No abstract

One of the largest problems facing the steelmaking industry is the high amount of waste currently produced and the low amount of waste that is currently recycled. This study aims to look at the suitability of 3 different samples of basic oxygen steelmaking (BOS) slag as a construction material, in concert with their carbon capture capacity. Characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma spectroscopy (ICP), X-ray fluorescence (XRF), CO2 adsorption analysis, and thermogravimetric analysis (TGA) demonstrated that these BOS slags were found to have several favorable characteristics making them suitable for reuse as construction material.

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.