Life cycle carbon footprint of electric arc furnace steelmaking processes under different smelting modes in China

Electric arc furnace (EAF) steelmaking process is an important way to realize recycling of scrap resources and sustainable development of iron and steel industry, which is orderly guided and major promoted during the 14th Five-Year Plan for achieving the carbon neutrality goal before 2060. The smelting modes with full scrap and hot metal added are two main methods in EAF steelmaking process in China, and there is still a lack of effective quantitative means and consensus on the smelting mode of lower carbon emissions. In this paper, based on the function unit of 1000 kg of molten steel, the life cycle carbon footprint (CF) of EAF steelmaking process under 13 current smelting modes were comprehensively analyzed and quantized. The results showed that with the hot metal ratio increased by 80.29%, the life cycle CF increased by 962.718 (45.85%) kg CO2 eq, the upstream CF of blast furnace ironmaking and sintering increased by 1944.544 (63.50%) and 674.194 (22.02%) kg CO2 eq. Reducing the hot metal ratio or indirect CF of hot metal production will rapidly lower the total CF of EAF steelmaking process. With the mass of carbon powder and natural gas increased by 24.82 and 9.84 kg, the life cycle CF decreased by 52.81 and 82.03 kg CO2 eq, respectively. Adopting full scrap smelting mode with appropriate amount of carbon powder and natural gas, or applying clean energy power production and low-carbon materials will be the best choice of future EAF steelmaking process.