Circored Fine Ore Direct Reduction as one Route towards Carbon-free Steel
1.4 Direct reduction and smelting reductionSebastian Richter1, Max Koepf1
1 Metso Outotec
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Europe’s Green Deal, announced in March 2020, with its legally binding target to climate neutrality by 2050 tremendously accelerated the dynamics for the development of carbon-free steelmaking technologies. About 70% of the world’s steel is produced via the BF route, an efficient but highly carbon-intensive process. With limited investment cycles left until 2050, the steelmaking industry is faced with the decision which alternative technologies for iron or reduction to invest in within the next 5-10 years.
One widely discussed solution is the hydrogen based direct reduction and EAF route to replace blast furnace-BOF steelmaking and most projects focus on shaft furnaces for the direct reduction with hydrogen. However, a conversion to this process only would create a gap of several hundred million tons of DR-grade pellets with all the impacts on pellet availability and prices.
One alternative is the hydrogen based direct reduction, using fine ore instead of pellets. Metso Outotec’s Circored process has proven functionality in an industrial scale pilot plant. The process is based on the unparalleled fluidized bed experience developed by Metso Outotec and applied in hundreds of different plant, e.g. for calcining, roasting, or coal combustion. For the direct reduction of fine iron ore, Circored applies a two-staged reactor configuration with a CFB (circulating fluidized bed) and a downstream FB (fluidized bed). The first-of-its-kind plant with a capacity of 500 000 t HBI/a commenced operations in 1999 in Trinidad. In several months of successful operation 300,000 tons of high-quality carbon-free HBI were produced and it became evident that the basic process concept was ideally suited for this application.
This paper describes the principle of the Circored process and the operational results of the pilot plant. Additionally, the possible role of Circored fine ore reduction in the conversion of the steel industry towards green steel is discussed.
