The combination of bigger, more powerful shredders and tougher specifications from steel mills has put new pressure on scrap processors to produce a cleaner, lower-residual shredded scrap.
Specifications from some flat-rolled mini-mills have become even more demanding, several shredder operators said. Melters are looking for shredded with lower residual elements overall, but are demanding a copper content of less than 0.18 percent, down from the 0.25-percent level once considered acceptable.
"They are looking for less tramp elements in any scrap today, and certainly shredded," said Rob Bakotich, vice president of sales and marketing at Detroit-based Ferrous Processing & Trading Co. (FPT), which operates several shredders in that region.
Also, more mills are using shredded these days, he said. That might not be the case in the current ferrous market, where the price of shredded is in parity with top prime steel scrap like No. 1 busheling. But a year ago, when prime industrial scrap prices skyrocketed, many mills substituted lower-cost shredded for No. 1 busheling and No. 1 bundles.
"Sales of shredded have gone up. That may not be true in the market today, but prior to that, when there was a substantial differential between prime scrap (like No. 1 busheling) and shredded, demand was strong," Bakotich said.
Even basic oxygen furnace (BOF) melt shops are using shredded, while electric-arc furnace shops that have a long history of using shredded are shifting their scrap mix and increasing the amount of shredded in the charge.
"They are using more shredded and (shredder operators) are trying to refine it further, picking it more because the mills want guarantees that the tramp elements are out," he said.
Many shredder operators have installed inspection machines and other devices to provide proof that their shredded meets mills' specifications. These machines don't remove the residuals. That has to be done beforehand with better preparation of the feedstock and separation equipment that captures more of the nonferrous metals.
"The separation equipment and technology in the market today is superior to what it was even seven to 10 years ago," said Scott Gibble, northern Indiana divisional manager at OmniSource Corp. in Fort Wayne, Ind.
That enables OmniSource to produce cleaner shredded for steel mills and foundries, but it also helps do a better job of separating non-metallics and reclaiming nonferrous metals, he said. That was a big bonus to many shredder operators last year, when prices for copper and other nonferrous scrap soared.
The technology for analyzing shredded has been available for a few years. With flat-rolled mills looking for low-copper shredded, the technology can confirm copper content. "That has forced people to do a better job of segregation in front and a better job of picking the free copper out of (the finished product)," Gibble said.
The combination of improved technology and better practices have made operators smarter about separating the materials that are fed into the shredder, he added.
FPT stresses that practice of cleaner feedstock to its suppliers—auto wreckers and junkyard operators—by paying a little more to those suppliers with a cleaner feedstock, Bakotich said. It also helps protect the machinery from damage.
"Unshreddables in a load are still probably the largest danger to shredders today. If someone is putting something that is not going to go through those grates—a hunk of steel or a die block—you have to be vigilant," he said. That means no batteries, no tires, no fluids and no mercury switches, he said, noting that the removal of these items should be the industry norm.
FPT also practices what it preaches about cleaner feedstock at its own auto junkyards, Bakotich said. That's not something new to the company, he said, adding that the big Motor City scrap processor has been doing that for years.
Most shredder operators have an inspection process upfront to make sure they aren't putting in materials that are environmental hazards, safety hazards and heavy scrap.
Michael Richmond, an OmniSource operations manager, said a key factor is training employees that are out in front of the machines what to look for. "Educating your people out front is very important," he said.
OmniSource has inspectors on the ground to identify both problem materials and those that are appropriate to put into the machine, Gibble said. Since shredders are larger and more powerful than in the past, operators are able to feed larger items into the shredder that used to be sheared or torched.
Another step to producing cleaner shredded is operating with more material in the shredder box, Gibble said. "There is a theory out there—and we subscribe to it—called full-box shredding. If you can keep the mill box full of materials when you are shredding, you end up with an abrasive action in the machine. It works against itself as well as working against the hard surface in the machine," thus producing smaller pieces and making it easier to separate the metals.