Biochar enables more environmentally friendly steelmaking

Oct 16, 2020

The application of fossil fuels, such as coal and coal-derived coke in iron ore processing and steelmaking, contributes to 20 % of total global industrial fossil fuel consumption (Abdelazis et al. 2011). Moreover, steelmaking industries account for 6.7 % of global CO2 emissions, mainly because of the excessive use of fossil fuels (Brown et al. 2012). In the last two decades, tremendous efforts are laid towards minimizing the negative environmental impact caused by the iron and steel industry.

As a renewable fuel source, biochar produced from waste biomass is gaining interest as an alternative to coal and coke in steelmaking. Thus far the results of researchers and industries have shown that biochar has the potential to find its place in coking, sintering, metalized pallets production and as a carbon source in Blast Furnace (BF) processes and Electric Arc Furnaces (EAF) processes (Ye et al. 2019). 

Even though the blast furnace process is used for 64 % of the total global iron and steel production, the application of EAF in steelmaking has significantly increased in the last decade (Ye et al. 2019). One of the reasons for that is the shorter processing route of EAF that shows 75 % lower CO2 emissions when compared with BF processes (Ye et al. 2 019).

Nevertheless, EAF just like BF uses coke and anthracite coal as a fuel source, slag foaming agent, and steel recarburizer.  Therefore, the potential of using biochar from renewable sources will further help to minimize the carbon footprint of EAF steelmaking. Furthermore, biochar shows better foaming properties, due to high volatile constituents (Fidalgo et al. 2015), resulting in a more stable and optimal process, minimizing electrode wear. However, further research and testing are necessary due to several unfavorable biochar features, such as high ash content and high reactivity index, resulting in unstable effervescence (Ye et al. 2019).

Real-time measurements to accelerate the biochar development

Luxmet’s optical technology has been proven in the on-line measurement of the EAF phenomenon. This has already led to significant improvements of EAF energy efficiency.  Furthermore, Luxmet’s technology can be used for the evaluation of the potential application of biochar in the EAF process and better understanding of its foaming characteristics.

Luxmet’s technologies, enabling real-time measurements inside of the EAF, can play a crucial role in accelerating the research of biochar in steel making. We see biochar as an excellent way to decrease the carbon footprint of the steel industry by utilizing waste. This could solidify EAF’s advantages over the blast furnaces as a more environmentally friendly process. We are sure that our technology will be part of a more environmentally conscious future, evolving our slogan from “More steel with less energy” to “More steel with less emissions”!

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