Rohrdorfer launches pilot plant for low-CO2 cement production

Raw clay is activated ("tempered") through thermal treatment in the plant. The aim of the plant is to research tempered clays, as they can be used as a lower-CO₂ alternative to clinker, the main component of cement. They are thus a central component of Rohrdorf's decarbonisation roadmap. The pilot plant was created as part of a pilot project funded by the German Federal Ministry for Economic Affairs and Energy and the EU and will receive funding of up to €8.65 million due to its innovative potential. The project started in October 2023 and will end in December 2026.

Low-energy and low-emission operation thanks to innovative plant concept

The pilot plant utilises the existing waste heat from the clinker production line and was therefore built directly next to the rotary kiln. The utilisation of kiln waste heat and the use of the specially designed flash calciner make it possible to temper the clays using very little primary energy. The exhaust gases generated during operation are fed into the existing exhaust gas treatment system of the clinker production line after leaving the plant. This means no additional emissions are generated.

The plant was planned and built by the French plant manufacturer Fives FCB, in collaboration with Rohrdorf's Net Zero Emission team. The construction phase lasted approximately six months. The maximum production volume is 50 tpd of tempered clay.

Sophisticated process engineering

By the end of 2026, the Net Zero Emission team will investigate the ideal composition of the raw clays and optimise the thermal treatment processes. In addition, different grinding finenesses and the use of different aggregates will be tested. The result is that the tempered clay will serve as a CO₂-saving replacement for clinker while meeting all standards for cement production. "With the systematic research of tempered clay technology in the production process at the Rohrdorf plant, we are doing pioneering work in the cement industry," says Markus Judendorfer from the Net Zero Emission team. "A particular challenge is to optimise the product while simultaneously further improving the plant's energy efficiency. Our initial results from the initial phase are very satisfactory."

CO₂ avoidance through less clinker in cement

Trials with various raw clays and process parameters are currently planned until mid-2026. Building on these trials, a large-scale plant will be built in the future that will enable significant CO₂ savings. "The potential for CO₂ savings amounts to a total of 60%. Almost half of this can be avoided thanks to tempered clays. The new pilot plant is therefore an important step on our path to CO₂-neutral cement production, which we are targeting for 2038," explains Dr. Christopher Ehrenberg, Technical Director of the Rohrdorf Cement Division.

Read the article online at: https://www.worldcement.com/europe-cis/09072025/rohrdorfer-launches-pilot-plant-for-low-co-cement-production/