Reduction of FeO in EAF Steelmaking Slag by Metallurgical Coke and Waste Plastics Blends

In Australia, the increasing use of plastics has resulted in less than 20% being recycled, posing significant environmental challenges. This study aims to address this issue by exploring the reduction of EAF slags containing 47% FeO using blends of metallurgical coke and High-Density Polyethylene (HDPE) plastics at a temperature of 1500 °C. A laboratory-scale horizontal tube furnace was employed for experiments, alongside off-gas analysis conducted with an infrared gas analyser and multiple gas chromatographic analysers. The findings demonstrate that the FeO reduction rate in slags significantly increased with the use of coke/plastics blends, with the optimum results indicating a reduction rate that was over twice that of pure coke. Additionally, the CO2 emissions in the off-gas were reduced by approximately 75% as the polymer content in the blend increased, further improving the degree of carburisation and sulphur removal from the metal. These enhancements in reduction efficiency, carburisation, and desulphurisation are primarily attributed to the reactions involving hydrogen released from the waste plastics at high temperatures.