Building materials firm CEMEX and solar solutions provider Synhelion have established what they claim is the world’s first solar clinker at the Very High Concentration Solar Tower of IMDEA Energy in Spain.

This key component of cement is produced by fusing limestone, clay and other materials in a fossil fuel-fired, carbon dioxide-emitting rotary kiln requiring temperatures nearing 1,500° C. The carbon-neutral pilot batch clinker production unit was engineered by connecting the clinker production process with a Synhelion solar receiver delivering temperatures in excess of 1,500° C to heat a gaseous heat transfer fluid and provides the required process heat for clinker production. Carbon emissions generated by the calcination process mix with the heat transfer fluid in the solar receiver system and can be easily harvested from the closed circuit, ensuring that zero CO₂ emissions are released into the atmosphere.

The solar energy-produced clinker was used to make cement and was processed further to manufacture concrete. Following this first successful calcination and clinkerization achieved using solar energy, the companies will next produce solar clinker in larger quantities in pursuit of an industrial scale pilot at a cement plant.