Mining group Rio Tinto is developing innovative new technology to deliver low-carbon steel, using sustainable biomass instead of coking coal as a reductant in the steelmaking process, as an option potentially cost-effective to reduce carbon emissions from industry.
Rio Tinto has spent 10 years developing a laboratory-proven process that combines the use of raw, sustainable biomass with microwave technology to convert iron ore into metallic iron during the steelmaking process.
The patent-pending process, one of many avenues the company is pursuing in an attempt to reduce emissions in the steel value chain, is currently being further tested in a small-scale pilot plant.
If these and larger scale tests are successful, it is possible that over time this technology will be scaled up commercially to process Rio Tinto’s iron ore fines.
Simon Trott, Managing Director of Rio Tinto Iron Ore, said: “We are encouraged by the initial test results of this new process, which could provide a cost effective way to produce low carbon steel from our Pilbara iron ore.
“Over 70% of Rio Tinto’s Scope 3 emissions are generated when customers process our iron ore into steel, which is essential for urbanization and infrastructure development as global economies decarbonize.
“So, although it is still in its infancy and there is still a lot of research and further work to be done, we want to further explore the development of this technology.”
Rio Tinto’s process uses plant matter known as lignocellulosic biomass, instead of coal, primarily as a chemical reducer. Biomass is mixed with iron ore and heated by a combination of biomass-released gas and high-efficiency microwaves that can be powered by renewable energy.
Lignocellulosic biomass includes agricultural by-products such as wheat straw, corn stover, barley straw, sugar cane bagasse and specialty crops.
Rio Tinto researchers are working with the multidisciplinary team from the Microwave Process Engineering Group at the University of Nottingham to further develop the process.
Using raw biomass in Rio Tinto’s process could also avoid the inefficiencies and associated costs of other biomass-based technologies that first convert biomass into charcoal or biogas.
Picture: Rio Tinto
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