Anyone who’s worked with wind turbine blades or just seen one up close can attest to the massive size of these clean-energy workhorses. Ever thought about what happens to that costly, high-tech material once the blade reaches the end of its lifespan in 20 years or so?
Increasingly, at least in the case of newer blades made of carbon fiber reinforced polymer (CFRP), the reinforcing material is retrieved and recycled. The same goes for the carbon fiber (CF) in airliners that have reached the end of their service life and for leftover material from the aerospace industry, which has a commonly estimated scrap rate of about 30 percent.
“A staggering 62,000 metric tons (68,000 tons) of unused end-of-life and CFRP production waste will be accumulating every year in spite of the existing demand for new fiber composite,” wrote lead author Sankar Karuppannan Gopalraj in February 2020 in a review of the industry in SN Applied Sciences. “The aircraft and wind energy sectors contribute to a major share of this.”
Partly as a result, the global recycled carbon fiber market size is expected to grow from $109 million in 2020 to $193 million by 2025, at a CAGR of 12 percent during the forecast period, according to research firm MarketsandMarkets.
A growing mountain of recyclable material, the desire to monetize it and divert it from landfills, along with the high cost of virgin carbon fiber and the drive to lightweight vehicles from cars to rockets all contribute to the growth of the recycled carbon fiber market. Reclaimed carbon fiber is about half the price of prime and can be just as good as virgin material, said Andrew Maxey, CEO of carbon fiber recycler Vartega, Golden, Colo.
As in other young industries, Maxey and his fellow CF recyclers are working on material availability, the supply chain, quality and cost. The pandemic has thwarted some of their progress. For Vartega, that meant putting a plan to deploy its technology at the recyclable material’s source on hold. For now, all recycling is done at its plant.
Vartega uses a chemical process developed by Maxey. The process is applied to uncured thermoset prepreg, a term for pre-impregnated carbon fibers where a matrix material is already present. After separating out the CF, the fiber can be milled, chopped, pelletized or used in non-woven fabrics and made into filament for 3D printing.
In one use, the company can chop up the CF and add it in various fractions to different thermoplastics, including polypropylene (PP) and polyamide (PA) for injection molding. The resulting carbon-reinforced PP and PA are “incredibly important” for auto manufacturing, Maxey said.
“It’s really all about dropping into their existing supply chain,” said Maxey. “They’re already making millions upon millions of fiberglass-reinforced, injection-molded parts. Why not offer higher performance with carbon fiber?”
Pound for pound, fiberglass used to make bodies, engine covers, air intake manifolds, and other vehicle parts is cheaper than even recycled carbon fiber, but manufacturers can use less CF to achieve the same mechanical properties.
“The other benefit is weight reduction,” Maxey said. “Because we can use less material overall, you get either a part that’s the same weight with higher performance or even lighter weight. So, there are different ways to get close or in some cases get cost parity with a better part design.”
Maxey is working with the Institute for Advanced Composites Manufacturing Innovation, Ford Motor Co. and others to get Vartega’s recycled material into the auto industry supply chain. Maxey knows he has a high hurdle since the industry is slow to adopt new materials.
But that hasn’t stopped the CF recycler. Vartega has already diversified, and its recycled CF is used in consumer products, sporting goods, musical instruments and electronics.