Recycling Waste Electrical Socket as a Carbon Resource in Ironmaking

Abstract

Globally, millions of waste electrical sockets (WES) are generated annually. This category of waste material is difficult to recycle because they are thermosetting polymers which cannot be remoulded after setting. In this work, the reduction of medium grade Agbaja iron ore from Nigeria, by carbonaceous materials generated from WES was investigated through experiments conducted in a domestic microwave oven. Composite pellets of medium grade Agbaja iron ore (assaying ~74 % Fe 2 O 3 ) with WES were irradiated in a domestic microwave oven (Pioneer, Model PM-25 L, 2450 MHz and 1000 W). The reduced mass was characterised by XRD and SEM/EDS analyses and the extent of reduction after 40 min was determined. SEM/EDS analysis revealed a highly reduced mass with distinct peaks of elemental iron and this was corroborated by XRD analyses that confirmed the formation of metallic iron. The extent of reduction obtained after using WES as reductant was over 80%. Accordingly, carbonaceous materials generated from waste electrical sockets are effective reductants for producing metallic iron from the Agbaja iron ore.

Production of Iron Nuggets from the Akpafu-Todzi Iron Ore and Artisanal Ferrous Slag using Post Consumer Thermosets (Waste Electrical Sockets) as Reductants

“…Some research investigations have been conducted on utilisation of postconsumer plastics as reductants or as a source of energy in the metallurgical field (Matsuda et al, 2006;Nishioka et al, 2007;Matsuda et al, 2008;Ueki et al, 2008;Dankwah et al, 2011;Kongkarat et al, 2011;Murakami et al, 2009;Murakami and Kasai, 2011;Dankwah et al, 2012;Dankwah et al, 2013;Dankwah and Koshy, 2014;Dankwah et al, 2015a;Dankwah et al, 2015b). A review of these investigations shows that thermoplastic polymers and or their blends with metallurgical coke, graphite, or biomass are the dominant reductants often used for the production of metallic iron from reagent grade iron oxides or electric arc furnace (EAF) slags containing iron oxide (Dankwah et al, 2016). In addition to the above polymers and their blends, other researchers have utilised elastomers and thermosetting plastics as reductants (Dankwah et al, 2012, Mansuri et al, 2013, Rajarao et al, 2014a, Rajarao et al, 2014b, Nath et al, 2012, Dhunna et al, 2014and Dankwah and Baawuah, 2015.…”

“…A review of these investigations shows that thermoplastic polymers and or their blends with metallurgical coke, graphite, or biomass are the dominant reductants often used for the production of metallic iron from reagent grade iron oxides or electric arc furnace (EAF) slags containing iron oxide (Dankwah et al, 2016). In addition to the above polymers and their blends, other researchers have utilised elastomers and thermosetting plastics as reductants (Dankwah et al, 2012, Mansuri et al, 2013, Rajarao et al, 2014a, Rajarao et al, 2014b, Nath et al, 2012, Dhunna et al, 2014and Dankwah and Baawuah, 2015. This category of polymers includes end-of-life rubber tyres, compact discs, melamine and bakelite as reductants or for carbon dissolution studies.…”

“…They achieved a maximum porosity at 850 °C with char surface area of 334 m 2 /g. Using the chars produced at 1550 °C as reductants they were able to achieve about 90% iron oxide reduction (Dankwah et al, 2016 oxide because the slag typically exists as a spinel fayalite, which is difficult to reduce carbothermally. Cheng et al (2013) investigated the direct reduction experiment on iron-bearing waste slag.…”

Recycling Waste Electrical Socket as a Carbon Resource in Ironmaking

“…However, most of the existing research in this area involves the use of thermoplastic polymers and or their blends with metallurgical coke, graphite, or biomass as reductants for the production of metallic iron from reagent grade iron oxides or electric arc furnace (EAF) slags containing iron oxide. For thermosetting plastics, Dankwah et al, 2012, Mansuri et al, 2013, Rajarao et al, 2014a, Rajarao et al, 2014b, Nath et al, 2012and Dankwah and Baawuah, 2015 have used endof-life rubber tyres, waste compact discs, end-oflife melamine and waste bakelite as reductants or for carbon dissolution studies. Rajarao et al, (2014b) for instance studied the structural changes in the chars produced during the rapid pyrolysis of waste compact discs (CDs) in the temperature range 550-1550 °C.…”