Profit center

Editor’s Note: This is the second of a two-part series focusing on auto shredder downstream metal recovery and sorting practices. The first story in this series, focusing on trends in ferrous recovery, appeared in the December 2013 issue of Recycling Today magazine.
 

Nonferrous downstream systems are getting smarter and smarter these days for a variety of reasons. Not surprisingly, one of those reasons is improved profitability.

“The nonferrous side of every shredder operation is significantly more profitable than the steel side,” said Bill Close, sales manager of Wendt Corp., Buffalo, N.Y., speaking to a room full of attendees at the Institute of Scrap Recycling Industries Inc. (ISRI) Operations Forum, held in October 2013 in Long Beach, Calif.

As to why this is the case, he added: “Your operating costs are lower, your revenue streams are significantly higher and it’s ever-changing.”

Close made these remarks at a presentation covering downstream nonferrous separation operations at the event.

Bearing out Close’s comments, conversations with executives from various system integrators serving the recycling industry confirm that downstream nonferrous sorting practices are in fact changing and have become more advanced. Nowadays, the goal of such systems and the recyclers who install them is to produce a wider array of upgraded product streams that have a higher value among scrap consumers.
 

Contributing factors

What’s driving this evolution, integrators say, at least in part, has been China’s Operation Green Fence policy enacted in 2013. The initiative, which is designed to reduce imported shipments of hazardous materials and garbage, has required shredder operators to take a closer look at just what’s in the zorba and mixed metals streams they are sending for export.

Experts across the industry say the mixed metals products sold to China, the zurik grade, for example, must have between 90 percent and 98 percent metal content to pass Green Fence regulations.

Another factor for some shredder operators is the realization that their fluff piles might be holding value in the form of lost metals. And, if that’s not troublesome enough, achieving higher purity and recovery levels aren’t the only issues today’s nonferrous operators are facing.

As Heiner Guschall, CEO of SICON, based in Germany, says, today’s shreddables also contain increasing amounts of electronics. Because of this, he explains, nonferrous metals as a component of auto shredder residue (ASR) are increasing from year to year.

“So, it’s very important that your downstream separation plant or new nonferrous downstream is achieving the maximum of efficiency in relation to the recovery of the nonferrous metals,” Guschall says.

Addressing all of these concerns is the goal of today’s newest approaches.
 

Leveling up

The timely point about recovering more—and more valuable—nonferrous metals was illustrated in a comment made by Scott Newell, president of The Shredder Co., Canutillo, Texas, who attended Close’s nonferrous presentation at the ISRI event.

“Not all nonferrous is created equal,” said Newell, raising the point that certain more valuable nonferrous metals—for instance, copper— also might be what’s ending up in the fluff pile if operators haven’t taken a good look at what they’re missing and how to get it.

Toward that end, Close and other executives from system integration companies say processors have several opportunities to improve their yields and product quality. By combining today’s latest technologies with some basic information, operators should be able to learn if they’re missing valuable opportunities.

First and foremost Close said, operators need to understand that different types of metallics tend to reside in different fraction sizes. He said equipment companies usually can help their customers by testing portions of their nonferrous stream and analyzing the results.

Close also said it’s the larger fractions of material—those measuring 1.5 inches or more—where most of the stainless steel resides. Meanwhile, the majority of die-cast aluminum is in the fraction sized 0.75 inches and smaller.

“It has nothing to do with the equipment,” Close said. “It has everything to do with the physical properties of the metal when it gets shredded within your process.”

It’s because of these tendencies, Close added, that proper sizing of shredded material is critical. That’s a belief shared by several other system integrators as well.

Scott McGlothlin, vice president of process solutions for Metso Recycling North America, based in San Antonio, says screening inefficiency is a common problem among many operations that can lead to lost metals. It’s common, McGlothlin says, for operators to run too large a range of particle sizes in the same stream. “This can lead to metal loss,” he says. “It is also a good practice to keep bigger pieces of material out of the primary process lines, dealing with them in a different manner, either reshredding or picking,” he says.

The variations in size cause problems on most of the equipment, he explains, especially larger pieces of the shred. “They don’t flow well on vibratory equipment and also create clusters of material that are difficult to deal with.”

Skip Anthony, vice president of sales and service for American Pulverizer Co., based in St. Louis, says while most of today’s systems are achieving good recovery percentages, they could probably be doing even better. “There’s still a lot of commingled metals that [operators] have to deal with,” he says. “I think that’s one of the biggest problems that people are dealing with today: What do they do to get the rest of those commingled materials separated?”

One of the key issues American Pulverizer is working on is helping midsized operators to achieve the same product qualities as those running much higher tonnages. This can happen, Anthony says, if systems are built for flexibility. “I think the biggest thing is flexibility of the line, so if we need to rerun materials, we can, easily,” he adds.

Other critical factors are the proper metering of the line and having a good, consistent flow.

Anthony adds, “I think that the more homogenous that material is size-wise, the better all the equipment is going to work.”

Toward that end, Close said in his presentation that a minimum of three cuts in the material stream tends to reduce burden depth, which is a key way to maximize efficiency of each separation step.

A related issue, system integrators say, is having consistently metered material. Anthony says material needs to be fed at a consistent rate and in a homogenous fashion on conveyor belts for the best efficiency at each piece of separation equipment.

“What you’ve got to do is split that material into three or more sizes and run it to separate machines,” he says.

Anthony acknowledges that even those operators who can’t afford three machines should be able to set up their systems with enough flexibility to accomplish the same goal. It can be done, he explains, by screening the material and having the machines configured to refeed material to one or two machines at different times if necessary. The operator may then be able to consider adding more equipment later on, Anthony adds, “as he starts to recover some of his investment in his initial system.”

Another key for helping to improve product recovery and quality, integrators say, is the technique of removing light material from the stream after eddy current separation and before it hits downstream sensor sorters. This, Close noted, can be accomplished with some sort of air machine or all-metal separator.

“The thing that we’re now focusing on is the impact of light fraction removal,” he said. This can be done by adding a small air system to the nonferrous plant, Close added.

“When you talk about how to improve the quality and you go back to your Green Fence challenges, you have the opportunity to pull the light fraction out using air.” Close said adding this step can remove as much as one-third of the ASR before the material gets to sensor sorting machines.

Chris Melenick, systems project manager with U.S. Shredder and Castings Group, headquartered in Trussville, Ala., agrees. He says adding this step enhances the quality of the nonferrous product. “You’re reducing the tonnage to the sensors, and you’re making a cleaner product by doing it,” he says.
 

Unmixed metals

Upgrading metals from the zurik stream is another new trend that system integrators and technology companies are helping operators to consider.

McGlothlin says the latest approach is for operators to consider their sensor sorters as part of a large process rather than as just one machine.

“Now people are looking at these plants as a complete system where each step of the process is critical to obtain the product qualities and recoveries you’re looking for.”

To do that, McGlothlin says, sensor sorting systems might be set up with a couple of specific sensor sorters aimed at breaking up the zurik stream into individual components.

“There’s more interest in techniques to efficiently break up this mixture of metals so you can increase the value of the package,” he says.

One way Metso is helping to do that is by configuring its sensor sorting system plants to sort materials based on various particle properties, including conductivity, size, shape and color. Shape-based sorts can be trained on long, stringy particles to recover insulated copper wire, while color sorts might look for red metals, he says. Plants also can be set up to look for two things at the same time, he says, like circuit boards and red metals. Furthermore, negative sorts could be employed to remove nonmetals from a product stream.

“By combining all these things,” he says, “you have a lot of flexibility in the kind of sorting you can do.”

Another company with a similar goal in sight is SICON. Here, Guschall is also helping operators to upgrade specific metals, and he’s isolating plastics.

“Our overall approach is total metal recovery from the shredder residue,” says Guschall. “Our aim is not to produce a product which needs to be reprocessed again but to produce a product which can be supplied to final customers.”

SICON’s approach begins with size reduction, then it uses sifting to homogenize the stream to one size before removing the fluff but not the plastics. The plastics and nonferrous metals remain together in one “heavy” fraction, Guschall says, and are processed together.

“We concentrate the metals in the heavy fraction,” he says. This fraction goes through a series of three sensor sorters to remove specific metal products before being granulated and then sent through a density separation step.

At the end, Guschall says, operators are left with a few grades of aluminum, a few grades of copper and stainless steel. There is also a plastics stream, some of which could be recycled or recovered for energy value. “We do not have any more mixed metal fraction at the end of the process,” he says.

Guschall says what’s unique about this approach is that it allows an operator to generate a marketable nonmetallic fraction during the same process, making the investment payback period rather short at between two and four years.

“A large portion of it can be used for recycling, as in plastics to plastics, or it can be supplied to compounding plants,” he says of the recovered plastics.
 

Doing the homework

How can shredder operators know if their business might benefit from some sort of upgrade to the nonferrous plant? The key is doing a bit of research.

Operators should have a clear understanding of their recoveries and of what’s in the ASR stream, Melenick says. “You have to explore the options,” he says. “Then do the cost exercise to see what type of return on investment you’re going to gain by putting in the investment.”

Close offered a similar view. He said that knowing what is being lost in relation to what was shredded is critical.

To this end, Close said plant operators need to take the time to figure out their typical recovery percentages, with the help of their equipment suppliers if necessary. In today’s marketplace, the importance of this information can’t be underestimated.

“Numbers never lie,” he said. “They don’t tell you the whole story, but they never lie.”

The author is an editor with Recycling Today and can be reached at lmckenna@gie.net.