Producing steel and cement creates 14% of global CO2 emissions, and mountains of landfilled waste. Cement only makes up around 10-15% of a concrete mix, but accounts for ~90% of its emissions. Without urgent decarbonization of both sectors, any future we build will blast past 1.5°C warming. Luckily for us, Cocoon’s technology solves for both—and is now backed by $5.4M in fresh funding.

As TechCrunch explains in a recent article on Cocoon, “Slag is the molten runoff created while producing steel in a traditional blast furnace. The material has been prized as greener cement alternative for creating concrete, the Earth’s most abundant human-made material. The runoff is facing supply chain issues, however, as the steel industry looks to greener methods of production.

Increasingly, steel producers in the U.S. and Europe are turning to electric arc furnaces (EAF), which are smaller, more energy efficient and run off of electricity, rather than coal. Cocoon is a new startup built on the belief that greener steel production and the creation of concrete slag doesn’t have to be an either-or proposition.”

Cocoon’s solution is “e-slag,” a processed bi-product of more energy efficient steel production that serves as a cement alternative. Cocoon’s technology integrates into existing steel production workflows, making low-carbon cement alternatives while permanently storing CO2.

The recent $5.4 million in pre-seed funding comes from Wireframe Ventures, Celsius Industries, Gigascale Capital and SOSV. The new funding will enable Cocoon to build an R&D facility in London while initial tests are ongoing. Brooks told TechCrunch that he hopes Cocoon’s technology will be integrated into a pilot plant at some point in late-2025.