Displaying items by tag: Limestone calcined clay

India: JK Lakshmi Cement has partnered with the Society for Technology and Action for Rural Advancement (TARA) to integrate calcined clay technology into its operations in order to commence production of limestone calcined clay cement (LC3). United News of India has reported that the producer says that this type of composite cement reduces the product's clinker factor by 50% and its carbon footprint by 40%.

JK Lakshmi Cement said "This partnership will be a game-changer for the cement industry, giving impetus to its efforts in mitigating emissions, combating climate change and bringing a holistic change in the surrounding communities to create sustainable livelihoods in large numbers."

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.

Benelux/France: Cementir Holding has introduced its Futurecem limestone calcined clay cement into the Benelux and French cement markets. Futurecem cement applies Cementir Holding’s patented processes to substitute over 35% of clinker in cement with limestone and calcined clay, preserving the cement’s strength and quality while reducing its carbon footprint by 30% compared to ordinary Portland cement (OPC).

Cementir Holding previously rolled out Futurecem cement in Denmark in 2021. In 2022, it plans to launch InBind high performance concrete (HPC) and ReCover ultra-high performance concrete (UHPC) to expand its range of HPC and UHPCs using Futurecem technology.

Eddy Fostier, managing director of Cementir Holding’s Belgian subsidiary CCB, said “Thanks to the joint efforts of the group and CCB teams, Futurecem technology is the main pillar for CCB’s low carbon transition within the Group roadmap. This product technology is matching customer needs, highlighted through a specific survey carried out across the most relevant market areas and applications.” Fostier concluded “I’m fully convinced that Futurecem will play a relevant role in the decarbonisation of the construction industry, where cement and concrete are essential building materials both in the present and in the future.”

Denmark: Aalborg Portland Cement says that the market ‘warmly welcomed’ its new FUTURECEM calcined clay cement in 2021. The product has reached its sales expectations for the year and is now nearly sold out for 2022. The company says that its plan to ramp up FUTURECEM production to replace 50% of grey cement production at its Rørdal cement plant is on track.

Parent company Cementir Holding says that the success of FUTURECEM rests on four pillars, namely its suitability for intended applications, targeted communication, close dialogue with concrete producers and the entire value chain and strategic partnerships with leading construction clients. It said “The lesson learned is that the market needs thorough information about new products and its industrialisation to rely on and implement them in place of conventional products.” The group added that its experience in Denmark paves the way for limestone calcined clay technology rollouts in other markets in line with its sustainable roadmap towards 2030.

Charah Solutions has been steadily building up its fly ash distribution business in recent years with an eye on the supplementary cementitious materials (SCM) market. This week it opened the third of its new series of SCM grinding plants, at Oxnard in California, US. The unit sticks out because it is focusing on grinding natural pozzolans. The plant will receive natural pozzolan by truck and rail and then use Charah’s patented grinding technology to produce pozzolan marketed under its MultiPozz brand. The previous plants in this series mentioned natural pozzolans but this is the first to promote it explicitly.

The change is potentially telling because global demand for granulated blast furnace slag (GBFS) outstrips supply. Both performance benefits and environmental regulations are pushing this. It’s a similar situation for fly ash, also driven by trends to close coal-fired power stations in some countries. As Charles Zeynel of SCM trading firm ZAG International explained in the March 2019 issue of Global Cement Magazine, “...volcanic pozzolans are a potential SCM of the future. This is gaining traction, but it’s slow progress at the moment. This will be the answer for some users in some locations.”

The problem though is that natural pozzolans are down the list of preferred SCMs for their chemical properties after silica fume, GBFS and fly ash. The first is expensive but the latter two were traditionally cheap and easy to obtain if a cement or concrete producer had access to a source or a distribution network. Natural pozzolans are very much subject to variations in availability.

It’s no surprise then that Charah is promoting natural pozzolans in a Californian plant given that state’s environmental stance. It’s unclear where Charah is sourcing their pozzolan from but they are not the only company thinking about this in the US. Sunrise Resources, for example, is working on the environmental permits for a natural pozzolan mine near Tonopah in Nevada. As it described in its company presentation, California and Nevada are the most affected states in the fly ash supply crisis because they are, “...at the end of the line when it comes to rail deliveries from power stations in central and eastern USA.” It also estimated that California used 0.9Mt of pozzolan in its cement production of which about 90% is fly ash. The state produced 9.6Mt in 2015. Other companies are also mining and distributing natural pozzolans in the US as the website for the National Pozzolan Association (NPA) lists. Although, if this line-up is comprehensive, then the field is still fairly select. Most of these companies are based in the west of the country.

One last thing to consider is that various groups are tackling a potential future lack of SCMs for the cement industry by making their own pozzolanic materials through the use of calcined clay. These groups include the Swiss-government backed LC3 project and Cementir’s Futurecem products. Using clay should bypass the supply issues with natural pozzolans but the cost of calcining it requires at the very least an investment to get started.

As concrete enthusiasts often point out, a variant of pozzolanic concrete was used by the Romans to build many of their iconic structures, some of which survive to the present day. To give the last word to the NPA, “What is old is new again: natural pozzolan is back!” If environmental trends continue and steel and coal plants continue to be shut then it might just be right.

Cuba: The University ‘Marta Abreu’ of Las Villas (UCLV) has started operating a 7t/day limestone calcined clay cement plant. The unit will be run by the Geominera del Centro Company, according to the Cuban News Agency. Building materials produced at the plant will be used locally.

Fernando Martirena Hernández, director of the Centre for Research and Development of Structures and Materials (CIDEM), said it was the first plant producing low carbon cement in the world. The project is a collaboration between the university and the Swiss Agency for Development and Cooperation as part of the LC3 project. Similar plants are planned for 18 countries including India, China, Indonesia, Thailand, Guatemala, Mexico, Ecuador, Colombia, Peru, Ivory Coast, Cameroon and Senegal.

India: Swiss, Indian and Cuban researchers have come together to develop limestone calcined clay cement (LC3), which can help reduce the carbon dioxide emissions of cement by almost 30%.

"The LC3 project is an example of scientific and technical collaboration between Switzerland and India. The innovative cement production process on which these institutions are working is of great economic and environmental significance," said Switzerland Ambassador to India Linus von Castelmur.

The LC3 is a synergetic hydration of clinker, calcined clay and crushed limestone to achieve the performance required from commercial cements, with clinker factors as low as 0.40. It also costs less than traditional types of cement.

"The testing and application phase is over, now it has to pass through standardisation committee before it is accepted by the industries. The research that has been done will not be patent protected but available to everyone," said Castelmur.