Cement works in Höver

Not only CEMEX and partners are working to solve the Herculean task of creating sustainable cement. In the cement works of Höver, not far from Hannover, the company Holcim is testing out an innovative technology intended to decarbonize the building material. There, Holcim, together with the two partners Cool Planet Technologies, specializing in CO₂ separation, and research institute Helmholtz-Zentrum Hereon, has installed a CO₂ capture plant based on an innovative membrane technology. The first step entails the gathering of practical experience with CO₂ capture. After a few weeks of operation with the test system, the first results were very positive. “We were able to observe a good separation rate and comparatively high purities,” rejoiced Stephan Hinrichs, plant manager at Holcim.

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The next phase of the research and development project that will span about two and a half years was planned to start in August 2022. A one-year test phase, during which a long-term operation of the plant will be examined, is scheduled to begin in September of next year. If good results are confirmed, the plant will be further expanded step by step. In the final expansion stage, around 90 percent of CO₂ emissions would be captured. The resulting very pure, liquid CO₂ can be stored or further processed. The goal of the Holcim team around Stephan Hinrich is to demonstrate that carbon capture can also be economically efficient on a larger scale.

Carbon2Business set on pure oxygen

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Holcim has already received a grant out of the EU Innovation Fund for a project in Lägerdorf called Carbon2Business. Funding has been provided for the construction of a new kiln line in the cement works of Lägerdorf, located on the West coast of Schleswig-Holstein. A prototype that uses oxyfuel technology is being developed that should accelerate the decarbonization of cement production on an industrial scale. The CO₂ captured in Lägerdorf is to serve as a raw material for other industries.

Instead of ambient air, pure oxygen is fed in for the combustion processes. The required oxygen is to be produced along with the hydrogen from electrolysis. The oxyfuel method generates highly pure CO₂ gas in the cement kiln, which can then be separated and converted to methanol by reaction with hydrogen. With this, the site can avoid the emission of about 1.2 million tonnes of CO₂ per year. In Lägerdorf, like in Rüdersdorf, the green fuel as a market-ready product will help advance sustainability in the cement industry.

Magnesium-based cement

Concrete production accounts for around six percent of man-made CO₂ emissions worldwide. Researchers at Empa in Switzerland are striving to change this. They are currently working on a CO₂-negative concrete. The basis for the eco-concrete is a magnesium-based cement. The raw material is sourced from regions where the magnesium-containing mineral olivine naturally occurs. The mineral is mainly found deep in the earth’s mantle. However, if it is transported to the earth’s surface by volcanic activity, for example in Norway, it can be mined. During the production of cement from olivine, carbon dioxide is added to the raw magnesium silicate material. Since only part of the resulting material is fired in an additional processing step, less CO₂ is released during the combustion than was previously consumed. The end balance is therefore negative. The product has been named MOMS, short for “magnesium oxide derived from silicates.”

Author: Niels Hendrik Petersen