The partnerships are aimed at developing and implementing new methods to reduce carbon emissions and improve environmental performance across the steel value chain.

Rio has committed to invest US$10 million with Baowu in research over the next two years, which is the next step in advancing the partnership formed between the two and Tsingshua University in 2019.

Rio's investment will fund the joint establishment of a Low Carbon Raw Materials Preparation R&D Centre, which will initially prioritise the development of lower carbon ore preparation processes.

This will include creating two ore preparation pilot plants, one to use biomass and the other exploring using microwave technology. The investment will also support work on carbon dioxide utilisation and conversion at the China Baowu Low Carbon Metallurgical Innovation Centre, which is a Baowu-led open platform for advancing metallurgical technologies to support the low-carbon transformation of the steel industry.

Rio CEO J-S Jacques said the investment was an important step in the partnership.

"We have been able to identify research and development projects which have the potential to significantly reduce the carbon emissions associated with existing steelmaking processes, as well as developing technologies for the future of steelmaking to support the transition to a low-carbon economy," he said.

"The initial priority areas identified by the partnership for investment show the value of working together to share resources and utilise the strengths of the respective teams to make progress towards a low-carbon steel value chain."

The memorandum of understanding with Nippon will see the two companies explore decarbonisation technology, including integrating Rio's iron ore processing technology and Nippon's steelmaking technology to establish an innovative steel manufacturing process with low carbon emissions.

The two companies have agreed to a partnership model in line with the long-term and complex nature of the transition to carbon neutrality for the steel industry, which allows the partners to take a long-term view to enable the pursuit of new and promising technologies as the global steel transition evolves.

"Nippon Steel has been an important partner for our business with a very long history and we are delighted to be able to extend our partnership to work together to reduce carbon emissions across the steel value chain," Jacques said.

Rio and other major miners have been under pressure to reduce scope 3 emissions, which are the emissions of its customers.