Jun 10 2022
New lower-emissions steel products are growing in the market, with Kobe Steel and Thyssenkrupp marketing grades which take into account the positive impact on carbon emissions from hot-briquetted iron and ferrous scrap used alongside iron ore to produce steel.
Kobe Steel's new zero-emissions steel made its way into suspension used in a Toyota Motor Corp. Corolla hydrogen-fuelled race car last week at the Fuji International Speedway, while Salzgitter and other companies are offering lower-emissions and carbon-accounted steels to buyers focusing on their procurement-related upstream Scope 3 emissions.
Steel producers operating blast furnaces are looking to optimize and introduce new ways to work with raw materials, such as HBI, hydrogen and biomass, and add renewable energy and fuel processes to downstream steel plants. Such changes may boost lower emissions steel volumes ahead of potential expansion in new technologies and applications later this decade in hydrogen-based direct reduction iron and molten oxide electrolysis which promise to slash steelmaking carbon emissions closer to zero.
Kobe Steel and Germany's Thyssenkrupp, which launched the HBI-based bluemint pure and scrap-based bluemint recycled flat steel product range, have taken on the approach of capturing the benefits of using HBI and scrap in their existing blast furnace process and applying the CO2 savings to a proportion of steel products.
Rather than using average carbon intensity in actual steel production methods, emissions savings are isolated to a portion of output with certified lower emissions being applied, using the so-called mass balance methodology. By selling steel with verified emissions, the companies can apply a carbon saving to the relevant product, appropriate with the raw material and calculated volume, and buyers are invited to use the emissions savings against their Scope 3 benchmarking.
Kobe Steel last month launched Kobenable Premier, a steel product with 100% reduction in CO2 emissions during manufacturing, and Kobenable Half, with a 50% reduction in emissions, compared with similar steel using a 2018-2019 fiscal year baseline. The Kobenable range with certified emissions reductions is available for steel sheet, steel plate, wire rod and bar products manufactured at the Kakogawa Works in Hyogo Prefecture, Japan, and the Kobe Wire Rod & Bar Plant.
The mass balance methodology, allocates CO2 reductions to specific steel products, in accordance with ISO 20915, Kobe Steel said.
"This approach has been used for products such as recycled plastics, bioplastics, electricity generated from renewable energy sources, and certified food products like cocoa and palm oil, for which separation of product properties are difficult due to the characteristics of the manufacturing process or the supply chain," Kobe Steel said in a statement. "In the ironmaking process, it becomes possible to reduce the amount of coke used and thereby reduce CO2 emissions by replacing a portion of iron ore with HBI, a raw material for steel that has already been reduced."
Thyssenkrupp highlighted the benefits of using emissions savings directly from using the materials in the blast furnace process into steel products, over applying carbon offsets to steel through other emissions reductions projects and third-party certificates.
Thyssenkrupp compared the emissions savings with its conventional reference steel product emissions of 2.1 mt emissions per ton of strip steel on a life cycle analysis basis taking into account Scopes 1-3. By using modelling, it simulated scrap charged at 100% into the blast furnace in the case of bluemint recycled, which is marketed with 0.75 mt carbon emissions. Scrap is already used in the basic oxygen furnace combined with pig iron for its conventional steel, and is not included in comparative savings applied, it said. Bluemint pure using HBI is marketed with 0.6 mt of carbon emissions, it said.
Cleveland Cliffs, Voestalpine and other companies are utilizing HBI in blast furnaces, also lowering the carbon intensity of steel produced at existing plants by cutting the need for coal and other reductant fuels.
Voestalpine and Kobe Steel have published studies using HBI with iron ore in reducing overall solid fuels to produce hot metal, with a cut mainly seen in PCI coal use rather than met coke. Coke's characteristics help support the burden during smelting, which has limited PCI's rates of substitution. Trials may see blast furnaces use greater proportions of HBI and scrap replacing iron ore products in blast furnaces, although blast furnaces traditionally fed mainly using iron ore products such as sinter, pellets and lump.
Cliffs said in 2021 its Scope 1 and Scope 2 greenhouse gas emissions on a per unit basis fell, aided by the use of HBI supplied internally from its Toledo DRI plant. Overall greenhouse gas emissions in 2021 rose to 34.5 million mt CO2 equivalent from 32.2 million mt in 2020, due to increased production volumes following the COVID effect in 2020, it said.
"Our increased consumption of scrap and our successful use of HBI in our furnaces to reduce coke rate, enhance productivity and quality, and stretch hot metal production led to an overall reduction in carbon intensity per ton in 2021," the steel, mining and scrap processing group said in its latest sustainability report.
In Europe, ArcelorMittal and Arvedi have long been producing flat steel via the EAF route, using mainly scrap in a process which leads to a lower carbon intensity compared with the blast furnace route. US and Japanese EAFs also produce flat steel products using scrap.
ArcelorMittal and Salzgitter earlier announced the production of flat steel using EAFs with certified use of renewable power, demonstrating low-emissions steel products for users trialing new grades and benchmarking for emissions.
ArcelorMittal has a range of long and flat steel products under the XCarb brand of recycled and renewably produced steel made via EAFs using scrap. ArcelorMittal also sells steel bundled with certificates from emissions reductions projects at its sites.
ArcelorMittal's EAF in Sestao, Spain, used 100% renewable power and a high proportion of scrap to produce HRC with less than 0.5 mt of CO2 on a cradle to gate life cycle basis, the company said after the first sale of the grade to re-roller Grupo Arania in March.
Salzgitter has offered cold-rolled and galvanized coil with emissions reductions of as much as 66% by producing the grades using its Peine EAF combined with rolling at the Salzgitter Flachstahl works. Bypassing its regular blast furnaces, the company is offering small volumes of low-emissions certified flat steel to Mercedes-Benz, Bosch, Siemens, Gaggenau, Miele, and Neff. SSAB supplied Volvo Group pilot EAF-based steel in trials, produced with partners as the Swedish company invests in its first EAF in Europe to start up in 2026.
Thyssenkrupp and Salzgitter have plans to invest in DRI plants and seek to contribute to lowering emissions significantly with major operational changes. While Thyssenkrupp intends to decommission its blast furnaces over time, the company sees integrating HBI-based steel production into the current integrated site at Duisburg-Hamborn as already cutting emissions towards its goal, while gaining experience in handling HBI for steel production.