Digging through fluff to separate plastics is no easy recycling task

Nov 22, 2006 | 09:07 AM | Michael Marley

About 10 million autos are shredded in the United States each year. Steel is recovered magnetically and, with the higher prices paid for copper and aluminum, eddy current separation systems have become significant profit generators for many shredder operators.

That still leaves the remaining nonmetallic portion, called automobile shredder residue (ASR) or fluff. Much of it is hauled to landfills, where is becomes the cover layer for each day's amalgam of municipal waste.

But there's still plenty of recyclable material that could be reclaimed. Argonne National Laboratory, which has been sifting through some of the estimated 3 million to 5 million tons of ASR produced annually, said there is more than 1 million tons of polyurethane foam and more than 750,000 tons of thermoplastics in those hills outside the nation's shredders. And it's likely to grow even richer as more and more plastics are used to lighten the vehicle's weight and provide better fuel economy

The problem is that it's difficult to separate shredder fluff into component parts. Some methods separate materials according to their density, but some plastics are similar in density and cannot be separated to a high enough purity. Other methods require large quantities of organic solvents, which raise environmental concerns.....