Meatballs go well with spaghetti or smothered
with tomato sauce on a long Italian roll. They don't digest
well in a steel mill's electric furnace, at least those served
up with portions of shredded scrap.
The "meatballs" are copper armatures or parts
of copper motors from automotive starters and alternators or
the compressor motors in appliances. They are part of the
shredded flow because most have a magnetic steel rod.
"The meatballs are still with the shredded
because they have a steel shaft in the middle of the copper
windings," explained Bobby Triesch, vice president of ferrous
operations at Newell Recycling of Atlanta Inc. "Because that
steel shaft is there, it jumps over to the magnet."
When a junked vehicle or appliance is
shredded, the shredder's magnet picks up that steel shaft and
with it comes the copper that some steel mills dread because it
can harden their steel products, particularly flat-rolled
sheet. That can make it difficult to form into parts like car
hoods and doors. To counter that, most shredders have a picking
line as the last pass before the shredded is dumped into a pile
to be shipped to steel mills or loaded onto a boat for
Picking lines are manned by workers whose
task is to spot the reddish color of the copper meatballs-hence
the nickname-and remove them from the conveyor belt.
Copper wiring doesn't normally make it that
far through the shredding process, unless it is bolted to a
piece of steel or iron as a grounding wire. It normally drops
into the nonmagnetic fluff, or shredder residue. Inshredders
with additional downstream separation systems, it often is
recovered and sold as nonferrous scrap under such ISRI
specifications as Zorba or Zebra. Not to be outdone, the
copper-laden meatballs, or shredder pickings, have their own
ISRI spec Shelmo.
To reassure steelmakers that they are serving
up shredded that is as close to meatball-less as possible, some
scrap processors have purchased and installed the Crossbelt
Metal Analyzer from Cincinnati-based Gamma Tech LLC. And some
flat-rolled mini-mills that want lower copper content in their
shredded scrap-as low as 0.2 percent or less-are willing to pay
a premium for the so-called Gamma shred.
The Crossbelt Metal Analyzer uses prompt
gamma neutron activation analysis technology to identify
unwanted metals. It can provide a real-time analysis detailing
percentages of metals in the shredded material as it moves
along the conveyor, according to metallurgist Daniel Pflaum,
president of Gamma Tech. The device's aperture is 20 inches by
70 inches, allowing it to scan the width of the shredder's
Pflaum said the device does not just spot the
obvious chunks of copper, like meatballs-it also analyzes each
piece of metal that flows past and determines its copper
content as an alloy of the metal.
"We are actually bombarding the scrap with
highly penetrating neutrons and looking not only at the free
copper content but also the core copper content and the alloy
copper content in the base metal," he said.
So the Gamma Tech analyzer can size up pieces
of rebar that have been shredded as well as car parts. But the
Gamma Tech device doesn't pull the meatballs off the belt.
Instead, it enables the shredder operator to adjust the mix of
feedstock by, say, using more sheet scrap that contains less
copper or any of the other variables in the shredder operations
that can alter its output.
Thus far, said Pflaum, there are 13 Gamma
Tech analyzers operating at shredders in the United States and
two in Europe. River Metals Recycling in Newport, Ky., was one
of the first yards to use the Gamma Tech system. Others, like
Metal Management Inc., have added them to shredding operations
in Chicago and elsewhere.
Much of the pressure to reduce the copper
comes from the flat-rolled steel mills. "The solution is in the
dilution," said Pflaum. The mills can dilute the melt mix with
higher-quality scrap or other materials that contain less
All of the flat-rolled mills have different
specifications, he said, but all are below 0.2 percent on
copper, with some simply wanting it as low as possible.
Pflaum argues that it does not make much
sense for steelmakers to be so obsessed with the 0.20-percent
specification for copper in shredded. Instead, he said, they
can use shredded with 0.22-, 0.23- or 0.24-percent copper and,
knowing that it is there, design the furnace charge specific to
The steel world has become comfortable buying
scrap based on its physical description, he explained, and
implying from that some sort of metallurgical properties. Now,
however, it can know the actual metallurgical properties of the
scrap because a system like Gamma Tech's analyzer will give it
to them, he said. "What it allows the steel industry to do is
dial that grade of scrap up and down to fit the specific needs
of the mill without paying for scrap based on its physical
In the past month, Fort Wayne, Ind.-based
OmniSource Corp. and Innov-X Systems Inc., Woburn, Mass., have
agreed to work to develop an X-ray fluorescence system that
will both identify the copper and automatically remove it from
the conveyor belt.
The first automated copper extraction system
will be built for the shredder at OmniSource's home office yard
in Fort Wayne, Ind. It is expected to be up and running within
two to three months, according to Rick Comtois, president of
Austin Automation & Instrumentation, an Austin, Texas,
company that works with Innov-X to design such systems.
X-ray fluorescence technology will identify
scrap based on the metal's chemistry. But the system at
OmniSource is expected to go a step further by removing free
and commingled copper, eliminating the need for hand pickers on
Innov-X said that its system will be designed
to maximize cost-effectiveness, reducing the copper content in
shredded scrap, typically to less than 0.17 percent,
diminishing manual picking and obtaining higher-value
Pflaum said OmniSource has asked his company
to supply a Gamma Tech analyzer that will be installed beyond
the Innov-X system to determine the copper composition of the
shredded after it has passed through the automated removal
Innov-X and OmniSource are not alone in their
plans to pluck meatballs from the shredded stream. Wendt Corp.,
the Tonawanda, N.Y.-based shredder and eddy current equipment
supplier, has its eyes on those copper-steel clumps as
William D. Close, a Wendt sales engineer,
said the company's German partner, CommoDaS GmbH, will have a
production-scale sorting machine available in the second half
of 2008 that will use both X-ray fluorescence as well as
optical sensors to identify the meatballs and remove them from
the shredded stream.
Close said that CommoDaS is involved in the
mining industry and has systems that separate large
boulders-white rock from black rock-before crushing operations,
so it already has experience separating large, heavy objects.
Its shredded sorter will be an air separation system, but will
be different from anything that has been seen in the metals
industry. "We're using elevation drop," he said. "If you
visualize an asteroid in space, it does not take much of a
nudge to move the trajectory. It's kind of what they are doing,
but in a drop configuration. We're not lifting; we're just kind
of giving a little help (to move it off the conveyor)."
If the CommoDaS shredded sorter is anything
like its mining equipment, it will pack quite a punch. "The air
valves on it are so large that it is like a miniature shotgun
blast going off," Close said.