Rio Tinto went to its customer's steel mill to capture the carbon its ore generates

Rio Tinto and Shougang have brought online in China an industrial-scale trial plant that captures up to 10,000 tonnes of CO₂ a year from blast furnace gas — and turns part of it back into an input for making steel.

Rio Tinto and Shougang Group, one of the world's ten largest steel producers, announced on September 28, 2026 the commissioning of an industrial-scale trial plant for capturing carbon from blast furnace gas, installed at the Jingtang base in China. The unit treats up to 3,000 cubic meters of gas per hour and has the capacity to capture up to 10,000 tonnes of CO₂ a year. Part of that CO₂ is being converted into syngas, which goes back into the steelmaking process and reduces the amount of new carbon needed to make steel. The plant is the next step after a smaller facility commissioned in 2024, within a staged program set out in a 2022 memorandum of understanding. The agreement also covers low-carbon sintering and blast furnace and basic oxygen furnace optimization. The companies indicate that using the mill's own waste heat can lower the cost of capture. The commercial relationship between them began in 1996, with the first shipment of Pilbara iron ore to Shougang.

The central point is carbon accounting. For an iron ore miner, most of the emissions associated with its product do not happen at the mine, but when the ore becomes steel in the customer's blast furnace — what the GHG Protocol calls scope 3. Cutting diesel and electricity in its own operations is necessary, but it moves a small fraction of the total footprint. Anyone who wants to tackle the big volume has to work inside the steel mill, and that is what Rio Tinto is doing. The choice of the blast furnace as a target is also instructive. New routes, such as hydrogen-based direct reduction, get more attention, but most of the world's steel still comes out of blast furnaces, many of them recent and with decades of useful life ahead, especially in China. Technology that reduces emissions from existing assets has an immediate market; technology that depends on replacing the entire mill has a future market. The project's design shows how to take a lab technology to commercial scale without betting everything at once: first a small plant in 2024, now an industrial trial unit, and only later a possible broad rollout. Each stage generates cost and performance data that determine whether it is worth continuing. Blast furnace gas is a dilute stream, with CO₂ mixed with nitrogen and carbon monoxide, which makes separation energy-intensive. Using the mill's waste heat to power the capture tackles exactly that cost. And converting CO₂ into syngas for reinjection changes the economic logic: captured carbon stops being a waste product that needs geological storage and becomes an input that replaces part of the coke or coal purchased. It is worth keeping the scale in perspective. Ten thousand tonnes a year is small next to the emissions of a large blast furnace, which reach millions of tonnes annually. It is a learning plant, not mass decarbonization, and the companies have not disclosed the cost per tonne captured.

Steelmaking is among the industrial sectors that emit the most CO₂ in the world, and iron ore is its main raw material. For miners such as Rio Tinto, Vale and BHP, pressure from investors and customers over scope 3 emissions is likely to turn into a commercial advantage for those who offer, along with ore, concrete paths to cut carbon at the steel mill. Technical partnerships with customers, once rare in the purely commercial relationship between miner and mill, are becoming part of the sales strategy. For Brazilian professionals, the message is direct: the mining or process engineer who understands the customer's metallurgy, not just the ore's chemical specification, becomes more valuable. And for steelmaking in Brazil, which also runs mostly on blast furnaces, capture with reuse of CO₂ as an input is a route worth following, because it can reduce emissions without requiring plants to be replaced entirely.