MATEC recovers metals from ASR with the help of SSI shredders

Worldwide, approximately 50 million vehicles leave the roads each year, most of which are recycled, which involves shredding the vehicles to liberate and separate the materials.

Once the large pieces of metal and plastic have been removed, shredder operators are left with debris that is either too small or irregularly shaped to capture. This residual byproduct is known as automotive shredder residue, or ASR.

ASR, which can account for as much as 15 percent of the weight of each recycled vehicle, is comprised of a variety of materials that typically are categorized into two groups: a coarse fraction and a fine fraction. The coarse faction is a mixture of rubber, foam, plastics and fibers, while the fine fraction consists of metals, glass, residual plastics and dust. The metal content regularly accounts for 25 percent to 30 percent of the ASR’s total weight and is rich in copper and aluminum.

ASR’s small size and variable nature make it challenging to recycle, and it historically has been relegated to landfills. Special equipment is needed to properly liberate, separate and recover the copper and aluminum from ASR. The remaining "fluff" can be turned into refuse-derived fuel (RDF). This multifocused approach diverts all ASR from the landfill, and it is precisely what Japanese recycler and materials company MATEC is doing.

“All shredder dust goes to a controlled landfill,” says Kousuke Mitsu, executive officer and branch manager at MATEC in Hokkaido, Japan. “But, since we built this facility, we are stopping [ASR] from going to the landfill. Instead, we recycle it as material.”

MATEC is Japan’s largest end-of-life vehicle recycler and encounters a significant amount of ASR. To address this, the company built a new system to process the ASR generated from its six auto-shredding facilities.

Turning ASR from a waste product into a resource depended on MATEC’s ability to shred and grind large volumes of ASR while maintaining a small, uniform and well-liberated particle size. MATEC opted to incorporate shredders from SSI Shredding Systems Inc., Wilsonville, Oregon, into its system.

“When it comes to recycling, we will do whatever it takes to resolve troubles. That is our style,” Mitsu says.

To maximize results, MATEC preshreds its ASR using an SSI M100SD two-shaft shredder before feeding it through two of SSI’s high-capacity rotary grinders, the SR900 Uni-Shear. While preshredding is not required to process ASR, it does greatly improve the efficiency and thruput rate of the rotary grinders, SSI says.

“I believe that SSI's unique approach of combining shredding technologies allows us to build shredders that are tough enough to process these materials while maintaining efficient processing,” says Rich Ellis, sales manager of SSI’s Asia Market Department.

After grinding and liberating, the next step is sorting. Material is first passed under a magnetic separator to remove ferrous metals, followed by eddy current and sensor-based separators to extract and sort nonferrous metals like copper, aluminum and stainless steel. The remaining material then processed through screening and density separation equipment to remove the residual fine fraction and optimize the quality of the cleaned fluff. The fluff is now ready to be used as fuel.

The remaining fine fraction can be passed through the system multiple times for maximum metals recovery.

MATEC’s motivation to create value from its ASR stems from the Japanese principle of mottainai, a phrase literally translated as, “Don’t be wasteful.” However, the concept of mottainai is much deeper than that as it represents the appreciation and recognition of the intrinsic value of things. When applied to ASR, MATEC’s mottainai perspective drives the company to extract the maximum value from the shredder dust and keep it from being thrown away.

MATEC wants to take its mission a step further by exhuming and processing the ASR that has already been landfilled.