French researchers make iron using urine and sunlight

The work, published in the Journal of Cleaner Production, comes from researchers at the CNRS-linked Laboratory of Physics and Chemistry of Nano-Objects, INSA Toulouse and the University of Toulouse. The scientists said they tested two routes to generate ammonia from urea: direct solar pyrolysis and decomposition accelerated with crushed plant seeds rich in urease, with both methods producing iron.

For investors, the immediate impact is not a near-term threat to global steel volumes. The researchers themselves say the process is too constrained by the limited global supply of urine to power large-scale mills, and would instead be suited to small local micro-foundries in sunny regions.

That limitation matters because it keeps the technology in the realm of decentralized, artisanal production rather than a substitute for blast furnaces or direct-reduced iron plants that drive the industrial market. But it also underscores a broader point: decarbonization in metals is not being left to one pathway, and capital is likely to keep flowing toward a mix of hydrogen-based, electric, recycling and niche low-input processes.

The timing lands as steel and iron markets remain sensitive to supply disruptions and cleaner-production policy. Ukraine has halted iron exports, while iron prices have strengthened in September as freight and premium costs eased, restoring some profitability for imported ore. At the same time, producers such as Vale and Rio Tinto remain exposed to swings in iron ore pricing, while U.S. steelmaker Nucor has emphasized its ability to pass through raw-material costs when demand is firm.

For miners and steelmakers, the Toulouse experiment is unlikely to change earnings in the short term. But it adds to the pressure on the sector to prove it can cut emissions without blowing up costs, energy demand or feedstock security — a test that is becoming more important as buyers, lenders and policymakers push harder on industrial decarbonization.

The bigger investor takeaway is that the low-carbon steel race is still open-ended. Green hydrogen remains the headline solution, but the French team’s work shows that future metal production may also include smaller, locally powered systems that could matter for resilience, rural manufacturing and niche industrial use.