Recycling plastics in automotive components extends the value stream, but at what cost?

The devil is in the material-sorting details

Lightweighting has been at the forefront of automotive design for nearly a decade, especially since the mandated Corporate Average Fuel Economy (CAFE) standards reached 54.5 mpg, something that many automotive R&D engineers say will be nearly impossible. However, as they say, “plastic makes it possible.” And not only possible but recyclable, as well.

Automotive recyclingA Market Watch report just released by SPI: The Plastics Industry Trade Association (Washington, DC) underscores the need for more suppliers to reduce the weight of vehicle components, and that means transitioning from metal to plastics, including carbon-fiber-reinforced plastics (CFRPs) that provide both lighter weight and strength. According to IHS Automotive (Southfield, MI), a research firm that examines critical areas that impact businesses around the world, by 2020 the average car will incorporate an estimated 770 pounds of plastic by weight compared with 440 pounds in 2014, an increase of 75%.

Metal-to-plastic conversions are happening throughout the vehicle from interior and exterior parts to under-the-hood components and fuel systems, as automotive OEMs look for any ounce of weight savings they can squeeze out. And that means more opportunities for polymer technologies. “Already the third largest sector of U.S. manufacturing in dollar value of shipments, plastics in the automotive industry will continue to grow as new materials are utilized in design. CFRP usage in vehicle will increase from 3,400 tons in 2013 to 9,800 tons in 2030,” said the SPI report, Automotive Recycling: Devalued Is Now Revalued, noting that this will also mean new recycling opportunities.

These plastic materials and parts can be recycled, notes the SPI report, “either at the manufacturing facility as part of a post-industrial recycling program that many automobile companies and parts manufacturers have adopted,” and the recovery option that will eventually extend to end-of-life vehicles. “Closed-loop recycling . . . adopted by manufacturers is recognition of the value of the plastics and byproducts in their manufacturing and the opportunity to recycle plastic parts into new components,” the report states.

Obviously, recycling the plastic from vehicles is good news, but participation is key. Sorting the materials will be a factor in the success of automotive recycling. That might mean dismantling vehicles piece by piece to ensure that various types of plastics don’t comingle to maintain the value of the plastic materials. However, the SPI report notes that “end-of-life vehicle (ELV) recycling of these plastics can come via specific parts--the plastic used in bumpers—or in the auto shredder residue (ASR) that is ultimately produced in the crushing and shredding of ELVs. Reusing these plastics from the ASR requires sorting and cleaning, but companies in the European Union are recycling plastics from ASR.”

Currently, there are 39 different types of polymers used to make an automobile today; three polymers account for one-third of the plastics used: Polypropylene (32%); polyurethane (17%) and PVC (16%). There must be a better way to capture these materials that create the most value as recyclate. Yet, the SPI report points out that the cost of cutting-edge “technologies required in a state-of-the-art recycling facility runs into the millions of dollars.”

That leads me to ask just how much this adds to the cost of manufacturing when figuring in the ELV costs of a vehicle, as more and more of the vehicle converts to thermoplastics. The addition of CFRPs and thermosetting materials in the mix presents new problems, as thermoset materials can’t be recycled (although advances are being made on that front—keep an eye out for some news in that regard). The SPI report makes note of these problems: “. . . expanded use of carbon fiber does present challenges when it comes to recycling post-industrial recycled scrap and ELVs.”

The first step in the recycling process is dismantling the vehicle. The next two steps are the crushing, and shredding of the crushed vehicle. If the plastics can be recovered from a vehicle post-shredding, I’m curious how they prevent comingling of the various types of plastics, which can be a problem when creating reusable plastic materials. It is a process that would seem to be a manual job, with care taken to ensure there is no comingling of plastic types. I understand that magnets can be used to separate metal from plastic, but sorting the types of plastics from a pile of shredded materials might be a different story. Currently, in the United States, says the SPI report, the remaining materials post-crushing and shredding (plastics, rubber, wood and paper) “are processed into fine ASR that is sent to landfills.” Five million tons of this ASR is sent to landfills each year in the United States, “with automotive plastics representing 0.5% by weight of a typical landfill.”

In Europe, states the report, “due to mandates on recycling and use of recycled content, more ASR is separated using float/sink tanks, dryers and other technology to separate plastics and other fine ASR materials, diverting material from landfills.”

The separation process is tedious because of the “wide variety of plastics used in automobiles” which, as the report notes, “is a challenge for recyclers.” To separate metals from plastics in the ASR, methods such as “float tanks” are used, which employ water to segregate non-ferrous and ferrous metals and plastics from the ASR. Also used is the “eddy current” process, as well as laser and infrared sorting. The float separation process is used in a number of types of plastics separation, particularly separating plastics from the paper that may be stuck to the recyclate. That means hundreds of gallons of water, in some cases very hot water, and even chemicals are used to help the process.

That presents yet another problem, which often occurs in the case of so-called solutions, and that is the global problem of availability of clean, potable water and using the global water supply in the best possible way.

Additionally, if the goal of lightweighting automobiles is to be more environmentally friendly through higher miles-per-gallon of fossil fuels, thus reducing CO2 emissions, how much CO2 is produced in the recycling process? That would have to include the energy to operate equipment for shredding and sorting, or even the resources that go into manual sorting, given the energy used by employees getting to and from work.  Ultimately what is the real value of the plastic shred if it is comingled material? Isn’t the value of the recycled plastic based on the quality of that recyclate? Certainly the total cost-to- manufacture has to include end-of-life costs, which must add a considerable amount to the overall costs.

With the percentage of plastics in ASR increasing in the coming years, it behooves the market to come up with more environmentally friendly ways to use that ASR. The cost to separate, sort and create good, usable regrind material suitable to be molded into new parts is a big stumbling block for the industry. As the SPI report notes: “While all of the thermoplastic polymers are technically capable of being recycled, it can cost more to separate, clean and collect each polymer than to purchase virgin plastic—particularly with the recent low oil and natural gas prices.”

The cost of being perceived as “green” or “sustainable” will continue to be considerable, but the value of plastic materials can be realized in recycling. But exactly what type of recycling will be most beneficial and cost effective? And the big question: Will consumers be willing to pay for the costs associated with ELVs?

Comments (0)

Please log in or to post comments.
  • Oldest First
  • Newest First
Loading Comments...