Interfacial Reactions between Coke/HDPE Blends and High Carbon Ferromanganese Slag

Abstract

The reduction of MnO in slag by blends of coke with high density polyethylene (HDPE) was investigated by the sessile drop method at 1 500°C in this study. The results show improved wettability and extents of reduction are realised with the use of an HDPE/coke blend in this system by comparison to reduction by pure coke, whereby increasing HDPE content resulted in further improvement in extent of reduction and increased wettability. The extensive devolatilisation from HDPE samples is the primary cause for these improvements, whereby the gasified HDPE created both CH4 and H2 reducing gases. Additionally, increased sample porosity allowed for improved wetting, and thus improved reduction capabilities. The dynamic contact angle between the carbon substrate and the slag varied, with HDPE samples ranging between 140°-60°, whilst the coke samples ranged between 160°-120°. The addition of HDPE allowed for the near complete reduction of MnO and partial reduction of SiO2 from the slag with distinct metallic regions of Mn-Si formed in the sample; regions containing pure Si were also found.

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

“…The amount of gas evolved during the Fe–C interaction was monitored to investigate the effect of gas generation on the deposition of ash layer at the metal surface and thus the dissolution of carbon. The gases species released from HDPE/coke blends were expected to consist of CO, CO 2 , and volatile matter (mainly H 2 and CH 4 ) . An Infrared (IR) gas analyzer was used to continuously measure the accumulation moles of CO and CO 2 generated during the Fe–C interactions at 1823 K for coke and the blends, and the results are showed in Figure .…”

“…Recent developments through laboratory‐based research have shown that waste HDPE can be used as a partial replacement for coke in steelmaking process . These researches focused on using waste HDPE as a carbon source for studying the behavior of slag foaming, the reduction of iron oxide, and manganese oxide in the molten slag, the wettability and interfacial phenomena between carbon and liquid iron at 1823 K . However, behavior of carbon dissolution from waste HDPE into liquid steel and its kinetics rate has not been clearly determined.…”

Plastics—Villain or Hero? Polymers and Recycled Polymers in Mineral and Metallurgical Processing—A Review

“…The reduction of MnO in slag by blends of coke and high-density polyethylene (HDPE) shows improved wettability and reduction efficiency compared to reduction by pure coke. Increasing HDPE content resulted in further improvement in reduction and wettability and allowed for the near complete reduction of MnO and partial reduction of SiO 2 to Si from the slag [ 85 ]. Decrease in CO 2 emission as well as the evolution of CO and CH 4 indicated the thermal decomposition of the polymer to liberate significant amounts of CH 4 [ 85 ].…”

Reaction Behavior of Coke in a High Alumina Slag

“…Due to the consume of carbon, the molten slag could in contact with the ash minerals directly, and the oxides of coke ash had a good wettability with slag, which may promote the penetration of slag into coke by wetting the ash oxides. 21) The increased coke porosity could also improve the wettability of the coke with slag as well as increase the reaction capabilities of slag oxides with coke, 22) therefore leading to the degradation of the coke. Furthermore, the slag could dissolve the coke ash minerals and react with that to form new phase in the penetration or flow process, which may change the coke integrity as well as the mineral catalytic ability and then influence the reactivity and strength of the coke.…”