Key Benefits

  • Environmentally-friendly clinker substitute
  • Excellent colour control
  • Energy-efficient process
  • Support of pilot lab to build your perfect plant

Calcined clay – the environmentally friendly clinker alternative

Clay is a naturally occurring material found almost everywhere around the world. With the right treatment, it makes a perfect SCM and can be used to replace up to 40% of the clinker in your product. With our clay calciner system, you maximise your return on your investment. With lower capital costs as compared to a new clinker line, you get an energy efficient process that delivers a high quality product and can maximise your substitution rates.

Clay calciner system

The process begins with the dryer crusher, designed specifically to manage the high moisture content of your clay. Material is then fed to the 2-stage preheater/calciner system where it is preheated and activated in the calciner. 

A cyclone at the outlet of the calciner separates the gas and material. The temperature and other process conditions can be tightly controlled. This allows for a consistent operation, resulting in uniform product quality and emission control. Furthermore, because the stable process delivers a highly consistent product, you can substitute more clinker as compared to calcined clay produced in a rotary kiln.

Clay calciner preheater layout

Our flash calciner system costs less to set up than a rotary kiln and is more energy efficient by approx. 20% as compared to a rotary kiln. Furthermore, it produces highly reactive clay that can be used as a clinker substitute in the range of 30 – 40%, resulting in a huge CO2 reduction for the finished cement product. In contrast, only 15 – 25% substitution can be achieved with product produced in a rotary kiln because the calcined clay is less reactive and therefore less suitable as a clinker substitute.

Colour control to obtain grey blended cement

By applying the right settings and conditions during activation and cooling, we have developed a unique, patent-pending process to achieve the standard grey cement colour in your clay. This ensures end users will be happy with the look of the product, as well as its performance.

Our efficient calciner system minimizes fuel consumption, maximizing the recuperation of heat from the product.
Any fuel type typically used in a traditional clinker system - including waste fuels - can be fired in the calciner.

Confirm your clay’s viability with our full chemistry and mineralogical testing as well as clay reactivity analysis

Clay’s suitability as a clinker substitute depends on its chemical content (in particular, its oxide and mineralogical content), how amorphous its structure is, particle fineness, strength development and emissions.


We will help you confirm that you have a suitable clay source as well as the right equipment design to process it. Our laboratory testing services include full chemistry as well as clay reactivity analysis. A pilot scale system is also available to produce calcined clay in a larger scale to allow a full quality and strength test of the blended cement product if desired.

Retrofitting an existing kiln

If you have an unused kiln available, we can develop a site-specific concept for a system that produces calcined clay. This will have a lower capital cost than a new clay calciner system, but also limits the potential clinker substitution to ~20% due to quality.

Benefits of a calciner vs a kiln to activate clay

You can activate clay in a rotary kiln – but the results simply aren’t good enough to achieve high levels of clinker substitution.

  • Higher quality product due to more consistent activation
  • Higher mix percentage of calcined clay into blended cement
  • Lower fuel and maintenance costs
  • Greater fuel flexibility for burning waste fuels
  • Smaller footprint for a new system
  • Lower capital cost for a new system

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