FIC-Fighters’ scientific scaling strategy aims to master CO₂ capture with maximum precision.
If you were to visit the pilot plant at the University of Seville, where the valorisation of phosphogypsum (PG) through FIC-Fighters’ NaOH Route is being investigated, the first thing you would see upon entering would not be a complex industrial emission source or an industrial stack, but something far more ordinary: a commercial CO₂ cylinder connected to the carbonation reactor. It might seem like a contradiction, doesn’t it? A project born to capture industrial emissions… supplied by synthetic gas distributed in cylinders?
The answer is not a paradox: it is the direct application of one of the most fundamental principles of scientific methodology. And the reasoning behind it says a great deal about how knowledge is rigorously built before scaling a technology into a real-world applicable solution.
The cylinder: a scientific instrument, not a limitation
In research, controlling variables is fundamental. To understand exactly how portlandite or katoite reacts with CO₂ (at what rate, with what efficiency, under what pressure and temperature conditions) you need a gas of known and stable composition. The commercial CO₂ cylinder provides exactly that: a reference standard. An instrument that allows reaction kinetics to be isolated before introducing the complexity of a real mixed gas with variable composition and industrial impurities.
Without clean data, obtained using pure commercial CO₂, any subsequent result would be impossible to interpret. It is, as one might say, the training before the big match: mastering the reaction in its purest form is the prerequisite for being able to face, later, the variability and impurities of real industrial emissions.
Currently, both pilot plants at the University of Seville (processing 70 kg of PG/day) and at Tharsis Mining (processing 1 tonne of PG/day) are designed to work with high-purity CO₂. This is a strategic engineering decision: isolating the reaction kinetics is key to defining the optimal conditions for producing calcium carbonate that meets commercial purity standards. This “baseline” is essential: without it, it would not be possible to assess the real impact of industrial impurities in later stages of development.
Today’s cylinder is the bridge to tomorrow’s stack.
The next step: CIUDEN takes the chemistry into the industrial environment
While the University of Seville and Tharsis Mining optimise the reaction with pure CO₂, the Fundación Ciudad de la Energía (CIUDEN), headquartered in Ponferrada (León), leads the transition towards the use of real industrial gases. Its role in FIC-Fighters is crucial: to translate the process from a controlled laboratory environment into a viable industrial solution.
CIUDEN is an industrial research centre specialising in CO₂ capture and utilisation technologies. Its specific mission in the project is to replace the commercial CO₂ cylinder with real industrial exhaust gases, always based on a rigorous intermediate step: to characterise industrial combustion gases, in order to later simulate their compositions in the laboratory before working with gas streams from real industrial stacks.
What has CIUDEN found so far?
CIUDEN has characterised the gaseous effluents from eight key industrial sectors: cement, refining, and chemical industries and glass furnaces, among others. Preliminary results point to the cement sector as the most promising candidate: its CO₂ exhaust gases show concentrations of between 400 and 520 g/Nm³, significantly higher than those of other sectors.
The real technical challenge is not the capture of CO₂ itself, but the tolerance of FIC-Fighters’ process to the impurities present in those gases: sulphur oxides (SOx), nitrogen oxides (NOx), suspended particles… Real industrial gases are not pure, and these impurities can affect both the reaction and the quality of the products obtained. For this reason, CIUDEN acts, at this stage, as a stress-testing bench: they simulate the most demanding scenarios of real industrial stacks by using controlled synthetic gas mixtures (synthetically created at their testing facilities, at a scale of 1 to 5 kg/h). This step is critical for technology development: it allows the gas pre-treatment systems and reactor residence times to be adjusted before any larger-scale implementation. The question is not simply whether the reaction works; the operational limits that will make the technology robust and reliable in any industrial environment are also being defined.
The logic of the scale-up: three steps, three certainties
FIC-Fighters’ strategy with respect to CO₂ capture follows a very clear scale-up architecture, leaving nothing to chance:
- Step 1 — Master the chemistry with pure gas (commercial CO₂): the goal is to establish the kinetic baseline of the process with high-purity CO₂ at both pilot plants, University of Seville and Tharsis Mining. This is the work currently underway.
- Step 2 — Validate process robustness with synthetic mixtures (CIUDEN): simulate at lab scale the most demanding industrial gas scenarios to identify the operational limits of the process. This work is also underway.
- Step 3 — Beyond FIC-Fighters: integration with real stack gases: direct connection to an industrial source of CO₂ is the next horizon, beyond the current scope of the FIC-Fighters project. The knowledge generated in steps 1 and 2 will be the scientific foundation that makes this third step possible.
Scope note: Throughout FIC-Fighters, the carbonation stage operates exclusively with pure CO₂ from commercial cylinders (step 1) and with synthetic gas mixtures prepared in the laboratory (step 2). Integration with real gas streams from industrial emission sources is not an objective of the current project: it is the next project. FIC-Fighters is building the scientific knowledge that will make it viable.
Upon completion of FIC-Fighters, we will have the kinetic and operational parameters needed for the technology to make that leap. That is the real value of the work being done now with pure commercial CO₂.
A strategy that transforms the business model
Connecting the process to CO₂ from an industrial stack radically changes both the cost structure and the market positioning of FIC-Fighters in two simultaneous dimensions:
- Eliminating CO₂ supply costs: the gas no longer needs to be purchased. Emissions currently released into the atmosphere by industrial facilities become a zero-cost process input.
- Generating carbon credits: by permanently fixing CO₂ into mineral structures (calcium carbonate), the process can generate carbon credits. These can help emission-intensive industries meet their regulatory obligations under the European Emissions Trading System (ETS), creating an additional revenue stream that significantly improves the viability of the business model.
This dual dimension (cost reduction + value generation through CO₂ capture) is what sets FIC-Fighters apart from a conventional waste management solution. It places the technology within the category of carbon capture and utilisation (CCU) technologies: one of the fastest-growing fields in Europe’s industrial transition.
Today’s cylinder establishes the knowledge that makes tomorrow’s stack possible.
Key References
- Cárdenas-Escudero, et al. https://doi.org/10.1016/j.jhazmat.2011.09.045
- Romero-Hermida, et al. https://doi.org/10.1016/j.jcou.2017.01.002
- CapturaCO2, S.L. (2012). Procedure for CO₂ and SO₂ Capture. Spanish patent no. ES2392280. Spanish Patent and Trademark Office.
- European Commission. (2024). European Critical Raw Materials Act. Regulation (EU) 2024/1252. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202401252