Abstract
The global pandemic response to COVID-19 has led to the generation of huge volumes of unrecyclable plastic waste from single use disposable face coverings. Rotary hearth furnaces can be used to recover Zn and Fe from non-recyclable steelmaking by-product dusts, and waste plastic material such as facemasks could be utilized as a supplementary reductant for the rotary hearth furnace (RHF), but their fibrous form makes milling and processing to appropriate sizing for RHF application extremely challenging. A scalable method of grinding facemasks to powder by melting and mixing with Welsh coal dust reported herein provides a solution to both environmental challenges. The melt-blended PPE/coal dust shows a dramatically improved CO2 gasification reactivity (Ea = 133–159 kJmol−1) when compared to the untreated coal (Ea = 183–246 kJmol−1), because of improved pore development in the coal during the pyrolysis stage of heating and the catalytic activity of the CaO based ash present in the facemask plastic. The results are promising for the application of waste facemasks in recycling steelmaking by-product dusts in rotary hearth furnaces and may also be suitable for direct injection to the blast furnace subject to further study.
Highlights
The global pandemic response to COVID-19 has led to the generation of huge volumes of unrecyclable plastic waste from single use disposable face coverings
If the gasification reactivity of low volatile content coal can be substantially improved by pre-treatment with waste facemask plastic, it may be applicable as a means of economically increasing the productivity of rotary hearth furnace (RHF) plants through reduced pellet hold times
The observation that charcoal is not seen to increase in reactivity with the addition of facemask plastic, but the ground coal injection (GCI) coal sample does, has two potential explanations
Summary
The global pandemic response to COVID-19 has led to the generation of huge volumes of unrecyclable plastic waste from single use disposable face coverings. Rotary hearth furnaces can be used to recover Zn and Fe from non-recyclable steelmaking by-product dusts, and waste plastic material such as facemasks could be utilized as a supplementary reductant for the rotary hearth furnace (RHF), but their fibrous form makes milling and processing to appropriate sizing for RHF application extremely challenging. The results are promising for the application of waste facemasks in recycling steelmaking by-product dusts in rotary hearth furnaces and may be suitable for direct injection to the blast furnace subject to further study. If the gasification reactivity of low volatile content coal can be substantially improved by pre-treatment with waste facemask plastic, it may be applicable as a means of economically increasing the productivity of RHF plants through reduced pellet hold times
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