Turning steel waste into circular cement

Can this modular tech cut concrete's massive carbon footprint?

Spotted: Concrete is responsible for 1.5 per cent of the UK’s total greenhouse gas emissions, and the bulk of these are generated during production of cement – the substance that binds concrete. Blast furnace (BF) slag, a by-product of steel production, has long been incorporated into concrete mixtures to reduce the volume of cement required. However, with the steel industry decarbonising and switching from fossil fuel BFs to electric arc furnaces, less BF slag is available, and the new slag can’t be mixed into concrete in the same way. Enter Cocoon.

The London-based startup has developed a new technology that allows it to convert the by-products created by electrified furnaces into a near-identical replacement for traditional BF slag. The idea began when Dr. William Knapp, Cocoon’s Chief Science Officer, was looking into industrial waste streams and realised the importance of improving the circularity of two of the globe’s highest-emitting industries – steel and concrete. Alongside fellow co-founders Eliot Brooks and Freddie Scott, Dr. Knapp created Cocoon to do just that.

Cocoon’s modular technology, which is roughly the size of a shipping container, is easily scalable and integrates into the end of existing steel-making processes without requiring disruptive and expensive retrofits. The technology’s two-step, carbon-capturing process then transforms steel waste and CO2 emissions into a supplementary cementitious material. Customers should be able to replace between 30 and 50 per cent of the cement they use in concrete mixtures with Cocoon’s material, which would allow them to quickly cut down on emissions.

Talking to Springwise, CEO Eliot Brooks explained: “Over the next 40 years we will build double the amount of infrastructure as there is in the world today. Much of this is critical to the energy transition, improving quality of life, and catering to growing populations. All of it will require more steel and cement.” With Cocoon’s solution, manufacturers of these two key materials will be able to drastically lower their carbon footprint, even as production ramps up.

Cocoon plans to demonstrate its technology at the Material Processing Institute in the UK, before bringing its technology on to a commercial steel plant.

Written By: Matilda Cox