Diversified miner Rio Tinto has successfully demonstrated the effectiveness of its low-carbon iron-making process, known as BioIron, using ores sourced from mines in Pilbara, Australia.

The demonstration has been carried out during the past 18 months in a small-scale pilot plant in Germany.

A project team from Rio Tinto , sustainable technology firm Metso Outotec , and the University of Nottingham’s Microwave Process Engineering Group carried out extensive testing of the BioIron process.

With the process proven, Rio Tinto now plans to develop a larger-scale pilot plant to help decarbonise the steel value chain.

BioIron involves the use of raw biomass, as an alternative to metallurgical coal, as a reductant and microwave energy. This will convert iron ore to metallic iron in the steelmaking process.

Rio Tinto anticipates BioIron to support near-zero CO₂ steelmaking. It is also expected to result in net negative emissions upon linking with carbon capture and storage.

Global engineering, project management and professional services firm Hatch conducted a comprehensive and independent technical review confirming the potential of the BioIron process.

Rio Tinto chief commercial officer Alf Barrios said: “Finding low-carbon solutions for iron and steelmaking is critical for the world as we tackle the challenges of climate change. Proving BioIron works at this scale is an exciting development given the implications it could have for global decarbonisation.

“The results from this initial testing phase show great promise and demonstrate that the BioIron process is well suited to Pilbara iron ore fines. BioIron is just one of the pathways we are developing in our decarbonisation work with our customers, universities and industry to reduce carbon emissions right across the steel value chain.”

Rio Tinto plans to test the BioIron process on a larger scale at a specially designed continuous pilot plant that will have a capacity of one tonne per hour.

The mining firm is currently scouting suitable locations for the construction of the pilot plant, the design for which is currently under progress.

The company is also undertaking a benchmarking study of biomass certification processes to address the difficulties around the use of biomass supply.