The metals industry is standing at a crossroads: Its products are indispensable for all modern societies – today and in the future. But its current production processes are no longer future-viable because their CO2 footprint is too big.
Almost ten percent of global greenhouse gas emissions stem from the production and processing of steel, aluminum, copper and other non-ferrous metals. The good news: The roadmap towards climate neutrality in the metals sector is taking clear shape.
The roadmap to climate-friendly production
The technological potential for a carbon-neutral and sustainable metals industry is enormous. We are committed to preparing the ground for this transition for our customers and to actively advancing the transformation in the metals industry. This applies not only to production, but also to recycling, as the re-use of metals plays a key role in the vision of a sustainable circular economy.
The blast furnace in focus
In order to promote the decarbonization of the steel industry, it is essential to focus on the primary stage of iron making, as this stage accounts for more than 80 percent of the greenhouse gas emissions. In new facilities, the key to reducing greenhouse gas emissions to zero is the combination of green hydrogen, direct reduction and the electrification of all downstream processes. In existing integrated steelworks, we substitute carbon-containing fuels to an increasing extent by converting and modifying existing plant facilities and infrastructures step by step. This approach relies on the in-depth analysis of all energy balances and flows of material throughout the works.
In order to support our customers on their path towards decarbonization even more efficiently, we recently acquired all shares of Luxembourg-based Paul Wurth, which has been part of SMS group since 2012. In April 2021, we acquired the remaining shares from the Luxembourg state and state-owned banking organizations. Jointly, we will focus on metallurgical challenges and on advancing hydrogen technologies. In addition, we boast expertise in direct reduction plants, environmental protection solutions and recycling technologies, and will place special emphasis on the development and implementation of technologies promoting CO2-neutral steel production. Paul Wurth – like SMS group – looks back on 150 years of experience.
Our future offering will include, in addition to a CO2-free direct reduction process for iron ore, a series of other technologies for the reduction of CO2 emissions in existing steel mills. We will also offer Power-To-X technologies for the production of synthetic fuels and downstream products.
We will pool our group-wide research and development activities for decarbonization and recycling at the Luxembourg site. Additionally, a strategic partnership has been agreed with the University of Luxembourg, where – with financial support from Paul Wurth – a chair for energy process technology has already been established.
We offer the full range of decarbonization technologies
1 – Blast furnace – BOF converter
The integrated blast furnace-BOF route uses large amounts of iron ore – in many cases, ore with only low iron content. In this route, limited quantities of scrap (about 20 percent) can be added during the BOF process. Due to the massive use of coke for iron ore reduction, the BF-BOF route is the steelmaking route with the highest CO2 emissions.
Technology from Paul Wurth provides a substantial enhancement of the blast furnace and the cokemaking processes, reducing the coke rate and the CO2 emissions as a result. In order to maximize the scrap rate, electric arc furnaces or, for example, the SMS CONPRO technology can be used in the steelworks. This approach is only limited by the fact that quality requirements may rule out the use of scrap due to the potential risk of contaminations in the scrap.
2 – Direct reduction – melting unit – BOF converter
The blast furnace is substituted by a combination of the MIDREX® direct reduction process and a melting unit. It is possible to initially run the direct reduction process on a natural-gas basis, then use hydrogen in place of natural gas at gradually higher rates. Also in this process configuration, electric arc furnaces can be used in the steelworks to increase the scrap rate.
The main feedstock in this process route continues to be iron ore pellets – also in this case, of rather low iron content.
Before it can be refined in the BOF converter, the molten pig iron has to be carburized. To this purpose, CO-containing waste gas from the converter process can be recirculated into the MIDREX® direct reduction process (carbon cycle).
Like the slag from the blast furnace, the slag arising in the melting unit is a valuable, emission-reducing raw material for the construction material industry (cement).
3 – Direct reduction – electric arc furnace
In a greenfield approach and with green hydrogen available at competitive prices in sufficient quantities, a completely different route can be adopted.
The reduced higher-grade iron ore can be melted directly in an electric arc furnace and refined into steel. No intermediate step is required and – depending on the specified final grade – only minor carburization is needed. From the very beginning, scrap can be added to the furnace at higher rates, with only the quality requirements of downstream processing stages setting an upper limit here. This set-up provides the highest decarbonization potential.
We have been concentrating on developing solutions that optimize production and reduce emissions at the same time. Due to the increasingly stringent environmental and climate protection regulations, we have been experiencing high demand for products in our current portfolio.Thomas Hansmann,
Executive Vice President Metallurgy, SMS group
Hydrogen as a green product
In order to be able to use hydrogen profitably in the steel industry, it must be available in sufficient quantity. Currently, there are still not sufficient production capacities.
Since 2019, we have been a strategic investor in and technology partner of Sunfire. The German company has developed an efficient high-temperature electrolysis process. The difference between high-temperature and conventional electrolysis is that steam is used instead of liquid water. Steam provides the advantage that it can be more easily separated into hydrogen and oxygen. Since the steam can be generated using waste heat from industrial facilities, this process is suitable for every steelworks. Not only can 20 to 30 percent of energy be saved compared to conventional electrolysis, this process is also significantly more efficient.
The hydrogen produced on site can be directly used in the blast furnace and the steelworks – or for other purposes. The Sunfire technology will, for example, be used in a lighthouse project in Norway: At Norsk e-Fuel, CO2 is going to be converted into renewable fuels using wind- and hydropower. The MULTIPLHY project in Rotterdam involves the construction and operation of a multi-megawatt high-temperature electrolyzer. The 960 tons of green hydrogen expected to be produced by the end of 2024 will avoid approximately 8,000 tons of greenhouse gases.