Squeezing Out Value

Just as people try to squeeze that last little bit of toothpaste out of the tube, save the last drop of milk or collect their pennies in a jar, scrap processors are trying to get every last drop of value out of their materials. They view selling or disposing of auto shredder fluff without advanced downstream processing as throwing away money.

As margins get tighter, volumes decline and competition grows, one way auto shredding operations have made up the difference is by extracting more value from the material that enters their facilities. In the past, auto shedders would have eddy current separators to sort out nonferrous metals after the shredding process, but now more elaborate downstream systems are much more prevalent.

Just ask Chris Melenick of U.S. Shredder and Castings Group, Trussville, Ala. He says that while U.S. Shredder continues to sell auto shredders, there is more interest among processors in upgrading their nonferrous processing lines at existing shredding plants. He thinks this trend will continue. “It seems like everybody has some interest in doing an upgrade,” he says. “From the small guy to the big processor, everybody is trying to squeeze the last bit out of their fluff.”

Seeing Results
Melenick says a large percentage of auto shredding operations have some sort of downstream system that may include one or two eddy current separators to make zorba. In that scenario, the remaining insulated wire or stainless steel in the fluff goes either to a secondary processor or to a landfill.

Three nonferrous fractions are produced with downstream equipment from U.S. Shredder and Castings Group.

“Now what guys are realizing is that if they put more sizing in and break [the material] out into three different fractions, they can increase their recovery by 20 percent,” Melenick says.

A typical nonferrous processing system begins with sizing equipment. Without sizing, Melenick says, “you cannot make a quality product.”

In typical setups, a trommel makes three cuts: 1.5 inch-minus; 1.5 inch to 5 inch; and 5 inch and overs. The overs are hand picked or reshredded. The 1.5-inch-minus fraction passes over a screener with five-eighths-inch holes, producing the five-eighths-inch-minus fraction.

Wendt Corp., Tonawanda, N.Y., uses a similar configuration in the downstream systems it installs. Wendt Sales Manager Bill Close suggests following a few basic principles in a nonferrous system: “Feed it, screen it, mag it and separate it.”

He says a well-laid-out plant includes a batch feeder that delivers a uniform, consistent flow, screening that produces three sizes of materials plus overs and a magnetic prep step that removes ferrous solids and ferritic dirt. With this preliminary processing, Close says eddy current separators and sensor-based sorting can be highly efficient as the next step.

“Downstream plants can now be laid out very efficiently with a few machines that are both cost-effective and versatile,” says Close. “Fines processes have evolved with these same core machines and processes, and a surprising amount of value is available for recovery. Small, bare copper and precious metals reside in these streams and offer significant opportunities.” He does not recommend screening out what he refers to as the “bottom cut.”

Close says Wendt is introducing systems that are equipped with air classification to remove the light materials fraction. The air classifiers are operating at the Wendt Test Center and will be incorporated into several systems the company is building this summer, he adds. “This is making cleaner products and a cleaner work environment for people,” Close says.

Sorting With Care
Shredding and nonferrous separation involve very different approaches in Close’s estimation. Where shredding is all about tons on the ground at the end of the day, he says nonferrous plants need an operator willing to watch the process and to make changes as necessary. “If you are running an extra-rich batch of materials, you need to recognize the opportunity and slow the plant down to maximize the revenue,” Close says.

Plant performance should be monitored at all times, he advises. When recoveries are dropping off, then it is time to perform maintenance. If nozzles get plugged, Close advises operators to clean them before they continue processing.

Close says the proper performance of magnetic-inductive separation is tied directly to a uniform, thin flow of properly sized materials. “If materials span too wide a size, significant amounts of cast aluminum will not be recovered in the zorba fraction, thereby putting pressure on sensor machines to perform following them and resulting in misplacements into other recovered streams,” he says.

Melenick has similar advice, saying, “The sensor is great technology, but if you are not sizing properly, it can be a nightmare.” For instance, he says, if five-eighths-inch minus material is getting into the five-eighths-to-1.5-inch material, it will create a dirty product because the sensor will hit smaller pieces of copper and ferritic dirt.

Air classifiers are running at the Wendt Test Center and are being incorporated into several systems being installed this summer.

Not a Lot of Fluff
Most auto shredder fluff contains between 12 and 15 percent nonferrous metals, according to Melenick, so it is easy to see how further processing can equal added value. What may not immediately be apparent is how quickly a downstream upgrade can pay off.

Both Melenick and Close agree that a typical ROI for downstream systems is two years or less. Melenick admits that it may take a little longer for smaller processor to receive payback on a system. However, companies that are investing in downstream technologies have more control over their products and higher recovery rates, both of which can give them a competitive advantage.

Melenick admits many auto shredders still have old nonferrous processing systems, but he says that will change. “I think the more educated people become, the downstream systems are going to evolve,” he says.

Melenick predicts the next development in auto shredder downstream processes will be with plastics, saying there is enough volume to support systems development in this area.

What is certain is that scrap processors are looking for ways to divert more material and to make more products, and installing or upgrading a nonferrous separation system downstream of an auto shredder can make those goals attainable.

Close concludes, “Operators must find new ways to be competitive, and nonferrous systems that are simple and well designed can deliver on this.”

The author is a managing editor for the Recycling Today Media Group and can be reached at ksmith@gie.net.