By Peter Roberts
Along with steel production, the manufacture of cement is among the most economically critical and at the same time most polluting of industries.
Both products are vital and yet both contribute billions of tonnes annually to carbon dioxide emissions that are raising global temperatures and threatening humanity.
But paths to decarbonise both products are becoming increasingly apparent.
Australian listed Calix Ltd is a leader in decarbonising cement with its LEILAC-2 project which is focused on scaling the company’s CO2 mitigation technology for cement and lime.
Being developed at HeidelbergCement’s Hannover plant, the project follows a successful pilot at a plant at Lixhe in Belgium.
LEILAC (Low Emissions Intensity Lime And Cement) is a direct separation carbon capture technology that has been developed since 2013 with €12 million in funding from the European Union’s Horizon 2020 research and innovation program.
The Calix process engineers the existing process flows of a traditional calciner indirectly heating the limestone via a special steel reactor.
This allows pure CO2 to be captured as it is released from the limestone, with furnace exhaust gases kept separate.
Other than a new kiln, the process does not involve any additional processes or chemicals.
Now Calix has announced CEMEX, which operates 65 cement plants with production capacity of 93 million tonnes annually, has joined the consortium developing the LEILAC-2 demonstration plant.
LEILAC-2 is a 100 ktpa plant that will separate 20 per cent of a regular plant’s process emissions – around 100 ktpa of CO2 – all backed by a further €16 million funding by the EU.
The Calix carbon capture and storage process is one of a number of decarbonising routes being developed including an amine-based industrial scale CCS unit at Norcem’s Brevik plant and a HeidelbergCement supported oxyfuel project.
Others are attempting to reduce the need for clinker through the use of calcined clays, or proposing solar reactors or electric-powered kilns.
The other major challenge facing cement is developing recycling systems to produce aggregates or new cement material.
At a recent innovation in industrial carbon capture conference the Calix technology was described as the ‘Tesla’ of industrial carbon capture.
We are by no means at the point of declaring that cement can be part of a low carbon future, but with Calix, the future might just be a step closer.
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