How to enable the steelmaking decarbonisation

The steel industry’s migration towards fossil-free operations is already underway. The most likely contender to the traditional operations is to use a production set-up of Hydrogen-based direct reduction process (H-DR) in combination with an electric arc furnace (EAF), using scrap and low-carbon (or carbon-free) direct reduced iron (DRI/HBI) as feedstock.
The transformation from traditional blast furnace (BF) – converter (BOF) operations to the future fossil-free configuration is a challenge that requires an in-depth analysis. The transformation will span over several years and will likely be performed in several steps to enable production targets while minimising risks.

Eliminate uncertainties and minimise risks with steelmaking decarbonisation

There are three main transitional uncertainties identified:

• How to secure iron-bearing feedstock over time.
• How to maintain the iron balance throughout the different steps of transformation.
• How to handle a decreased carbon content in steel processing.

Will there be a shortage in iron-bearing feedstock supply?

EAF steelmaking represents approximately 26% of the total global capacity (in the European Union, the corresponding figure is 42%). The EAF production share is expected to grow over time – a forecast that is likely to accelerate due to the industry’s current transformation.

Recently announced CO2-mitigation strategies from several ore-based producers, that use the traditional BF-BOF route, outline plans to convert to electric steelmaking based on the EAF and green iron feedstock. In some cases, there will be DRI/HBI available which is produced in-house to secure iron supply, but sourcing scrap from external sources will still be crucial in most cases.

Furthermore, in some parts of the world dedicated iron feedstock production units are planned to come online. These will primarily produce pig iron pigs or DRI/HBI, which may outpace the forecasted increased demand for scrap.

Even though it’s too early to fully understand the implications the upcoming changes will have on the scrap market, we can already see that there may be a regional shortage of iron-bearing feedstock, which will cause scrap prices to rise.

For the steelmaker it is imperative to maintain a sound iron balance during the transformation, which may pose a challenge with a shortage of feedstock. Virgin (pig) iron could be used to bridge the gap, which would remedy the scrap shortage and add carbon to the system. This considerably simplifies commissioning and tune-in of new processes, thus simplifying the transition towards fossil-free steelmaking while minimising commercial and financial risks.

Balance the plant iron flows during the transition towards steelmaking decarbonisation

Converting to fossil-free steelmaking operations in a single step is a tremendous challenge, and therefore a staged transition with parallel production for an extended period is preferred. This is something that was discussed in depth in our previous guide Challenges in integrated steelmaking decarbonisation.

A viable transition set-up includes the production of solid iron to accommodate for surplus production capacity in a BF (on- or off-site). The excess solid iron will then function as an EAF iron feedstock which improves flexibility and makes it easier to balance the iron flows at the plant.

Carbon-free feedstock – a steelmaking challenge

The total amount of carbon included in the feedstock is expected to decrease significantly in future fossil-free production systems and even, in some cases, approach zero. This is a dramatic change in steelmaking processing as carbon plays a significant role in controlling the oxygen potential, improving melting properties, reducing nitrogen pick-up, and generating CO-gas for slag foaming. All of these are important factors to control the EAF process’ thermal efficiency and product quality.

One compromise to ease the negative effects would be to add a controlled amount of carbon-containing material into the feedstock during an extended transition and ramp-up period. Preferably, carbon should then be dissolved in solid iron sourced from in-house excess production.

The next step towards steelmaking decarbonisation

In conclusion, the transformation towards fossil-free iron and steelmaking is already underway. It requires extensive investigations, planning, and strategic considerations before it can be executed. If you want to know more about how to master transformation towards a fossil-free future while maintaining productivity and product quality, read our guide GRANSHOT® enables the steelmaking decarbonisation.