New Chemical Looping Process Transforms Industrial Waste Into Sustainable Cement Materials

Every year, industrial processes such as steelmaking and coal production produce enormous amounts of waste materials and liabilities that are often difficult to manage and reuse. Researchers at The Ohio State University have developed a chemical looping process that offers a way to turn these materials into valuable resources for sustainable construction while also capturing carbon dioxide and producing clean hydrogen.

Led by Department of Mechanical and Aerospace Engineering Assistant Professor Shang Zhai, who also has a joint appointment at the School of Earth Sciences, the research was published earlier this year in the Energy and Environmental Science journal. The study, titled "Looping-accelerated CO₂ mineralization for cost-competitive cementitious materials and hydrogen" outlines a chemical looping process that transforms bulk industrial waste streams, including steel slags and off-spec coal ashes, into valuable materials for more sustainable cement production.

Unlike conventional direct aqueous carbonation, which can be slow and costly, this approach accelerates carbonation kinetics by four to nine times under ambient conditions.

The new process produces two valuable materials: carbonaite-rich solids and high-purity amorphous silica. These materials can be blended to partially replace traditional energy and carbon dioxide intensive cement in concrete. This creates new uses for industrial waste that otherwise goes to landfill.

"Because this chemical looping process achieves an order-of-magnitude boost in carbonation kinetics alongside very attractive technoeconomics, it provides a highly scalable path forward for circular industrial waste management," Zhai shared.

"Building on our successful laboratory proof-of-concept, our team is now actively seeking resources and partners to scale up this process from the gram scale to the kilogram scale, and ultimately to a continuous multi-ton commercial pilot scale."

Beyond the research's environmental benefits, the new process also has promising potential for lower costs. Through the acceleration of carbonation reactions, it reduces processing costs to approximately 15-20% of what is associated with traditional direct aqueous carbonation. This approach is particularly attractive for larger scale industrial applications, with the potential to achieve commercial payback periods of just one to two years.

Outside of presenting, students took full advantage of being in Antalya. Students were able to swim in the Mediterranean, teach locals American style line dances, and explore Belek and Pamukkale.