Facing bricks by brand new Limburg factory absorb tonnes of CO₂

Carbonation is the chemical process whereby two residual products, in this case steel slag and CO₂, create high-quality building materials. The process is as follows: the calcium-rich steel slag is ground into an ultra-fine powder, dried, and then water is added until the desired porosity is achieved. The mixture is poured into brick moulds, and the bricks are placed in a sealed chamber where 30% CO₂ is pumped in, allowing them to harden. During the curing process, the CO₂ permanently bonds with the calcium-rich bricks. In one year, this is equivalent to the amount of CO₂ absorbed by 114,000 mature trees.

Not only is the final product CO₂ negative, but its production process is also CO₂ neutral. The company’s solar panels and wind turbine largely supply the green electricity needed to power the plant. The heat required for the drying process comes from residual heat generated by nearby brick kilns. CO₂ is sourced from surplus emissions from the ports of Antwerp and Ghent. Additionally, the waste mountain is decreased by reusing steel slag, and the facing bricks are designed to be dismantleable and thus reusable.