Recycling Waste Polyurethane as a Carbon Resource in Ironmaking
Keywords:Polyurethane, Composite pellets, Infrared gas analyser, LECO carbon/sulphur analyser, LECO oxygen/nitrogen analyser, Extent of reduction
Globally, major avenues available for recycling waste polyurethane are disposal at landfill sites and incineration. However, polyurethane contains high levels of carbon and hydrogen that can be recovered for use as reductant in metal extraction processes. In this work we report the use of post-consumer polyurethane as reductant for the production of metallic iron from iron oxide in a horizontal tube furnace through the composite pellet approach. Composite pellets were formed from mixtures of iron oxide and post-consumer polyurethane. The iron oxide-polyurethane composites were heated from room temperature to 1200 Â°C and then between 1200-1600 Â°C in a continuous stream of pure argon and the off gas was analysed continuously using an infrared (IR) gas analyser. Elemental analyses of samples of the reduced metal were performed chemically for its oxygen content using a LECO oxygen/nitrogen analyser. The extent of reduction was then determined at two temperatures 1200 Â°C and 1550 Â°C. Gas emission studies revealed the emission of large volumes of the reductant gas CO along with CO2. It is further demonstrated that post-consumer polyurethane is effective at reducing iron oxide to produce metallic iron with complete reduction achieved in less than 4 min at 1550 Â°C.
Dankwah, J. R., Koshy, P., Saha-Chaudhury, N. M., O'Kane, P., Skidmore, C., Knights, D. and Sahajwalla, V. (2011), â€œReduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and Waste Plasticsâ€, ISIJ International, Vol. 51, No. 3, pp. 498-507.
Dankwah, J. R., Koshy, P., Oâ€™Kane, P. and Sahajwalla, V. (2012), â€œReduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and End-of-Life Tyresâ€, Steel Research International, Vol. 83, No.8, pp. 766-774.
Dankwah, J. R., Koshy P. and Sahajwalla, V. H. (2013), â€œReduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and End-of-Life Polyethylene Terephthalateâ€, Ironmaking and Steelmaking, Vol. 41, No. 6, pp. 401-409.
Dankwah, J.R., and Koshy, P. (2014), â€œReduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and Waste Polypropyleneâ€. High Temperature Materials and Processes, Vol. 33, No. 2, pp. 107-114.
Dankwah, J. R. and Baawuah, E. (2015), â€œRecycling Waste Bakelite as a Carbon Resource in Ironmakingâ€, International Journal of Scientific and Technology Research (IJSTR), Vol. 4, Issue 2, pp. 257-261.
Dankwah, J. R., Amoah, T., Dankwah, J. and Fosu, A. Y., (2015), â€œRecycling Mixed Plastics Waste as Reductant in Ironmakingâ€, Ghana Mining Journal, Vol. 15, No. 2, pp. 73-80.
Knacke, O., Kubaschewski, O., and Hasselmann,
K. (1991), Thermochemical Properties of
Inorganic Substances I, Springer Verlag, 2nd
Ed., 129 pp.
Kongkarat, S., Khanna, R., Koshy, P., Oâ€™Kane, P., and Sahajwalla, V. (2011), â€œUse of Waste Bakelite as a Raw Material Resource for Recarburization in Steelmaking Processesâ€ Steel Research International, Vol. 82(10), pp. 1228-1239.
Mansuri, I. A., Khanna, R., Rajarao, R. and Sahajwalla, V., (2013), â€œRecycling Waste CDs as Carbon Resource: Dissolution of Carbon into Molten Iron at 1550 Â°Câ€, ISIJ International, Vol. 53, No. 12, pp. 2259-2265.
Matsuda, T., Takekawa, M., Hasegawa, M., Ikemura, Y., Wakimoto, K., Ariyama, T., and Iwase, M. (2006), â€œUtilization of Waste Wood for Production of Iron, Carbon Monoxide and Hydrogen without Generating Carbon Dioxideâ€, Steel Res. Int., Vol. 77, pp. 774-784.
Matsuda, T., Hasegawa, M., Ikemura, A., Wakimoto, K., and Iwase, M. (2008), â€œUtilization of Waste Plastic for Production of Metallic Iron, Hydrogen and Carbon Monoxide without Generating Carbon Dioxideâ€, ISIJ Int., Vol. 48, No. 9, pp. 1186-1196.
Murakami, T., Akiyama, T. and Kasai, E., (2009), â€œReduction Behaviour of Hematite Composite containing Polyethylene and Graphite with Different Structures with Increasing Temperatureâ€, ISIJ Int., 49(6), pp. 809-814.
Murakami, T. and Kasai, E., (2011), â€œReduction Mechanism of Iron Oxide-carbon Composite with Polyethylene at Lower Temperatureâ€, ISIJ Int., 51(1), pp. 9-13.
Nath, D. C. D., Mansuri, I. A., Zaharia, M., Saha Chaudhury, N. and Sahajwalla, V., (2012), â€œRecycling End-of-Life Melamine at 1600 Â°C for Carbon Dissolution into Liquid Ironâ€, ISIJ International, Vol. 52, No. 5, pp. 922-927.
Nishioka, K., Taniguchi, T., Ueki, Y., Ohno, K., Maeda, T., and Shimizu, M. (2007), â€œGasification and Reduction Behaviour of Plastic and Iron Ore Mixtures by Microwave Heatingâ€, ISIJ Int., Vol. 47, No. 4, pp. 602-607.
Rajarao, R., Mansuri, I. A., Dhunna, R., Khanna, R. and Sahajwalla, V., (2014), â€œCharacterisation of Gas Evolution and Char Structural Change during Pyrolysis of Waste CDsâ€, Journal of Analytical and Applied Pyrolysis, Vol. 105, pp. 14-22.
Rajarao, R., Mansuri, I., Dhunna, R. and Sahajwalla, V., (2014), â€œStudy of Structural Evolution of Chars during Rapid Pyrolysis of Waste CDs at Different Temperaturesâ€, Fuel, Vol. 134, pp. 17-25.
Ueki, Y., Ohno, K., Maeda, T., Nishioka, K. and Shimizu, M. (2008), â€œReaction Behaviour during Heating Waste Plastic Materials and Iron Oxide Compositesâ€, ISIJ Int., Vol. 48, pp. 1670-1675.
Copyright Â© 2021 University of Mines and Technology (UMaT), Tarkwa. Ghana