Innovative clay-based low carbon cement

As the European first industrial-scale flash calciner to enter operation, Vicat’s Argilor facility is pioneering the shift to lower-carbon cement. Using local clay sources and innovative processing technology, the French materials company Vicat leads in activated clay-based cement that helps meet France’s RE2020 building regulations.

Key facts

• Official project name: Argilor Xeuilley cement plant
• Location: Xeuilley, France
• Project stage: Operational
• Sector: Cement
• Total project investment: €60 m
• Customers: Construction companies, architects, ready-mix, precast, masonry
• Jobs: 9,990 employees for Vicat group globally
• Capacity: 120,000 tonnes per annum (tpa) of activated clay.
• Key milestones and dates:
  • Project first announced in April 2021
  • Received public funding from ADEME in June 2021
  • Started construction in October 2022
  • Started production in October 2024

Solid foundation for innovation

Vicat is a long-standing family-run company founded in 1853 with operations in 12 countries and 16 integrated cement plants with a production capacity of 40 million tonnes of cement per year. It has the stated intention of upholding its legacy in the cement and construction business, with decarbonisation the inevitable next step in its journey and has committed to reach carbon neutrality by 2050 on its full value chain.

As widely recognised in the cement industry, reaching zero emissions will require carbon capture in the long-term. However, other incremental technologies are available in the shorter term with fewer obstacles to overcome. Vicat has decided to implement these with the Argilor project so that it can start offering alternative products to the market more quickly.

“There are different levels to reduce CO2 in cement production and what’s important to note is that for each of these levels, different investment is needed. Some projects have an initial investment of a few million euros to some tens of millions of euros, and then there are capital-intensive projects, for example, CCS, which come with a much higher risk and often a blockage” – François Avet, Head of Low-clinker Cement Development, Vicat

Vicat built the Argilor activated clay production facility with a 120,000 tonnes per annum (ktpa) capacity in its Xeuilley cement plant in northeast France. It is the European first industrial-scale flash calciner, an industrial furnace that rapidly heats, dehydrates (or ‘calcines’) and cools clay in a matter of seconds to create a pure and highly reactive activated clay.

This activated clay can be used as a substitute for the carbon-intensive cement component clinker, reducing the amount needed and, by doing so, avoiding the emissions of close to 50 ktpa of CO2 at the facility. Vicat has a target of 25% net CO2 reduction per tonne of cement from a 2015 baseline across the group by 2030.

“We have a clear strategy, but we are pragmatic and able to adapt. We don’t want to advertise projects which may never happen in the future; on the contrary, we are able to realise projects, sometimes even through just our own funds as far as they are economically viable” – François Avet, Head of Low-clinker Cement Development, Vicat

For Vicat, activated clay is a highly promising Supplementary Cementitious Material (SCM) to partially substitute clinker as it is widely available and provides good concrete performance when used at high rates.

Knock-on effects of evolving adjacent industries

Looking ahead, Vicat could see that as coal power plants decline and as the steel industry evolves from thermal to electric, there would be global shortages of fly ash (from coal) and blast furnace slag (from steel), the conventional additive materials that can be used alongside clinker to make cement. At the same time, demand for cement from around the world is increasing. Raw limestone is the most well-known substitute.

“We already use limestone a lot, but when you go above 10% to 15% of substitution, then you cannot maintain exactly the same performance as a conventional cement.” – François Avet, Head of Low-clinker Cement Development, Vicat

Affordable SCM for today’s challenges

The French RE2020 building regulation introduced in 2020 acted as a strong driver for establishing the project. By setting maximum limits on embedded carbon emissions in new buildings, RE2020 was designed to incrementally promote the use of low-carbon materials and a decarbonised construction industry.

Thanks to this, Vicat was sufficiently confident in the project’s viability and that the French market would turn to cleaner construction materials to remain compliant. The company noticed supportive market signals even before the regulation entered into force in early 2022, as customers started requesting lower-carbon alternatives.

The project was only possible because the clay found at the nearby Xeuilley quarry is of high enough quality to turn into activated clay. If the company had to open another dedicated quarry in France, it would have taken up to 10 years of permitting process – or 15 years if it were in Switzerland.

Thanks to locally-sourced clay that is less energy-intensive to process than clinker, the company became able to offer low-carbon cement blends at a comparable price, creating the right solution for the right market at the right time.

“In terms of economics, the objective was to produce cement with activated clay that remains economically viable compared with what was already being produced using conventional materials” – François Avet, Head of Low-clinker Cement Development, Vicat

Building confidence in flash calciner technology

Argilor’s flash calciner is a new technology for the production of activated clays in large quantities (they have been producing activated clay using a rotary kiln in Brazil since 2009) and as the name suggests, speeds up production time. Vicat sought out an equipment supplier with deep production expertise that, together with internal know-how, enabled them to optimise the process.

Many pilot tests on a smaller scale were needed to give confidence in the technology, to ensure that the resulting clay would meet the quality specifications and to meet the target clinker substitution levels set internally.

In addition to dealing with the risk of a new technology, using alternative fuels to run the equipment is another innovation that Vicat has successfully managed.

Securing investment – €60 m – was also a critical step for Vicat. A public grant of around €13 m from the French Agency for the environment (France 2030 mechanism) partly relieved the burden, while the rest of the investment was borne by the company. The shareholder structure (which is largely family-controlled), coupled with a strong vision, played a role in driving the internal decision for this project.

“The family-controlled shareholder structure of Vicat brings a lot of stability to the group.” – François Avet, Head of Low-clinker Cement Development, Vicat

Standards remain a barrier

Additionally, slow evolution of the cement standard EN 197-1 – which specifies the composition of cement, including authorised proportions of clinker, activated clay and limestone – has hampered the introduction of blended cement containing activated clay to the market.

It was eventually revised in May 2021 to allow new low-carbon cements with activated clay, but still prevents higher clinker substitution rates (above 50%) with limestone and activated clay. Standards are still a barrier to the introduction of activated clay cement in certain countries, such as in Egypt, where Vicat operates one integrated plant.

“The standard upgrade in Europe was a good achievement. But we would have loved it to go further and to remove some of the blocking criteria, for example, today in Europe, you are not allowed to put less than 50% clinker into cement. It’s technically viable and could meet the requirements of the market but it’s not allowed. Through ongoing project at France Ciment, the industry in France is working to accelerate the adaptation of the standard to the arrival of these new additions” – François Avet, Head of Low-clinker Cement Development, Vicat

Learnings from global projects

Besides Argilor, Vicat has been running an activated clay production facility in Brazil based on rotary kiln technology since 2009.

Rotary kilns and flash calciners are the two main options for producing activated clay, with the tried-and-tested rotary approach also useful in repurposing existing clinker kilns while flash calciners tend to activate clay more efficiently.

“In Brazil, we use activated clay in all our cements because our clients really like it.” – François Avet, Head of Low-clinker Cement Development, Vicat

Vicat expects to draw valuable learnings from both of these technologies to assess which configuration is the best for future projects, in addition to valuable and unique expertise on the behaviour of activated clay cements which it can share with their customers.

“This is a great advantage compared to potential new players who may come into the market in five years: we already know how to produce it and how to use it” – François Avet, Head of Low-clinker Cement Development, Vicat

The need for visibility and certainty as technology neutrality

From Vicat’s point of view, long-term visibility and certainty are perhaps the most essential public support the industry could get to transform. Even if the outlook is not one Vicat or the industry would like, visibility and certainty still enable decision-making and the ability to progress.

Certainty and demand stemming from the RE2020 building regulation set the stage for the Argilor project and further legislation providing clarity will be particularly critical for enabling the development of capital expenditure-intensive projects like carbon capture and storage. In case the RE2020 building regulation is considered for the EU Construction Products Regulation (CPR) under redaction, it would be worth using the standard LCA instead of the tailor-made one used so far as to maintain a technology and material neutrality.

Despite the policy uncertainty or row-back that can be experienced in some countries, Vicat is remaining agile to always adapt its strategy without losing the objectives.

Vicat cites the EU’s Carbon Adjustment Border Mechanism as a positive step in equalising the global playing field and hopes that its implementation will lead to strict controls of material components entering Europe.