Cables instead of coal: Cement production in the climate transition

Hot rotary kilns, high emissions in cement production

To produce cement, limestone is heated to over 1000 degrees. This way, so-called “burnt lime” is created – a central ingredient, namely the main binding agent in cement. This step is known as calcination, which is essential, but also a real climate culprit: It is not only the combustion of fossil fuels that causes CO₂, but the chemical reaction itself also releases large quantities.

The idea: Replace fire with electricity – climate-friendly cement production

SaltX’s solution almost sounds too good to be true: Instead of heating the limestone with gas or coal, they’re using an electric arc, similar to a welding arc – only on a much larger scale. This technology is called Electric Arc Calciner (EAC). It can reach temperatures equally as high as a rotary kiln, but without flames – and without fossil fuels. If the electricity is generated by renewable energy sources, the calcination process is nearly emission-free.

When industrial power and clean-tech innovation meet

Salt X is a start-up from Sweden, which has specialized in the electrification of industrial processes. With EAC, they have developed a patented technology never seen before. The only thing missing was a partner with industrial expertise to put this technology into practice. This is exactly what thyssenkrupp Polysius brings to the table: Decades-long knowledge of building large plants and the development and integration of new technologies – globally.

One example is polysius^® activated clay. This technology allows a reduction of CO₂ emissions of up to two thirds. The trick:  Part of the cement clinker is replaced by calcined clay – a thermally-activated type of clay which is processed at comparably low temperatures of 880 to 900 °C. In comparison: The usual production of clinker requires much more heat. This can reduce CO₂ emissions by up to 85% per ton of material.

“We perfectly complement each other”, says Lukas Schoeneck, Head of Green Solutions at thyssenkrupp Polysius. “Start-up spirit meets industry knowledge. This way, we’re creating something greater than the sum of its parts. And something that offers a real added value to the world of tomorrow.”

How to turn a vision into reality: The electrification of cement plants

Currently, the two partners are working on a collaborative pilot project. The goal is to integrate the EAC-technology into an actual production environment – not only in cement but also in the limestone industry and in the field of direct air capture (DAC). Especially DAC – the filtering of CO₂ directly from the air – could benefit enormously from the emission-free high-temperature technology.

Lina Jorheden, CEO of SaltX, clarifies this: “Together we can set new standards – and develop production plants that are fully electrified and emission-free.”

This kind of transition certainly isn’t easy. Existing plants have to be modified, power grids have to be adapted, processes have to be re-evaluated. But this is exactly why the partners are counting on modular decarbonization solutions that can be integrated step-by-step. Moreover, the EAC is supposed to be developed in a way that it can be turned on and off whenever needed – a real advantage in comparison to the classic rotary kilns.

Think big, act green – The future of cement production

The vision is clear: Cement plants minus the CO₂ emissions. And that’s no dream of the future. If politics, the economy and science work together, the transition can progress faster than many believe. Because pressure is building up – not only through climate goals but also laws, CO₂ prices, and societal expectations.

“Companies that invest in green technologies early have a clear competitive advantage”, emphasizes Lukas Schoeneck. “And they’re showing responsibility for both people and the environment.”