An image of a worker at a steelmaking facility

By Geoffrey Brooks, Joint Swinburne/CSIRO Chair in Sustainable Mineral Processing

The drive to decarbonise the world’s steel industry is gaining momentum, but how quickly can new low carbon steelmaking technology be implemented?

Revolutions are exciting and invigorating but they can also be unpredictable. Technological revolutions have become the norm in much of the world in recent decades, particularly in IT and communications.

Other technological changes move slower. An example of this is energy generation, where the capital-intensive industry is linked to stable social structures that can take decades to adapt to changing circumstances and new technology.

Moving from playing music on a CD player to online streaming services is by nature a much quicker transition than closing coal mines and power stations.

Trending towards green across the globe

The giant international steel industry is in a state of flux and, like any large international industry, change is a given. However, in recent times, the drive to decarbonise steel production is leading many to think that we are on the verge of a revolution.

Steel production contributes eight to ten per cent of the world’s human-made carbon dioxide, with most of the carbon dioxide generated from the ironmaking step of the process.

An image of a blast furnace

Image credit: Kichigin/

This step is where iron ore is essentially converted into an impure iron using either coal or natural gas to fuel the furnaces and remove oxygen from the ore in ironmaking, before refining the material to steel in steelmaking. There is growing pressure in the developed world for heavy industries like steel to decarbonise.

The pressure on industry is most apparent in the EU, where there has been significant investment, often government and industry in partnership, in developing new low carbon routes to steel at an industrial scale.

In Sweden, an industry consortium is developing hydrogen-based ironmaking technology (in which hydrogen replaces hydrocarbons) and electric arc furnace (EAF) steelmaking powered by renewable energy on greenfield sites, with plans to build large-scale facilities capable of producing millions of tonnes per annum before the end of this decade.

In the UK, the process of closing existing blast furnace facilities – which involve coal-based ironmaking technology – and replacing steelmaking facilities with scrap fed EAFs connected to renewable energy is well underway. Job losses in the thousands have been reported with this rapid change.

In Germany, thyssenkrupp – who operates blast furnaces – has been trialling replacing some of the carbon currently being used with hydrogen to find a way to gradually phase out the use of coal from its plants. Early analysis from thyssenkrupp suggests that the replacement of carbon with hydrogen can only lower the carbon dioxide generated from the existing technology by 20 per cent, which is much lower than the 90 per cent required to satisfy net zero scenarios by 2050. Many believe that the blast furnace will need to be phased out to achieve the 90 per cent reduction, with either the carbon in ironmaking to be replaced by hydrogen and/or the current furnace-based technology to be replaced by an electrolysis route.

Another example comes from Dutch steelmakers Tata Steel in the Netherlands, which has recently relined its blast furnaces, suggesting that it is expecting the technology to operate well beyond 2030. Simultaneously, the steelmaker has plans to install new hydrogen ironmaking facilities and an EAF for steelmaking on the same site as its blast furnace – essentially pursuing a hybrid strategy to decarbonisation.

From revolution to evolution

There is growing evidence that there is some shift from the expected revolution towards a more gradual evolution. Experts from Primetals, a major equipment provider to the industry, recently predicted that the blast furnace route will still dominate iron production well after 2040 and will still be producing around a third of the world’s steel by 2050.(1)

The pushback on rapid decarbonisation is strongly linked to concerns about the cost and scale of green hydrogen production.

Currently, green hydrogen is made from plants with MW power suppliers, but steel plants will need GW-powered plants to produce enough hydrogen to meet the requirements of typical steel plants around the world. Although there are plans for GW scale plants in several locations around the world, supply chain issues and concerns about costs have seen several large-scale plants delayed in their construction.

The cost of green hydrogen is also a concern, with current costs around the world varying between USD$4-10 per kilogram. Even at USD$4 per kilogram, the cost of steel is likely to increase more than 50 per cent, meaning the transition to hydrogen will either require tariff protection or subsidies if a steel company wants to survive the transition.

Of course, larger scale hydrogen production is likely to reduce these costs so stalling the construction of larger scale green hydrogen plants further undermines investment into hydrogen-based ironmaking technology. This has caused various experts to take a somewhat pessimistic view about achieving net zero for world steel production by 2050.(2)

Decarbonising on home soil

In the midst of uncertainty about the transition to hydrogen-based ironmaking, Australian ore miners are evaluating how this revolution – or perhaps evolution – will affect the attractiveness of the giant Australian iron ore export industry.

Australian iron ore – and particularly from the Pilbara – is high in gangue minerals which are easily removed in blast furnace technology.

An onsite conveyor belt carries iron ore

Image credit: Aussie Family Living/ 

In the case of the main hydrogen Direct Reduced Iron (DRI) technologies under development, removing the gangue minerals is not so easy and may require the development of electric smelting furnace (ESF) technology. Utilising ESF technology would mean removing gangue minerals in the form of a slag, which can ideally be used as a feedstock into cement production.

The industry has been left with many questions, such as how Australian iron ore producers can adapt to the emerging green iron market and whether they will need to carry out more processing of iron ores before shipping.

Given the abundance of renewable energy to Australian iron ores, another factor under consideration is the feasibility of co-locating, including whether hydrogen plants should be made in close proximity to iron ore mines and if the iron ore can be converted to DRI close to the mines.

Sustainable Mineral Processing and Green Steel Program
These questions and others are being considered by researchers at Melbourne’s Swinburne University of Technology and Australia’s national science agency, CSIRO, who formally joined forces after working together on similar projects and topics for many years.

The partnership between the two organisations is aiming to research and develop new green steel and mineral processing methods to drive the industry towards net zero, as well as guide future demonstrations and industry development.

In early April 2024, the CSIRO and Swinburne partnership secured funding from the Australian Renewable Energy Agency (ARENA) to assist with commercialising a new low carbon route to agglomerating iron ores for furnaces.

The project started as a PhD project at Swinburne before the two organisations joined forces with industry partners to develop the concept.

Initially, the new agglomeration process was designed to reduce the total carbon dioxide from iron production by over ten per cent, but the concept is being adapted to hydrogen-based ironmaking processes for either larger reduction. Promising laboratory results(3) have formed the basis of patents and the new funding from ARENA will allow the project to move to commercial scale testing of the idea.

The driving force behind the development is Dr Suneeti Purohit, who came to Australia as a student with Professor Brooks at Swinburne and is now a scientist at CSIRO. Dr Purohit’s work has already attracted awards nationally, recognising a high level of innovation.(4)

There are a multitude of other projects underway across the country, with ARENA’s April funding announcement resulting in $59.1 million being awarded across 21 research projects that are researching and developing commercialisation activities covering renewable hydrogen and low emissions iron and steel. The funding is being provided to research teams from some of Australia’s top universities, research organisations, start-ups and companies.

The team at Swinburne is also actively working with Calix P/L, an Australian based furnace technology company with a background in developing new low- carbon technology, in their development of a fully hydrogen-based ironmaking process called ZESTY.

The novel process is designed to reduce the carbon footprint of ironmaking to close to zero by using electrically heated kiln technology to provide heat into the process and minimise the use of costly hydrogen in the process. Strong progress has been made at their pilot plant facility in Bacchus Marsh, with a range of ores being successfully converted into DRI at close to commercial grade.(5)

The joint program for Sustainable Mineral Processing and Green Steel is attracting investment from the partners, industry and funding agencies to evaluate both the scientific and economic issues around the green steel transition, whether it be a revolution or an evolution.

Significant innovation and technical excellence will be required to decarbonise the world’s steel industry and Australian researchers are likely to play a significant role.


(1) Three phases to green steel,

(2) Ibid.

(3) Alternative route for magnetite processing for lower carbon footprint iron-making through lime-magnetite pellets containing CaFe3O5,

(4) Suneeti Purohit is helping reduce emissions from steelmaking,

(5) Calix Zero Emission Steel Technology engineering study finds economical green iron solution,

Image credit: Xiangli Li/


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