SSAB’s modernised steel mill in Oxelösund will begin operating in 2025, reducing carbon dioxide emissions by up to 90% in one hit. So how will that happen? And how will SMA Mineral help with the transition? We asked Göran Grimfjärd, an experienced steelmaking consultant, to explain by using his own knowledge and delving into the material available on the SSAB and Hybrit websites.

How can CO₂emissions be reduced in today’s integrated mills?

In the process from ore to blast furnace pellets, LKAB has already reduced its energy consumption and CO₂ emissions by 85%, from 190 kg to 30 kg CO₂ per tonne pellets (ref. 1).

Co₂ emissions from blast furnaces can be further reduced by replacing fossil coal with renewable bio-coal, wood waste or hydrocarbons from e.g. plastics waste. Bio-oil can replace fossil oil in the same way. Trials in the blast furnace in Raahe showed that injecting bio-coal as a fossil coal replacement can reduce CO₂ emissions by 200,000 tonnes per year.

CCS (Carbon Capture and Storage) is another technology, where CO₂ is captured at the blast furnace and piped to bedrock storage. Reportedly, CCS is able to reduce blast furnace CO₂ emissions by around 30%, but it is costly.

In LKAB’s research blast furnace in Luleå, CCS technology has been combined with returning gas from the furnace to the process. This has allowed a further CO₂ emissions reduction to a total of 50% (ref. 1).

What do we need to do to achieve the 1.5 degrees goal?

Assuming an increase in global steel production from 1,600 million tonnes per year in 2015 to 2,500 million tonnes in 2050, the above-mentioned emissions of 1.8 tonnes CO₂ per tonne steel will have to be reduced to 200 kg per tonne, i.e. by almost 90% (ref. 1), to meet the 1.5 degree goal established by the Paris Agreement. However, we can see that possible measures concerning the biggest source of emissions – the blast furnace – will not be enough.

SSAB then carried out two studies to see if it is technically and financially feasible to switch from coal-based to hydrogen-based metallurgy to produce fossil-free steel that reduces CO₂ emissions by 90%. The feasibility studies gave positive results! SSAB, LKAB and Vattenfall formed a collaboration known as the HYBRIT initiative.

They decided to start a pilot direct reduction project, where the iron oxides in ore are reduced to sponge iron (DRI) by hydrogen (or fossil-free alternatives) produced using fossil-free electricity from Vattenfall. DRI can be turned into hot briquetted iron (HBI). Pilot studies are also in progress in which DRI/HBI and scrap (in various mixtures) are smelted into steel in an electric arc furnace (EAF).

The companies would achieve net zero CO₂ emissions by replacing fossil energy carriers with biofuels or other fossil-free energy carriers. Together with energy conservation and increased electrification, the three companies will make a significant contribution to limiting global warming. LKAB will also increase the level of processing in its products
through delivery of sponge iron (DRI/HBI).

The pilot studies had good outcomes. Thus HYBRIT has given the start signal for the next step on an operational scale, a direct reduction plant at LKAB and an electric arc furnace steel mill at SSAB Oxelösund.

Ref. 1) Toward a Fossil Free Future with HYBRIT:
Development of Iron and Steelmaking Technology
in Sweden and Finland. Metals 2020 (10) 972.

The new process chain (right section):
• fossil-free fuel with zero CO₂ emissions
• used for pelletisation

• coke works will be phased out
• blast furnace installation will be phased out
• oxygen steel mills will be phased out
  • large-scale hydrogen production via electrolysis; storage
  • reduction using hydrogen emits only water vapour – no greenhouse gases!
  • reduction using hydrogen requires additional energy supply (previously by burning coke in the blast furnace)
  • electric arc furnace must be able to smelt mixtures of DRI/HBI and scrap, from 100% scrap to 100% DRI/HBI
  • The LKAB DRI/HBI plant will go into operation at the same time as the electric arc steel mill in
  Oxelösund (which belongs to SSAB).

Energy consumption, CO₂ emissions and cost per tonne steel
• If we convert the energy metrics on either side to kWh, we see that the left-hand process chain including the coke works and pelletising consume a total of 5,825 kWh per tonne of steel.

• The right-hand HYBRIT side consumes 4,090 kWh per tonne of steel.
• Thus HYBRIT only consumes 70% of the coal-based process chain’s requirements, despite the energy intensive electrolytic hydrogen. HYBRIT is estimated to be about 20% more expensive per tonne steel (based on current prices for raw materials, energy and emission allowances).

Fossil-free steel has become a veritable race

• Almost all steel companies are showing great interest.
  • There is a ‘lot of chatter’ and a lot of state aid.
• SSAB and HYBRIT have lofty ambitions, are investing resources and seem to be maintaining their lead,
  but they can hear the competition panting right behind them.

The steel industry accounts for 7% of all global CO₂ emissions. More so in Sweden – 10%. Most of the world’s production takes place in integrated mills with a process chain all the way from ore via blast furnaces (BF) and oxygen steel mills (BOF), to finished steel. This type of plant has the greatest CO₂ emissions – around 1.8 tonnes of CO₂ per tonne of steel. SSAB’s three Nordic mills are of this type.

But 30% of the steel is also produced in scrap-based mills, with the process chain: Scrap => electric arc furnace (EAF). The coal-intensive step is missing here. Thus CO₂ emissions are only
10% of those in an integrated mill.

The blast furnace process has existed for a long time; it has enjoyed magnificent development and was virtually unchallenged as a reduction process. But it is under increasing scrutiny because of its carbon footprint.

Coke, produced from fossil coal in a coking plant, plays two parts in a blast furnace – the supply of energy through combustion and the reduction of ore. Great amounts of carbon dioxide are formed during combustion and reduction in the blast furnace, and when the carbonaceous hot metal from the blast furnace is refined into steel in the oxygen steel mill.

Facts about the companies

SMA Mineral produces and supplies important lime raw materials to the paper, chemical and steel industries. This includes the blast furnaces and steel mills at SSAB’s units in Oxelösund, Luleå and Raahe (Finland). SMA Mineral has its own installations for the extraction and processing of raw materials, with the latter also at SSAB’s production sites.

SSAB is a successful supplier of special steels and advanced expertise in their applications for the automotive, transport and civil engineering industries. SSAB produces steel in Oxelösund, Luleå, Raahe (Finland) and the USA.

Photo: SSAB