IKKA-CCUS aims to demonstrate a novel modular crystallization process for CO2 capture based on ikaite formation (CaCO3·6H2O), inspired by natural processes in cold marine environments. The hypothesis is that a membrane-based system using seawater, carbonate chemistry, and flue gas can efficiently precipitate ikaite and convert it into pure calcium carbonate, while achieving scalable and low-energy CO2 capture.
The project will construct and operate a 2-3-container demonstration plant at an industrial coastal site in Denmark. CO2 gas is first absorbed into alkaline seawater, altering the carbonate balance; this CO2-enriched solution is then mixed with fresh, calcium-rich seawater across membrane surfaces, where ikaite precipitates and grows directly on the membrane. The system will be tested with raw, scrubbed, and biogenic flue gas to evaluate performance across multiple sources. Analytical and optimization activities will assess gas capture efficiency, water chemistry, and mineral output. End-users from the paint and plastics sectors will validate the produced CaCO3 solids. Finally, Topsoe and Valmet will develop a roadmap and simulate electrolysis integration for future industrial-scale plants.
The project will deliver proof-of-concept for ikaite-based CO2 capture under real-world conditions, generate >1000 kg of CaCO3 for industrial validation, and provide key datasets for environmental and techno-economic assessments. This will lay the foundation for scalable, decentralized CO2 capture with integrated utilization, aligned with Denmark’s CCUS goals.
