Utilization of Waste HDPE for Sustainable EAF Steelmaking: Carbon Dissolution into Liquid Steel

Abstract

Carbon dissolution from blends of metallurgical coke with high-density polyethylene (HDPE) into liquid steel at 1823 K is investigated in-depth. HDPE is blended with metallurgical coke into three different ratios (blends H1, H2, and H3) and used as a carburizer. Compared to coke, a significant improvement in carbon dissolution is observed in the case of blend H3 with the carbon picked up by liquid steel after 60 min of reaction and the dissolution rate (K) is 4.5 wt% and 15.2 Â 10 À3 s À1 , respectively. For coke alone, the melt carbon content is 0.8 wt% and the dissolution rate of 0.3 Â 10 À3 s À1 . SEM micrographs and corresponding off-gas analysis reveal that the gasification of HDPE/coke blends slow down the coverage of ash oxides at the Fe-C interface and modify morphology of the ash layer. The associated reactions of volatiles generated during the thermal degradation of the polymer can aid the carburization of liquid steel to some extent. However, the amount of gas generated must be high enough to overcome the effect of ash oxides at the Fe-C interface. This study has strong implications in enhancing the potential of recycling waste polymers for sustainable steelmaking.

Utilization of polymeric wastes in steel refining process: Carbon dissolution into liquid steel at high temperature

“…It was then inserted into the hot zone where the temperature was 1550 °C. The reaction time was noted to start when the iron chips had melted and from a spherical droplet (∼1 min) [ [12] , [13] , [14] ]. The crucible was quenched at 1, 2, 4, 8, 10, 15 and 30 min.…”

“…Several previous studies have shown that waste polymers can be utilize as a carbon resource in steelmaking processes by partially blending with metallurgical coke (up to 30 wt%) and used for various studies, such as carbon dissolution, slag foaming, FeO and MnO reductions in molten slag [ [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] ]. Most of these works had focused on the utilization of HDPE, PET, PP, PU, PC, Bakelite, melamine and rubber tire.…”

Review on the Use of Alternative Carbon Sources in EAF Steelmaking

“…In both cases, the polymer/coke blends showed higher volume ratios than the slag foaming with coke alone. Kongkarat et al [67] also tested the carburization of pure iron with coke and HDPE/coke blends in a horizontal tube furnace. The addition of HDPE to the coke increased the carbon dissolution into the liquid steel depending on the amount of HDPE in the blend.…”

Utilization of Rubber Tree Bark for Reduction of Mill Scale at 1550 °C: Implication for Sustainable Wastes Recycling in Steelmaking Process

“…The consumption of these fossil fuels worldwide in these industries is quite high, leading to greenhouse gas emissions and various environmental problems. Thus, several research studies have been conducted toward the reduction of fossil fuels consumption [1][2][3][4][5][6]. The uses of high-density polyethylene (HDPE) plastic and rubber tires by blending with metallurgical coke as FeO reductant and slag foaming agent at 1550 °C have been investigated [1,2].…”