8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

The recycling of steel plant by-products is a key issue for all steelmakers. For these materials to be fully utilised without incurring environmental and economical penalties they need to be better understood with respect to their composition (morphology, phases and phase distribution). Research is being undertaken that aims to realise the value of steel plant by-products to the Australian steel industry and minimise the amount of by-product going to long-term stockpile. Basic oxygen steelmaking (BOS) dust, is a major steel plant by-product stream that has been characterised. This characterisation will inform the assessment of reactivity of the material so that its potential use on plant or elsewhere can be evaluated. While BOS dust contains useful components such as iron units and fluxes, other components, such as zinc, can limit the amount of possible recycling within the steel manufacturing process, causing both process and/or occupational health and safety issues. BOS dust has been found to undergo a self-sintering process, improving its mechanical properties to allow easier recycling and utilisation on plant. It contains components including iron, flux and zinc units which have value on plant and elsewhere. Better understanding of the self-sintering process will allow better utilisation of this resource and help to minimise emissions and reduce costs by replacement of raw materials. In this paper, BOS dust characterisation by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and differential calorimetry (DSC) is presented and discussed.