Volume 2, Issue 5, September 2014, Page: 59-64
Bauxite Enrichment by Microwave-Magnetising Roasting Using Sawdust as Reducing Agent
Grace Ofori-Sarpong, Mineral Engineering Department, University of Mines and Technology, Tarkwa, P. O. Box 237, Ghana
Charles Ebenezer Abbey, Mineral Engineering Department, University of Mines and Technology, Tarkwa, P. O. Box 237, Ghana
Richmond Komla Asamoah, Mineral Engineering Department, University of Mines and Technology, Tarkwa, P. O. Box 237, Ghana ; Ian Wark Research Institute, The ARC Special Research Centre for Particle and Material Interfaces, University of South Australia, Mawson Lakes, Adelaide, SA 5095, Australia
Richard Kwasi Amankwah, Mineral Engineering Department, University of Mines and Technology, Tarkwa, P. O. Box 237, Ghana
Received: Aug. 8, 2014;       Accepted: Aug. 22, 2014;       Published: Sep. 10, 2014
DOI: 10.11648/j.ajche.20140205.11      View  2593      Downloads  294
As high grade bauxite is getting depleted in several parts of the world, bauxite with high iron content is becoming increasingly important, and this trend has called for studies into the reduction of iron in bauxite. This study investigated the use of microwave energy in the magnetising roasting of high-iron bauxite using sawdust as reducing agent. Mineralogical studies revealed gibbsite and goethite as the main constituents of bauxite. The sawdust utilised had a fixed carbon content of 7.2% and ash, 1.7%. Microwave heating responses of bauxite and sawdust were determined as a function of mass and time, and both materials proved to be active microwave absorbers as they heated rapidly. Magnetising roasting of the bauxite sample was conducted with 20-40% sawdust at temperatures between 870oC and 880oC. After magnetic separation, the major phase in the magnetic fraction was magnetite, while gibbsite and boehmite were the major phases in the non-magnetic fraction. The alumina content of the non-magnetic fraction increased to 87.5% from an as-received sample grade of 53.6%. The use of sawdust in this manner satisfies a dual role of environmental clean-up and bauxite enrichment.
Bauxite, Sawdust, Microwaves, Magnetic Separation
To cite this article
Grace Ofori-Sarpong, Charles Ebenezer Abbey, Richmond Komla Asamoah, Richard Kwasi Amankwah, Bauxite Enrichment by Microwave-Magnetising Roasting Using Sawdust as Reducing Agent, American Journal of Chemical Engineering. Vol. 2, No. 5, 2014, pp. 59-64. doi: 10.11648/j.ajche.20140205.11
G. O. Kesse, The mineral and rock resources of Ghana. Balkema, A. A., Rotterdam, Netherlands, 1985. 610 pp.
F. A. Habashi,. Textbook of Hydrometallurgy. Métallurgie Extrative Québec, Canada 1999, 740 p.
R. Swain, L. N. Padhy, and R.Bhima Rao, Beneficiation studies on bauxite mining waste: a value addition for refractory industries. Iranian Journal of Materials Science and Engineering, 2011. Vol. 8 (3), pp. 37 – 49.
R. B. Rao, L. Besra, B. R. Reddy and G. N. Banerjee. The effect of pretreatment on magnetic separation of ferruginous minerals in bauxite. Magnetic Electrical Separation Journal, 1997, Vol. 8, pp. 115–123.
M. Autheir-Martin, G. Forté, S. Ostap and J. See. The mineralogy of bauxites for producing smelter-grade alumina. Journal of Materials, 2001, pp. 77-40.
C. A. Pickles, T. Lu, B. Chambers and J. Forster, A study of reduction and magnetic separation of iron from high iron bauxite ore. Canadian Metallurgical Quarterly 2012, Vol. 51 (4), pp. 424- 433.
E. Foley and K. Tittle, Removal of iron oxides from bauxitic ores. Proceedings of the Australian Institute of Mining and Metallurgy, 1971, Vol. 239, pp. 59–65.
P. Bolsaitis, V. Chang, H. Schorin and R. Aranguren, Beneficiation of ferruginous bauxites by high-gradient magnetic separation. International Journal of Mineral Processing, 1981. Vol. 8 (3), pp. 249-63.
G. Patermarakis and Y. Paspaliaris, The leaching of iron oxides in boehmitic bauxite by hydrochloric acid. Hydrometallurgy, 1989, Vol. 23 (1), pp. 77–90.
L. Y. Sadler and C. Venkataraman, A process for enhanced removal of iron from bauxite ores. International Journal of Mineral Processing, 1991. Vol. 31 (3-4), pp. 233-246.
Z. R. Vracar, S. M. Vukcevic, I. S. Parezanovic and Z. J. Kamberovic, The study of iron chlorination from bauxite for its enrichment. Scandinavian Journal of Metallurgy, 2001. Vol. 30 (2), pp. 84-90.
B. Mishra, A. Staley and D. Kirkpatrick, Recovery of value-added products from red mud. Minerals and Metallurgical Processing, 2002. Vol. 19 (2), pp. 87-94.
L. G. Shumskaya and T. S. Yusupov, Chemical processing of low-grade bauxites on the basis of activation grinding, Part I. Development of Defferization Method for Bauxites of the Bokson Deposit. Journal of Mining Science, 2003. Vol. 39 (5), pp. 508-513.
S. M. J. Koleini, M. Abdollahy, and R. Khormali, Iron removal from diasporic bauxite ore by acid leaching for bauxite beneficiation. Nashrieh Shimiva Mohandesi Shimi Iran, 2010. Vol. 28 (4), pp. 63–71.
G. N. Banerjee, B. R. Reddy, and R. B. Rao, Deironation of bauxite by gaseous reduction and magnetic separation for refractory uses. Transactions of the Indian Institute of Metals, 2000. Vol. 53 (4 and 5), pp. 527–529.
I. Szabo, A. Ujhidy, R. Jelinko, and R. I. Vassanyi, Decrease of iron content of bauxite through high-temperature chlorination. Hung. J. Indust. Chem., 1989. Vol. 17 (4), pp. 465–475.
J. D. Ford, and D. C. T. Pei, High Temperature Chemical Processing via Microwave Absorption. Journal of Microwave Power, 1967. Vol. 2 (2), pp. 61-64.
T. T. Chen, J. E. Dutrizac, K. E. Haque, W. Wyslouzil and S. Kashyap, Relative Transparency of Minerals to Microwave Radiation. Canadian Metallurgical Quarterly, 1984. Vol. 23 (3), pp. 349-351.
S. L. McGill and J. W. Walkiewicz, Application of Microwave Energy in Extractive Metallurgy. Journal of Microwave Power and Electromagnetic Energy, 1987. Vol. 22 (3), pp. 175-177.
J. W. Walkiewicz, G. Kazonich, and S. L. McGill, Microwave Heating Characteristics of Selected Minerals and Compounds. Minerals and Metallurgical Processing, 1988. Vol. 5 (1), pp. 39-42.
D. K. Xia, and C. A. Pickles, Applications of Microwave Energy in Extractive Metallurgy, a Review. CIM Bulletin, 1990. Vol. 90, pp. 96-107.
S. W. Kingman and N. A. Rowson, Microwave Treatment of Minerals – a Review. Minerals Engineering, 1998. Vol. 11 (11), pp. 1081-1087.
K. E. Haque, Microwave Energy for Mineral Treatment Processes – a Brief Review. International Journal of Mineral Processing, 1999. Vol. 57, pp. 1-24.
T. Lu, C.A. Pickles and S. Kelebek, Microwave heating behaviour of a gibbsite type bauxite ore," Symposium on Light Metals in Transport Applications Confernce of Metallurgists (CIM), , Toronto, ON, Edited by Bekguleryuz, M.O., Paray, F. and Wells, 2007. M 421-448.
ASTM, Standard Test Method for Ash in Pulp, Paper, and Paper Products1, ASTM International, 2002. 3pp.
K.V.N. S. Rao, Combustion studies of sawdust in a bubbling fluidized bed. The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering, 2007. pp. 945-952.
R. K. Amankwah, A. U. Khan, C. A. Pickles, and W. T. Yen, Improved grindability and gold liberation by microwave pretreatment of a free-milling gold ore. Mineral Processing and Extractive Metallurgy, IMM, Transactions 2005. C, 114, C30-C36.
C. A. Pickles, J. Mouris and R. M. Hutcheon, High-Temperature Dielectric Properties of Goethite from 400 to 3000 MHz. Journal of Materials Research 2005. Vol. 20 (1), pp. 18-29.
R. K. Amankwah and C. A. Pickles, Microwave calcination and sintering of manganese carbonate ore. Canadian Metallurgical Quarterly, 2005. Vol. 44(2), pp. 239-248.
H. D. Ruan, and R. J. Gilkes, Dehydroxylation of aluminous goethite: Unit cell dimensions, crystal size and surface area. Clays and Clay Minerals, 1995. Vol. 43 (2), pp. 196-211.
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