PHNX Materials has developed a process to strip sulfur and aluminum from coal fly ash pulled from landfills so the ash can be used as a cement substitute in concrete mixes. By prepping low‑quality ash, PHNX aims to unlock a larger supply of fly ash for concrete makers, who can use up to 30% ash to replace cement and lower carbon intensity. The company plans to sell cleaned ash to concrete producers and recover sulfur, aluminum and other compounds for sale to relevant industries; it is also exploring extraction of rare earth elements. PHNX’s approach targets material saved in the roughly 843 fly ash landfills in the U.S. and responds to shrinking ash availability after coal plant closures reduced coal’s share of U.S. electricity from 51% to 15%. The startup frames its work as a scalable way to decarbonize concrete production, noting that each ton of cement produced in the U.S. emits about 0.8 tons of CO2.

Total raised

$3M

Funding rounds

1

Latest round

Seed

Latest activity

Apr 2025