Utilisation of post-consumer plastics in pre-reduction of higher manganese oxides in ferromanganese process

Abstract

The pre-reduction of higher manganese oxides with post-consumer plastics as reductants has been investigated through experiments conducted in a laboratory scale horizontal tube furnace coupled with an off gas analysis through an online infrared (IR) gas analyser. Composite pellets of calcined manganese oxide (Mn 3 O 4 ) with high density polyethylene (HDPE) (at C/O molar ratios of 1?5, 2?0 and 3?0) were heated rapidly to 1150uC under pure argon and the off gas was measured continuously by an IR analyser for CO, CO 2 and CH 4 . The extent of reduction of Mn 3 O 4 to MnO was calculated from a mass balance for removable oxygen. Solid reaction products were characterised by scanning electron microscopy and X-ray diffraction analysis was used to confirm the presence of MnO. The results indicate that Mn 3 O 4 can be successfully pre-reduced to MnO using HDPE as a reductant. Gas analysis studies indicated that the polymer is first converted to CH 4 which cracked partially or reformed to H 2 , C and/or CO. Reduction of Mn 3 O 4 to MnO was subsequently effected by C, CO, H 2 and the residual CH 4 .

Calcination Behaviour of Nsuta Rhodochrosite Ore in the Presence and Absence of End-of-Life High Density Polyethylene

“…In all these investigations no polymers were added and, accordingly, there was no investigation on the effect of gases from the thermal decomposition of polymers. The addition of a polymer to metal reduction processes is thought to have an attenuating effect on especially the CO2 that is evolved into the atmosphere (Dankwah et al, 2011;Dankwah et al, 2012;Dankwah et al, 2013). Dankwah (2014) grade MnCO3.…”