Avenues of resources efficiency enhancement in iron and steel production

Abstract

Ironmaking- steelmaking is a material and energy intensive process with a resource efficiency of only - 33 %. Resource efficiency enhancement requires recovering the wasted/unutilized material by-products and the energy associated with them in various forms. This review attempts to identify the material leakages and energy losses at each step of steelmaking (from iron ore mining) and explores approaches to plug the energy and material leakage; material efficiency brings in energy savings indirectly. Besides the material loss, accumulation of the by products (slime/tailings, steel slag, etc.), carbon emission, etc., cause environmental and ecological damage. The review discusses the prospects of slimes/tailings beneficiation through physical and physicochemical methods (often after some pre-treatments). The manuscript also discusses the need to recover heat from molten slags (BF slag and BOF slag) to reduce the energy intensity. Further, it discusses the endeavours to overcome the latent hydraulic activity of granulated BF slag and ways to enhance the acceptability of BOF slag in different applications. A brief sum-up of global efforts towards net zero emission (in line with the Paris Declaration) through carbon recycling, low emission intensity processes, alternate fuels, etc., is included. Lastly, the authors list the challenges of the Indian iron & steel industry and the efforts from the government and steel industries towards achieving the projected crude steel production (300 million tons) without crossing the emission intensity thresholds (Paris Declaration). The endeavours strengthen the sustainability of the steel industry.