Recycling industrial waste saves landfill space, conserves resources and minimises its environmental impact. Recently, a great deal of attention has been paid to the microwave heating process as an alternative recycling method. The present study aims to investigate the use of microwave energy as a heat source for the treatment of blast furnace sludge (BFS). BFS is treated directly with microwaves, without the addition of a reducing agent. BFS contains carbon (its Fe/C ratio is approximately one), which functions as a self-reducing agent. The original BFS sample and the products of its carbothermic reduction by microwave heating are characterised using X-ray diffraction, scanning electron microscopy, thermogravimetry and differential scanning calorimeter, Fourier transform infrared and X-ray photoelectron spectroscopy. It is found that, after microwave treatment, the haematite is completely reduced to metallic iron with some wustite. The findings of this study indicate that microwave heating can be used to process and recycle BFS generated by iron-making processes.
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