African cement producers have confirmed their interest in calcined clay over the last month with two new projects. The big one was announced last week when FLSmidth revealed that it had received an order from CBI Ghana. This follows the launch of a Limestone Calcined Clay (LC3) project in Malawi in mid-March 2022 in conjunction with Lafarge Cement Malawi.
FLSmidth says that its order includes the world’s largest gas suspension calciner system and a complete grinding station. The kit will be installed at CBI Ghana’s plant near Accra in the south of the country. The new clay calciner system is expected to substitute 30 - 40% of the clinker in the final product, resulting in a reduction of up to 40% CO2/t of blended cement compared to Ordinary Portland Cement (OPC). Overall the equipment manufacturers reckon that the grinding plant will reduce its CO2 emissions by 20% compared to its current output. There has been no indication of how much the order costs but CBI Ghana expects energy and fuel savings, as well as lower overheads from clinker imports.
The public announcement of the Ghana project was also foreshadowed by the visit of Professor Karen Scrivener to the Ghana Standards Authority in February 2022. This was significant because Scrivener is the head of the Laboratory of Construction Materials at the Ecole Polytechnique Fédérale de Lausanne (EPFL) and has been one of the key instigators of the LC3 initiative since the early 2000s. Other calcined clay cements are available such as Futurecem or polysius activated clay (see below) but LC3 is arguably the most famous given its promotion in developing countries.
The Malawi project is at a much earlier stage. The government launched the public private partnership LC3 project in mid-March 2022 in conjunction with Lafarge Cement Malawi and Terrastone, a brick manufacturer. The Ministry of Mining is currently developing a memorandum of understanding with the Gesellschaft für Internationale Zusammenarbeit (GIZ), a Germany-based development agency. India-based Tara Engineering has also been linked to the scheme.
One thing to note about the Malawi project is that it is the first calcined clay project in the cement industry based in East Africa. All the other African ones are based in West Africa. The other two projects in this region are run by Turkey-based Oyak Çimento and its subsidiary Cimpor. The first of these is a 0.3Mt/yr calcined clay and a 2400t/day cement grinding production line that was commissioned in mid-2020. This plant is based at Abidjan in Ivory Coast. The second is a new plant that Germany-based ThyssenKrupp Industrial Solutions is building for Oyak Çimento at Kribi in Cameroon. This unit has a 720t/day calcined clay and a 2400t/day cement production capacity and it will use the supplier’s ‘polysius activated clay’ technology. ThyssenKrupp’s involvement came to light in early 2020 and commissioning was scheduled for late 2021. However, no update on the state of the project has been issued so far in 2022.
As the above examples show, Sub-Saharan Africa has at least one live calcined clay plant, two plants are being built and there’s one more at the development stage. This puts the region neck-and-neck with Europe, which has a similar mixture of current and developing projects. This column has been covering the wider trend of the growing usage of various types of blended cements recently, particularly in Europe and the US, with slag cements, Portland Limestone Cement (PLC) and more. With PLC, for example, note the transition of another two North American cement plants to PLC this week alone. As for calcined clay cement, it is fascinating to see the focus move to a different part of the world. Several commentators have predicted that the future looks set to be dominated by blended cements using whichever supplementary cementitious material (SCM) is most available for each plant. The growth in calcined clay confirms this view.
Global Cement is researching clay calcination use in the cement industry for the next edition of the Global Cement Directory. Email This email address is being protected from spambots. You need JavaScript enabled to view it. with any information on new industrial and research installations.
