Showcasing what’s possible: clay calcination in Ghana

UNVEILING CBI’S CALCINED CLAY PLANT AT TEMA

Fuller supplied the groundbreaking calcined clay plant, with a capacity of 1,200 tons per day—or over 400,000 tons per year—making it the world’s largest clay flash calciner. The project is based on the company’s flash calcination technology and includes full color control and product heat recuperation, reducing energy costs to 50% of those for clinker production lines. The resulting process emits just 10% of the CO2 emissions of clinker production.

A HIGH-QUALITY PRODUCT

With its high-quality calcined clay, CBI Ghana’s LC3 cements can deliver substantially higher compressive strength from 7 days onwards than OPC cement, along with enhanced durability. This allows a significant fraction of the clinker in cement to be replaced without impacting performance.

However, not all clays are equally viable for calcination. This highlights the importance of testing locally available clays before investing in a clay calcination plant. At Fuller’s Dania laboratory and R&D center in Denmark, the company has extensive facilities to assess a clay’s suitability for thermal activation, including bench- and pilot-scale calcination, color control, emissions analysis, grindability testing, and reactivity and strength testing of blended cement containing a calcined clay sample.

CERTIFYING THE NEW CEMENT

Central to bringing Supacem LC3 to market was the establishment of a national certification framework for LC3 cement, led by the Ghana Standards Authority (GSA) as the key institution responsible for developing and approving the new standard.

"This landmark achievement followed two years of collaboration between Ghanaian institutions — including KNUST, the University of Ghana, and the Building and Road Research Institute — alongside international universities and laboratories, including EPFL, with technical support from Professor Karen Scrivener”, explained CBI Ghana’s Kobby Adams.

The resulting standard, GS PAS 5:2024, adopted in May 2024, makes Ghana the first country in the world to establish a national LC3 standard, permitting cement products with as little as 35% clinker.

“The standard – and work done to achieve it – paves the way for the widespread use of this more sustainable, locally-sourced cement,” Adams continued.

GRINDING THE FINAL PRODUCT

Fuller also provided a UMS 4.6 x 14.0 ball mill for final cement grinding. Operating in closed circuit with an O-Sepa™ N 2500 third-generation separator, the mill is designed to produce 120 tonnes per hour of finished cement at a Blaine fineness of 380 m²/kg. The two-compartment mill uses step lining in the first compartment for coarse grinding and corrugated lining in the second for fine grinding, with material flow between the two controlled by the adjustable diaphragm.

A closed-circuit configuration ensures tight control over product quality and energy efficiency. The O-Sepa separator's variable-speed rotor allows operators to adjust product fineness as required. Automatic control loops governing feed rate and proportions, separator airflow, and mill diaphragm temperature, alongside manual control of the separator rotor speeds and damper positions, enable consistent operation from the central control room.

A SUCCESSFUL PROJECT

All process and product quality performance guarantees have been met, ensuring the pathway to a greener future is both successful and commercially viable. “Our Supacem LC3 cement is already being delivered to customers nationwide, offering lower CO2 emissions, excellent strength development, and enhanced durability,” said Kobby Adams of CBI Ghana. “This addresses a real and urgent need in the Ghanaian market. By producing a significant portion of our own cementitious material locally, we reduce the impact of clinker shortages and deliver a more reliable cement supply for retailers and builders across the country.”

The success at CBI Ghana points to calcined clay's transformative potential not only to reduce cement-related carbon emissions but also to enable cement production in regions where limited local limestone reserves make traditional clinker production economically or geographically challenging. With clay deposits widely available across cement-producing regions worldwide, the potential for deployment is substantial. Together with Fuller’s installation of Europe’s first industrial-scale calcined clay facility at Vicat’s Xeuilley plant in France, the Tema project for CBI Ghana is now proving that this potential can be turned into a commercial reality.