Rio Tinto is working to remove coking coal from its steelmaking process, replacing it with plant matter for a cost-effective and sustainable alternative.
As Australia exported about 182 million tonnes of metallurgical coal in 2019-20 at a value of $35 billion, the removal of coking coal from the steelmaking process would significantly alter the Australian mining landscape and wider economy.
Rio Tinto, for example, exported 77.8 million tonnes of iron ore from the Pilbara region of Western Australia in the March quarter of 2021.
The World Steel Association (WSA) has said it takes a ratio of two parts iron ore, one part metallurgical coal and 0.575 parts steel scrap to create crude steel.
As metallurgical coal is made of about 60 to 70 per cent coking coal (the remainder being PCI coal), Rio Tinto’s March iron ore exports would have called for roughly 25 million tonnes of coking coal in the steelmaking process.
Rio’s tests to revolutionise the steelmaking process are currently in small-scale pilot plants.
Rio Tinto Iron Ore chief executive Simon Trott said success in this area would drastically reduce Rio Tinto’s emissions.
“More than 70 per cent of Rio Tinto’s scope 3 emissions are generated as customers process our iron ore into steel, which is critical for urbanisation and infrastructure development as the world’s economies decarbonise,” Trott said.
“So, while it’s still early days and there is a lot more research and other work to do, we are keen to explore further development of this technology.”
The plant matter – known as lignocellulosic biomass – is made of wheat straw, corn stover, barley sugar and sugar cane bagasse, among other things.
The research has taken place over the past 10 years and is now a patent-pending process.
Trott acknowledged there was still a way to go in refining the process and commercialising it at scale.
“We know there are complex issues related to biomass sourcing and use, and there is a lot more work to do for this to be a genuinely sustainable solution for steelmaking,” Trott said.
“We will continue working with others to understand more about these concerns and the availability of sustainable biomass.”