Veolia Research & Innovation has successfully developed a circular carbon fiber economy in its Limay research center. A complex but key mission in view of its extensive use in all industries.
The latest Airbus A350 is 53% manufactured using carbon fiber parts.
Carbon fiber is riding high. Known since 1950, its use has exploded since the 1990s. And for good reason: it is used to create composite materials which are simultaneously fine, light, flexible and very resistant. Particularly popular in cutting edge industries such as aeronautics and space, it is also used in the automotive and sports industries. It is estimated that 8.6 million metric tons of carbon fiber are produced every year.
However, composite materials are very difficult, if not impossible, to recycle. The obstacle is above all a technical one – the problem being how to separate the carbon fiber from the polymer resin that surrounds it without damaging and so losing its technical properties. Because in most cases, even if the polymer resin has reached the end of its life, the carbon fiber is still largely usable.
In the absence of a viable circular model, composite materials have until now mostly ended up in landfills. The reserve of this type of waste is huge and likely to grow in the future. Notably with the increase in the number of aircraft needed to meet the hike in air traffic. In the next twenty years or so, end-of-life aircraft will have far more composite material than today's do. The latest Airbus A350 for example is 53% manufactured using carbon fiber parts. A solution that will give a new lease of life to this waste has to be found – and very soon.
Extracting carbon fiber
This is what Veolia Research & Innovation is working on at the Limay Research Center (Yvelines).
The waste is sorted and characterized according to its condition and composition, then processed. As things stand the most mature technique is pyrolysis. It removes the polymer resin to recover the carbon fiber – which is then impregnated with a new polymer and can be (re)used - as new - in any industrial sector.
Less expensive and less polluting to produce than its original version, recycled carbon fiber has a very promising future in terms of meeting the exponential demand from industry. Veolia is currently focusing on the first reuse of carbon fiber, but researchers are already studying the possibility of repeating the operation several times over without it losing its properties.
This method opens up a whole new field of possibilities for recycling end-of-life parts used in the transportation, sports and leisure and energy sectors. But also for recovering production offcuts. Another colossal reserve - as evidenced for example by Airbus, which every year produces 100 metric tons of composite material offcuts in its factory in Saint-Nazaire.
VEOLIA Library - Christophe Majani d'Inguimbert