and Sutton, W.H., 1996, “Microwave processing of materials,” Annual Review of Materials Science, Vol. 26, pp. 299–331.
Faria, G.L., Jannotti, N., and da Silva Araüjo, FG., 2012, “Decrepitation behavior of manganese lump ores,” International Journal of Mineral Processing, Vol. 102–103, pp. 150–155, https://doi.org/10.1016/j.minpro.2011.10.004.
Gaete-Garreton, L.F, Vargas-Hermandez, YP, and Velasquez-Lambert, C., 2000, “Application of ultrasound in comminution,” Ultrasonics, Vol. 38, No. 1–8,pp. 345–352, https://doi.org/10.1016/s0041-624x(99)00170-5.
Hartlieb, P., Toifl, M., Kuchar, F, Meisels, R., and Antretter, T., 2016, “Thermophysical properties of selected hard rocks and their relation to microwave-assisted comminution,” Minerals Engineering, Vol. 91, pp. 34–41, https://doi.org/10.1016/j.mineng.2015.11.008.
Harrison, P.C., and Rowson, N.A., 1996, “The effect of heat treatment on the grindability of coals,” The 1996 ICHEME Research Event: The Second European Conference.
Harrison, P.C., and Rowson, N.A., 1997, “The effect of microwave and conventional heat treatment on the comminution of coal,” IChemE Research Event, Vol. 1, pp. 33–36.
Kim, K.J., and Ahn, H.G., 2012, “The effect of pore structure of zeolite on the adsorption of VOCs and their desorption properties by microwave heating,” Microporous and Mesoporous Materials, Vol. 152, pp. 78–83, https://doi.org/10.1016/j.micromeso.2011.11.051.
Kingman, S.W., and Rowson, N.A., 1998, “Microwave treatment of minerals — A Review,” Minerals Engineering, Vol. 11, No. 11, pp. 1081–1087, https://doi.org/10.1016/s0892-6875(98)00094-6.
Klimpel, R.R., and Austin, L.G., 1982, “Chemical additives for wet grinding of minerals,” Powder Technology, Vol. 31, No. 2, pp. 239–253, https://doi.org/10.1016/0032-5910(82)89012-8.
Kumar, P, Sahoo, B.K., De, S., Kar, D.D., Chakraborty, S., and Meikap, B.C., 2010, “Iron ore grindability improvement by microwave pretreatment,” Journal of Industrial and Engineering Chemistry, Vol. 16, No. 5, pp. 805–812, https://doi.org/10.1016/j.jiec.2010.05.008.
Li, H., Lin, B., Yang, W., Zheng, C., Hong, Y, Gao, Y, Liu, T, Wu, S., 2016, “Experimental study on the petrophysical variation of different rank coals with microwave treatment,” International Journal of Coal Geology, Vol. 154–155, pp. 82–91, https://doi.org/10.1016/j.coal.2015.12.010.
Lester, E., and Kingman, S., 2004, “The effect of microwave pre-heating on five different coals,” Fuel,Vol. 83, No. 14–15, pp. 1941–1947, https://doi.org/10.1016/j.fuel.2004.05.006.
Lovas, M., Kovácová, M., Dimitrakis, G., Cuvanová, S., Znamenácková, I., and Jakabský, S., 2010, “Modeling of microwave heating of andesite and minerals,” International Journal of Heat and Mass Transfer, Vol. 53, No. 17–18,pp. 3387–3393, https://doi.org/10.1016/j.ijheatmasstransfer.2010.03.012.
McGill, S.L., Walkiewicz, J.W., and Smyres, G.A., 1988, “The effects of power level on microwave heating of selected chemicals and minerals,” Materials Research Society Proceedings, Vol. 124, pp. 247–252, https://doi.org/10.1557/proc-124-247.
Menezes R.R., Souto P.M., and Kiminami, R.H.G.A., 2012, “Microwave fast sintering of ceramic materials,” Sintering of Ceramics — New Emerging Techniques, A. Lakshmanan, ed., InTechOpen, Rijeka, Croatia, https://doi.org/10.5772/34181.
Mondal, A., Shukla, A., Upadhyaya, A., and Agrawal, D., 2010, “Effect of porosity and particle size on microwave heating of copper,” Science of Sintering, Vol. 42, No. 2, pp.169–182.
Norgate, T.E., and Weller, K.R., 1994, “Selection and operation of high pressure grinding rolls circuits for minimum energy consumption,” Minerals Engineering, Vol. 7, No. 10, pp. 1253–1267, https://doi.org/10.1016/0892-6875(94)90116-3.
Singh, V., Tathavadkar, V., Denys, M.B., and Venugopal, R., 2012, “Application of quartz inversion phenomenon in mineral processing — A case study of siliceous manganese ores,” Minerals Engineering, Vol. 32, pp. 8–11, https://doi.org/10.1016/j.mineng.2012.03.010.
Speight, J.G., 2005, Handbook of Coal Analysis, John Wiley & Sons, Hoboken, NJ, https://doi.org/10.1002/0471718513.
Telford, W.M., Geldart, L.P., and Sheriff, R.E., 1990, Applied Geophysics, Cambridge University Press, pp. 285–286, https://doi.org/10.1017/cbo9781139167932.
Viswanathan, M., 1990, “Investigations on the effect of microwave pretreatment on comminution/beneficiation and desulphurization of coals,” 11th International Coal Preparation Congress, oct. 22–25, 1990, Tokyo, Japan.
Wang, E., Shi, F, and Manlapig, E., 2011, “Pre-weakening of mineral ores by high voltage pulses,” Minerals Engineering, Vol. 24, No. 5, pp. 455–462, https://doi.org/10.1016/j.mineng.2010.12.011.
Walkiewicz, J.W., Clark, A.E., and McGill, S.L., 1991, “Microwave-assisted grinding,” IEEE Transactions on Industry Applications, Vol. 27, No. 2, pp. 239, https://doi.org/10.1109/28.73604.
Wilson, M.P., Balmer, L., Given, M.J., MacGregor, S.J., Mackersie, J.W., and Timoshkin, I.V., 2006, “Application of electric spark generated high power ultrasound to recover ferrous and non-ferrous metals from slag waste,” Minerals Engineering, Vol. 19, No. 5, pp. 491–499, https://doi.org/10.1016/j.mineng.2005.08.017.
Author information
Authors and Affiliations
Corresponding author
Additional information
Paper number MMP-16-084.
Discussion of this peer-reviewed and approved paper is invited and must be submitted to SME Publications Dept. prior to Nov. 30, 2017.
Rights and permissions
About this article
Cite this article
Singh, V., Venugopal, R., Tripathy, S.K. et al. Comparative analysis of the effect of microwave pretreatment on the milling and liberation characteristics of mineral matters of different morphologies. Mining, Metallurgy & Exploration 34, 65–75 (2017). https://doi.org/10.19150/mmp.7506
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.19150/mmp.7506