Scientists turn corn waste into flame retardant

Scientists have found a way to turn a leftover from corn processing into a fireproofing material, cutting demand for a dwindling element. Researchers working on the EU-backed ScaleAmP project have extracted phosphorus from corn steep liquor, a syrup-like byproduct of starch factories, and turned it into a non-toxic flame retardant. Tests show the green chemical can coat fabrics and foams as effectively as traditional phosphorus-based additives, which are mined from finite rock deposits.

The push for a renewable source of phosphorus is accelerating because the world’s mineable reserves could run low within decades. Agriculture already consumes about 90% of extracted phosphorus for fertilizer, leaving only a trickle for industrial uses like fire safety. Rising geopolitical tensions around phosphate rock—supplies are concentrated in just a few countries—have pushed researchers to hunt for alternatives. Corn steep liquor, a waste stream from wet-milling corn into starch or ethanol, is produced in millions of tonnes annually and has largely been sold as animal feed at low value, making it a ready-made feedstock.

Lab trials indicate the new retardant can be blended into polyurethane foams at 5–10% loading without weakening the material, and it meets strict fire-safety standards used in furniture and building insulation. The team estimates that diverting just 1% of Europe’s annual corn steep liquor output could supply enough phosphorus to coat 200 million square metres of foam. The next step is pilot-scale production, followed by certification for commercial use, which the researchers hope to finish within three years.

If successful, the breakthrough could ease pressure on phosphate mines and cut greenhouse-gas emissions from fertilizer production, because recycling phosphorus from waste streams uses far less energy than mining. It would also give starch producers an extra revenue stream from a low-value byproduct, turning potential pollution into a valuable green chemical.