Prep work: carefully sorting and then pre-chopping wire can help processors create a high-quality product - Cover Story

Recycling Today, Oct, 2001 by Brian Taylor

Coaxing attractive, high-quality nonferrous grades from scrap wire and cable has become an important segment of the metals industry.

If the quality of metal obtainable from scrap wire and cable ever was a secret, that secret is out, and the scramble for material may be more competitive than ever.

Established and entry-level processors of wire and cable are now competing not only for material, but also to design the process that will yield the purest grades of copper and aluminum.

THE FRONT OF THE LINE

Several dozen scrap processors in the U.S. have had wire chopping lines in place for a number of years. The wire choppers continue to compete with smaller processors, who strip the wire and cable with lower-capacity equipment, and with export brokers looking for copper and aluminum to send overseas.

Wire choppers need a steady volume of material for operations to pay off, but for the quality of the outbound material to stay high, the right equipment has to be in place.

Increasingly, pre-chopping machines that cut wire and cable down to smaller pieces (and begin the separation process of plastic coating from the metal within) have gained favor.

French equipment maker MTB has been successful in placing its shredding machines with several U.S. wire choppers to use as a first step in wire and cable processing. The MTB units are sturdy enough to handle large volumes of wire or cable while saving wear and tear on the granulators that will eventually process the same material.

"MTB has done, in my opinion, an excellent job in designing and creating a pre-shredder that can handle all kinds of scrap," says Marty Rifkin, president of the Nonferrous Specialty Group of OmniSource Corp., Fort Wayne, Ind.

"It's almost like a primary granulator," Rifkin says of the MTB machine used at his company's Fort Wayne wire chopping operation. "You put grates in the bottom of it to size your material, getting pieces from four inches to one inch in size. The old shredders and shears would give you two-feet pieces, and inconsistent pieces at that. Now we've got very uniform feedstock. It has really helped throughput."

Seeing MTB's success, other companies are now offering new or modified machines to act as pre-choppers. Wendt Corp., Tonawanda, N.Y., represents the Eldan line of equipment from Denmark. "The Eldan Heavy Pre-Granulator is a medium speed machine that runs at 120 rpm," notes Tom Wendt Jr., import division sales manager of Wendt Corp. The company also makes a Super Chopper.

According to Wendt, the machines can handle cable up to three or four inches in diameter, with the hydraulically-driven Super Chopper being especially geared for thick cable. "It's a low-speed high torque machine at 22 rpm that can be used for the really heavy material. It's reversible [and thus not subject to jams] and makes a six-inch piece for further size reduction."

Other units made by Eldan and other companies are designed to pre-process baled or bundled cable.

Mallin Bros. Co. Inc., Kansas City, Mo., uses a shredder made by American Pulverizer Co., St. Louis, as an initial processor of some of the wire and cable it takes in. "Our pre-shredder has been in place about four years," says president Jeffrey Mallin.

"It increases our production and throughput," he says of the American Pulverizer machine, and he praises its "beefiness" and durability.

While a pre-shredder can help chopping lines handle thicker cables, most processors are still selective about which types of wire and cable they will put through their high-production chopping lines.

So called jelly-filled cable with its gooey insulation is turned away by processors if they do not have the specialized equipment to deal with it. "We don't take jelly-filled cable," says Mallin. "We used to do it years ago with an oil absorbing system, but it created havoc and is cost prohibitive."

Coaxial cable is also considered a separate animal by many processors. "We've never gotten into it," notes Mallin. "There is not a lot of metal, and the Styrofoam filling is gummy and sticky."

Even at lower volumes, the material can be difficult to process, says Bob Alexander, president of Strip Technology, Fort Worth, Texas. His company makes wire stripping equipment, but it is not effective for coaxial, he says, "because of the steel couplings that seem to be there every three or four feet."

Like Mallin, Alexander also cites the reduced amount of metal to be recovered as a strike against coaxial processing. "It just seems like there's not much copper in there, and there's no profitable way to handle it. You can rack your brains all day and get four or five pounds of copper."

SCHEDULED DETOURS

With markets for chopped copper and aluminum wire firmly established, smaller processors as well as scrap generators are increasingly trying to profit from the material before it gets to the major chopping operations.

Wire stripping machines have long been available to smaller operators as a way to separate metal from plastic and create a marketable material. Alexander says he sells his Strip-Tec device to "a wide variety of customers, including demolition companies, scrap yards and electrical contractors."