© ICS 2018 - 7th International Congress on Science and Technology of Steelmaking: The Challenge of Industry 4.0. All rights reserved. In general, the recycling of steel plant by-products is a critical issue for the industry, requiring a thorough assessment of the material characteristics before pursuing an economic and environmentally sound sustainable treatment approach. Research is underway that aims to realise the value of steel plant byproducts to the Australian steel industry and minimise the amount of by-product materials going to long-term stockpiles. Dust from basic oxygen steelmaking (BOS), one of the largest steel plant by-product streams, was characterised in terms of its composition, physical properties and reactivity so that its potential use on plant or elsewhere could be assessed and evaluated. While BOS dust contains recoverable 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 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, characterisation of the BOS dust by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis, X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and differential calorimetry (DSC) is presented and discussed with a view of understanding the reaction behaviour of the materials in air and its effects on the formation of bonds (and consequently strength) within the BOS dust.