By Anthony Harrup

MEXICO CITY -- Mexican cement maker Cemex SAB has joined forces with Swiss synthetic fuels developer Synhelion SA to use solar heating to make cement, a step it sees contributing to its long-term carbon-reduction goals.

Cemex plans to start a pilot test at an existing cement plant by the end of 2022, using Synhelion's solar heating technology that has achieved the necessary high temperatures.

Cemex and Synhelion expect to invest between $6 million and $10 million in the pilot test, said Davide Zampini, Cemex's head of global research and development.

"Thanks to the technology that Synhelion is developing we can bring the solar heat up to 1,500 degrees celsius. In the process, we can also capture the CO2, and that fits perfectly well into the process of the synthetic fuel," he said.

The use of solar heat will complement other measures that Cemex, one of the world's biggest building materials companies, is taking to achieve its carbon-reduction targets.

Cemex will meet its goal of cutting CO2 emissions by 35% from 1990 levels in 2030 with existing technologies, and will be looking to innovations like those of Synhelion to reach its 2050 target of producing carbon-neutral concrete, said Vicente Saiso, director of sustainability at Cemex.

The pilot represents the first industrial test of the process heat technology for Synhelion, a spinoff of the Swiss Federal Institute of Technology.

"It's a very important step for us," Synhelion chief executive Gianluca Ambrosetti said of the cement project. "This is our first venture where we will use our technology beyond fuel synthesis."

Synhelion is working with Italian energy company ENI SpA to make methanol from carbon dioxide, water and methane using solar energy. It also has agreements with German airline Deutsche Lufthansa AG and the Zurich airport operator, Flughafen Zurich AG, to support the development and eventual marketing and promotion of sustainable fuels.

Write to Anthony Harrup at anthony.harrup@wsj.com