Recent Trends in Ironmaking Blast Furnace Technology to Mitigate CO 2 Emissions: Top Charging Materials

The iron- and steelmaking is the largest energy consuming in the industrial sectors. The high energy consumption is associated with emission of CO2 and other pollutants. The most common ironmaking process used in the world is the blast furnace which contributes around 70 % of the world’s steel production. Recently, blast furnace has undergone tremendous modifications and improvements to reduce the energy consumption and CO2 emissions. The modifications are being focused on two main approaches: (1) development of top charging materials and (2) injections of auxiliary fuels through blast furnace tuyeres. The present chapter will discuss the recent modifications and development in the top charging burden and how it could participate in minimizing the energy consumption and CO2 emissions for more efficient and sustainable iron and steel industry. The injection of auxiliary fuels will be discussed in details in another chapter. The enhancement of burden material quality and its charging mode into the blast furnace has resulted in a smooth and efficient operation. Recently, the usage of nut coke in the modern blast furnace is accompanied by higher production and lower reducing agent rates. An efficient recycling of in-plant fines by its conversion into briquettes with proper mechanical strength is applied in some blast furnaces to exploit the iron- and carbon-rich residues. Nowadays, novel composite agglomerates consist of iron ores and alternative carbonaceous materials represent a new trend for low-carbon blast furnace with lower dependence on the conventional burden materials. The recent investigations demonstrated that the novel composites are able to reduce the thermal reserve zone temperature in the blast furnace and consequently enhance the carbon utilization through its higher reactivity compared to fossil fuels. The top charging of bio-reducers and hydrogen-rich materials into the blast furnace is one of interesting innovations to mitigate the CO2 emissions. Although some of previous approaches are recently applied in the modern blast furnace, others are still under intensive discussions to enhance its implementations.