Co-reactive Puts EIC Accelerator Money on Carbon-Storing Cement

Cement makers have long cut the carbon in their product by mixing in waste from two other industries: fly ash from coal power stations and granulated slag from blast furnaces. Both supplies are shrinking as those plants close or convert. Co-reactive, a 2024 spin-off of RWTH Aachen, wants to replace them with a powder made by reacting captured CO2 with ground silicate rock or steel slag. The company says each tonne of the result stores about 330 kilograms of CO2.

The EIC Accelerator selected Co-reactive at its 1 October 2025 cut-off for blended finance, and CORDIS files the project under the EIC Challenge on the acceleration of advanced materials development and upscaling. CORDIS records grant agreement 101297983, CO-REACTIVE, with an EU contribution of €2,241,879 from 1 June 2026 to 31 May 2028. CORDIS gives no figure for the total project cost, and no EIC equity amount has been published.

Cement is running out of its cheapest substitutes

The project summary in CORDIS sets out the case: cement causes 8% of global CO2 emissions, each tonne of Ordinary Portland Cement releases about 850 kilograms of CO2, and the supplementary cementitious materials the industry uses to replace part of the clinker are "now in short supply due to the phase-out of coal-fired power plants and the decarbonization of steelmaking." Anna Stetter, an investment manager at HTGF, said when the seed round was announced that fly ash prices had in some cases quadrupled over two years, according to HTGF and Trending Topics.

Regulation adds pressure from the other side. The project names the EU emissions trading system and the carbon border adjustment mechanism, which the European Commission applies to cement, among other sectors, in its definitive regime from 1 January 2026. The project argues that these rules are "driving up the cost of carbon compliance", and presents its material as an answer to both pressures at once: a substitute that does not depend on coal or blast furnaces, made from slag that European steelmakers already produce.

How the process works

The company's website and an nbau report of July 2025 describe the same chain. Magnesium or calcium silicates, such as olivine, or slags from metallurgy are milled, mixed with water and fed with CO2 into a tubular reactor at high pressure and temperature. The CO2 ends up bound as carbonates alongside amorphous silica, which reacts in cement as a pozzolan. A filter press and a rotary dryer turn the slurry into a fine powder the company calls CO-SCM. The CO2 can come from cement works, waste incinerators, biogas plants or direct air capture, and the plant can sit next to the source.

CORDIS calls the reactor "the world's first TUBULAR CO-Reactor for CO2 mineralization", which is the company's own description in its application. The difference from the established substitutes is where they come from: fly ash and granulated slag are by-products whose supply depends on power stations and blast furnaces, while CO-SCM is made on purpose, in what the HTGF release describes as a continuous process designed as a drop-in for existing cement production lines.

Co-reactive is not alone with the idea. Holcim says it has used Paebbl's mineralised CO2 powder, Rebond, in a concrete slab for the foundations of a logistics centre in southern Germany, with 15% less cement than the reference mix. Co-reactive took part in the 2024 cohort of the same group's Holcim MAQER Ventures accelerator; the accelerator's page does not say that it placed or won anything, and no supply agreement between the two has been announced.

The figures are the company's own

The performance numbers in public all come from the company or from articles based on its information. The nbau report gives a strength activity index of 99 to 106% at 25% replacement of CEM I, comparable with blast furnace slag. The Carbon Drawdown Initiative, which backs the company, wrote in July 2025 that mortars with 25% CO-SCM matched the strength of pure Portland cement in pilot tests and that the process converts up to 95% of the CO2. No test report, certificate or independent laboratory result could be found in a search on 4 November 2026.

The storage figure also varies by source. CORDIS and the company's site give 330 kilograms of CO2 per tonne; Radio Neandertal reported "up to 300 kg" when the plant opened; nbau quoted 330 kilograms and, for olivine-based material, up to 500 kilograms. CORDIS adds that three tonnes of CO-SCM are made "for every ton of CO2 avoided", which matches the 330-kilogram figure: three tonnes at 330 kilograms each bind about one tonne.

From pilot reactor to demonstration plant

The Carbon Drawdown Initiative put the pilot reactor at 10 tonnes a year in July 2025. In January 2026, HTGF and Trending Topics reported that the company would expand to a continuous demonstration plant of about 1,000 tonnes a year by the second quarter of 2026, followed from 2027 by first-of-a-kind plants with industrial partners, which neither names.

The demonstration plant step happened on time. North Rhine-Westphalia's economy minister Mona Neubaur opened it in Erkrath on 27 April 2026, with the chief executive of NRW.Bank, Gabriela Pantring, attending, according to Mittelstandsmagazin NRW; Radio Neandertal reported the opening on 28 April with a planned output of about 1,000 tonnes a year. The company's own news page dates its item on the opening 7 July 2026. Neither article gives the investment cost, staff numbers or the plant's output so far, and Mittelstandsmagazin noted that the company gives no exact details of its chemical process.

Co-reactive also says it has joined GeoCRM, a research project funded by the EU's regional and Just Transition funds with thyssenkrupp MillServices & Systems, the VDEh-Betriebsforschungsinstitut, the FEhS building materials institute and RWTH Aachen. The project aims to recover critical raw materials from steel slag and carbonate what remains; its budget is not stated on the company's page.

A young company that has moved fast

The register records a string of changes in two years. The articles of association are dated 26 January 2024, and Bremen and Kleineberg were entered as managing directors on 27 March 2024, according to register data republished by webvalid. On 10 October 2025, nine days after the EIC cut-off, the shareholders resolved to raise the share capital by €12,203 to €37,203 and to move the seat from Düsseldorf to Erkrath. The Wuppertal register took the company over as HRB 36552 on 12 February 2026, with Willi Peter as a third managing director. No insolvency notice appears in either record, and no filed accounts with revenue, equity or staff figures could be read for this article.

The research base is documented. RWTH Aachen announced on 2 February 2024 that Co-Reactive, from its Aachener Verfahrenstechnik institute, was one of three winners of the 2023 Innovation Award, quoting Bremen: "As a result of our research, we can now store CO2 as a mineral solid." The team was funded through EXIST research transfer, a programme of the federal economy ministry, and nbau reports that it won the start-up category of the DGNB Sustainability Challenge 2025.

What the EIC project has to show by 2028

The EIC announced on 17 February 2026 that it had selected 61 companies out of 121 interviewed for proposed support of €467 million, per the ATHENA grant office's republication of the EIC's notice. Co-reactive's own announcement does not state its grant or equity amounts. The project started in June 2026, so CORDIS shows no report or deliverable yet, which is normal at this stage.

1. Continuous tubular reactor at demonstration scalePlant openedOpened 27 April 2026 per Mittelstandsmagazin NRW; no output figures published.
2. Material storing 330 kg of CO2 per tonneCompany claimSources give 300, 330 and up to 500 kg; no independent measurement found.
3. Cement performance at 25% replacementCompany dataStrength index of 99 to 106% per nbau; no published test report.
4. Industrial plants with partners from 2027Not yet duePartners unnamed; no customer or offtake agreement announced.

The reporting is based on publicly available sources, listed below.