Recycling is critically important to the future of carbon fiber as a replacement for both steel and aluminum. Some have even argued that the composite material will not reach its full potential if the industry fails to come up with a way to cost-effectively recycle. So imagine the interest in work being done by a group of UK researchers who believe they have uncovered a cheap but effective method for reclaiming carbon fiber waste.
A study recently published by researchers at the University of Nottingham suggest that a fluidized bed process for reclaiming carbon fibers from discarded materials can reduce fabricating costs when designs call for carbon fiber stiffness rather than strength. The recycled material would obviously not be suitable for all applications, but it would be significantly less expensive in applications for which it is suitable.
Cutting the Cost of Recycling
The major barrier of recycling carbon fiber is the same barrier that prevents the material from being a complete replacement of steel and aluminum: cost. Recycling carbon fiber waste using a thermal decomposition process requires high heat. As such, it is expensive. Grinding carbon fiber waste is a less expensive method of recycling, but it limits the use of the recycled product. Researchers at the University of Nottingham say their process is the best of both worlds.
They developed a fluidized bed process that separates carbon fibers from plastics. The resulting material can then be reconstituted into aligned fibers or converted into carbon fiber mats using a technique similar to a process for making paper. Astoundingly, their process can recover carbon fiber at a cost of just $5 per kg. It requires just 10% of the energy used to create new carbon fiber.
Virgin carbon fiber can cost anywhere from $55 to $1980 per kg to produce, based on the quality of the finished product. It’s easy to see why recycled carbon fiber recovered using a fluidized bed process is so attractive. It can be had at a fraction of the cost with very little loss of stiffness. The only downside is that the recovered material is not as strong as its virgin counterpart.
Making Good Use of Waste
Assuming the University of Nottingham project leads to a robust carbon fiber recycling industry, what would it mean to the composites industry? First and foremost, it would mean making good use of what otherwise goes to landfills. If you are not clear on the impact of effective recycling, consider that the vast majority of high-end carbon fiber is consumed by the aerospace industry.
According to Materials Today, upwards of 8,000 aircraft will reach end of life by 2030. All the carbon fiber in those planes will either be scrapped or recycled. If it is scrapped, that means tons of carbon fiber waste heading to landfills or sitting out in the desert taking up space and collecting dust. Recycle it and you have a whole new ballgame.
Whether designers are fabricating pieces of an airplane wing or a panel for a car door, a certain amount of waste is produced. That waste could also be recycled using the same fluidized bed process.
It appears as though the British researchers are on to something. Now let’s hope what they proved in the lab can be translated into real-world recycling. If so, having a comparatively cheap way to reclaim carbon fiber waste will have a significant influence on the future of one of the most promising composite materials of our time.
Simon Hopes is a renowned author and social media enthusiast. Waste is also part of the fabricating process, according to Rock West Composites.
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