JOHANNESBURG (miningweekly.com) – A green hydrogen breakthrough in Namibia is opening the way for decarbonised steel using iron-ore of considerably lower grade.

In an electrically powered hydrogen rotary kiln, 80 t of Australian iron-ore has been converted in climate‑neutral fashion into direct‑reduced iron (DRI) using ore with an iron content of around 56%, which is well below the typical 70% – and without the usual energy-intensive pelletising.

With this, Sustainable Steel from Australia and Germany – the SuSteelAG consortium – is paving the way for a sustainable value chain linking Australia, Namibia, and Germany from iron production and refinement to green steel, which, who knows, may even make up the bodywork of your next car, with the help of Namibia’s abundant solar resources. 

Last year, SuSteelAG, led by Federal Institute for Materials Research and Testing (BAM), embarked on its mission to decarbonise steel production using hydrogen, including when working with lower‑grade ores.

Now, the first industrial‑scale pilot test has been successfully completed to convert the iron-ore climate‑neutrally into DRI.

The steel industry accounts for around 7% of global CO₂ emissions; transforming it is therefore a central lever of the energy transition.

Coordinated by BAM, the project is developing a hydrogen‑based direct‑reduction process that expands the resource base available for green steel production in being able to use lower‑grade ores.

Until now, climate‑neutral steel production has only been feasible using premium ores with an iron content of roughly 70%.

These ores, however, are scarce and expensive worldwide. Moreover, existing processes require the use of a shaft furnace, which in turn demands cost‑ and energy‑intensive pelletising of the ore.

For the first time, untreated Australian iron-ore with a comparatively low 56% iron content has been processed into DRI at industrial scale at Namibia’s Oshivela site, where project partner HyIron Green Technologies operates the innovative hydrogen rotary kiln.

For the campaign, the 80 t of iron-ore was supplied by Australian mining and technology company Fortescue, also a SuSteelAG partner.

The German industrial furnace manufacturer TS Elino GmbH was primarily responsible for designing and constructing the rotary kiln.

Prior to the industrial trial, BAM had extensively studied hydrogen‑based iron reduction at laboratory scale and derived the optimal operating parameters for the large‑scale process.

Based on these findings, the Oshivela plant refined the Australian ore into iron under climate‑neutral conditions and with a throughput of five tonnes an hour.

“We have now reached a scale that is highly relevant for industrial production and demonstrated that hydrogen‑based direct reduction of lower‑grade ores can be operated economically – an essential step toward accelerating green steel production in Germany and beyond. This also means that green steel production need not be constrained by the limited availability of premium ores,” Christian Adam of BAM, who coordinates the international SuSteelAG consortium, stated in a media release to Mining Weekly.

The next step will be to ship the refined iron from Namibia to Germany. Salzgitter Mannesmann Forschung GmbH will investigate how the refined iron can best be integrated into existing industrial processes to eventually produce climate‑friendly steel for cars and other key products.

RWTH Aachen University (Advanced Mineral Processing Technologies Research and Teaching Unit - AMR) will investigate how Australian ores with lower iron content can be further optimised for direct reduction.

In addition to the companies already mentioned, the SuSteelAG consortium includes HyIron GmbH, Fraunhofer Institute for Surface Engineering and Thin Films IST, Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Heidelberg Manufacturing Deutschland GmbH, and Hansaport.

SuSteelAG is funded with €4.5-million under the seventh Energy Research Programme of the German Federal Ministry of Research, Technology and Space.

The innovative hydrogen rotary kiln operated by HyIron Green Technologies was supported by the German Federal Ministry for Economic Affairs and Energy.