Of the 55 million metric tons of steel slag generated yearly in the EU, an estimated 52% is currently underutilized and often ends up in landfills or directed to other low-value applications. As EAFs and direct reduced iron (DRI) replace BOFs, granulated blast furnace slag (GBS) availability declines. EAF slag has remained underutilized due to its chemical composition and high metal and impurity content, the company said. 

“Our process enables high-performing cement products from materials that would otherwise be treated as waste. With this innovation, we're proving that decarbonization and circularity can go hand in hand, and at scale,” said Oscar Hållén, chief executive officer of Cemvision.

The patent-pending beneficiation process upcycles slag into SCM which is on par with, or outperforms, ground granulated blast furnace slag (GGBS), according to third-party testing. Of the 25 to 40% iron oxide in EAF slag, Cemvision’s slag valorization process can extract and recover an estimated 99%. The iron and other valuable materials such as chromium can be returned to steel producers and reintroduced to the steelmaking process with a circular material loop. 

The company said the output material helps secure feedstock of its Re-Ment Massive and Rapid and can be used as a clinker replacing SCM to ensure and extend circularity in the cement industry. 

Cemvision has worked with metallurgical research institute Swerim to develop this innovation. Together, they said they have proven both technical feasibility and commercial potential. 

“The chemistry and performance of the resulting materials are not only viable, they're promising enough to set a new benchmark for what green cement can be made from,” said Elsayad Mousa, senior researcher in metallurgy at Swerim.