Cocoon develops a rapid cooling, low-capex, modular process that retrofits into existing electric arc furnace waste handling to convert steel slag into a high-performance supplementary cementitious material (SCM). The company’s product matches traditional SCM performance while reducing the embodied CO2 of concrete by up to 40%. Cocoon has piloted its technology at a major steel mill, completed third-party validation of its material in concrete applications, and established an R&D facility and concrete testing lab in London. With demand for SCMs growing roughly 6–7% annually and supply tightening as legacy industrial sources retire, Cocoon targets faster, capital-efficient deployment by co-locating at steel plants to minimize logistics and leverage existing operations. The company is scaling hiring across the U.K. and U.S. and aims to deploy more than 50 sites in the U.S. and Europe (targeting 50 sites by 2035) following its U.S. commercial demo.

Total raised

$20M

Funding rounds

2

Latest round

Series A

Latest activity

Mar 2026