NOVEMBER/DECEMBER 2006
Visual inspection can only go so far in identifying tramp metals in ferrous scrap. Using chemical analysis, the new CrossBelt Recycled Metal Analyzer can tell scrap processors and consumers the exact composition of what’s coming out of the shredder.
BY THEODORE FISCHER
Copper—which is used in items from pennies to pipes to pots and pans—is one of the few metals that most people can identify by sight. And by sight is how most scrap processors still identify copper when estimating its prevalence in a load of shredded steel scrap. For flat-rolled steel mills, however, that’s not always good enough. Copper is the bane of their existence.
“It’s a tramp metal in the steel that [mills] have no way of getting out” once it gets in the furnace, explains Alan Crouch, president of River Metals Recycling LLC (Fort Mitchell, Ky.). “If the copper level gets too high, it causes impurities and potential cracking in the metal. It creates seams. So copper is the big issue” for such mills, he says. “There are issues with some other elements, but nothing like copper.”
A few scrapyards have begun using a new tool to more accurately identify such contaminants in steel scrap. By analyzing the chemical composition of the scrap as it comes out of a shredder, the CrossBelt® Recycled Metal Analyzer (CB-RM) lets scrap companies tell steel mills exactly how much—or how little—copper is in the scrap they’re getting, which should make that scrap more valuable to the mills.
“The scrap industry and steel industry have for years dealt with the subjectivity of quality control,” says Daniel Pflaum, president of Gamma-Tech LLC (Cincinnati), the exclusive metals and recycling industry reseller of the CB-RM, which is manufactured by Thermo Gamma-Metrics, a division of Thermo Electron Corp. (Franklin, Mass.). “It’s visual inspection—my eyes versus your eyes in terms of what quality of scrap is acceptable to a steelmaker.” With the CB-RM, he says, “we give scrap processors the technology to talk about metallurgy, which truly is a value to their consumer base.”
For more than 20 years, the coal and cement industries have been using the technology that the CB-RM now applies to scrap: prompt gamma neutron activation analysis, which can identify the composition of nonhomogeneous materials. “It’s a fairly well-developed and mature, science-based [process that uses] nuclear technology to analyze materials,” Pflaum says. “I discovered it back when I worked for The David J. Joseph Co., and we adapted it and commercialized it to fit the needs of scrap processors.” River Metals Recycling, a DJJ company, bought the first Gamma-Tech CB-RM in late 2001.
Tunnel Vision
The CB-RM looks like an MRI machine designed for Paul Bunyan. It’s a 61/2-ton cylinder measuring 6 feet high, 6 feet wide, and 7 feet long, with a conveyor belt running through the middle. As shredded scrap passes through the cylinder, a radioactive isotope (Californium-252) at the bottom of the analyzer produces neutrons that penetrate the scrap and put the material’s atoms into an “excited state.” To bring themselves back to stable condition, the atoms emit gamma rays in distributions unique to each element. The analyzer examines the spectra from that reaction and identifies the signature energy levels of the elements of concern to steel mills, which might include copper, nickel, chrome, manganese, and zinc. Essentially, the analyzer confirms the chemical composition of the shredded material. With this knowledge, processors can make other adjustments to reach the desired scrap composition.
“We’re a speedometer on the back of the shredder,” Pflaum says. “We’re simply telling [processors] the chemistry of what they’re producing. We don’t change it, we don’t sort it, we just tell them how well they’re doing the job of removing the copper from what they’re producing.”
Pflaum says the CB-RM serves the particular needs of the scrap industry in three main ways: it handles bulk materials; it performs the analysis in real time; and it provides a full-surface analysis. “It fits the nature of what the ferrous side of this business has needed,” he adds. “Most of our customers—we have nine installations on shredders now—are using [it] to control the chemistry and provide their customers—steel mills—with a known analysis and, in many cases, higher quality product than they would have been able to supply without that information.” Processors market the shredded ferrous products that have gone through the analyzer under the name Gamma-Shred®.
System Specifics
Cross-belt analyzers are standalone installations that fit in line with a shredder behind its stacking conveyor. A typical installation will have a surge feed hopper that accumulates scrap coming off the stacking conveyor from the shredder. The hopper also can be fed by mobile cranes, overhead cranes, or front-end loaders. Behind the feed hopper is a shaker table that distributes material onto the variable-speed conveyor belt that passes through the analyzer.
The analyzer can work with just about any shredder speed; “it doesn’t matter to us,” Pflaum says. “We’re on everything from a megashredder with a 10,000-hp machine to much smaller units. But we need some control over the flow rate of what is going through.” Control systems meter the variable output of the shredder and maintain a flow into the analyzer in the range of 250 tons to 300 tons an hour.
The scrap does not require special preparation for analysis—it doesn’t need to be reduced to a single layer or spaced a certain distance apart. “On a 6-foot conveyor belt, we’re reading all the way through material that’s anywhere from 8 to 12 inches thick,” Pflaum says. “The reaction occurs at the speed of light and completely in the confines of the analyzer, so there’s no residual activity as [the material] exits the analyzer.”
Gamma-Tech handles all maintenance and service on CB-RMs. “It’s not a massive investment,” Pflaum says. “There are no moving parts on the analyzer other than the computer. But we take care of all the calibration, all of the support.” Customers do have to provide a technician to monitor the chemistry of the material being produced and to report the results back to the shredder, Pflaum says, but workers with basic computer skills can handle the job. “We’ve got all the nuclear physicists and metallurgists on our staff,” he says. “We provide the instrument, [the customers] provide the technician to help run it, and we provide all the technical services and support behind it.” Customers also can store results of the CB-RM analysis and print them out later.
So far only medium- to large-sized shredding operations have installed the technology. Pflaum says he realizes the product is valuable only to scrapyards with a specific kind of customer base, one that “will recognize the value of knowing the chemistry of what they produce,” particularly those “who are supplying flat-rolled steel mills that are sensitive to the chemistry of the scrap they’re using as raw material.” Scrapyards that supply rebar mills or mills that produce beams or plates don’t really need the CB-RM’s information.
How much does it cost? Pflaum estimates that for medium-sized shredding operations, it would add $1 to $2 per ton to the cost of processing the material, depending on the shredder’s tonnage output.
Customers and Caveats
River Metals Recycling is Gamma-Tech’s first and best customer. “We developed the product together, we were the test facility, and our Newport [Ky.] facility was the first one ever in production,” says RMR’s Crouch. The company currently operates Gamma-Tech analyzers in Newport, Louisville, and Henderson, Ky. The David J. Joseph Co. also has an analyzer at its Trademark Metals Recycling facility in Cocoa Beach, Fla., and plans to install units at Western Metals Recycling (Salt Lake City) and Texas Port Recycling (Houston).
The CB-RM “allows us to make a known-chemistry scrap product,” Crouch says. “It reads the main element—and the main element most steel mills are interested in is copper.” RMR’s flat-rolled steel mill customers, such as Gallatin Steel, Steel Dynamics, and Nucor, are willing to pay a premium for Gamma-Shred because “it’s an offset against busheling or No. 1 bundles or factory bundles, which are $40, $50 [per ton] higher now than shredded scrap,” Crouch says. “They’re able to use the material as a substitute for prime.”
Gamma-Shred is not a one-to-one substitute, he allows, because prime “supposedly has a copper level of anywhere from 0.06 to 0.1 [percent], and we can’t get the product down to that level because of the inherent copper in the material that we’re shredding.” But RMR can tell a company the average chemistry of the scrap over a set number of tons. “We typically do bargeload quantities—1,300 tons—and when we send a barge out we send along the certification that says the copper level is an average of 0.14 [percent] for the entire 1,300 tons.”
Crouch cautions potential buyers that the Gamma-Tech CB-RM is not some kind of Rumpelstiltskin device for spinning scrap into gold—or in this case, low-copper steel. “The machine will only tell [processors] what they are producing; it will not produce the material. You have do that in the yard, and that takes time and effort”—and money, he says. To get the best results, “you have to keep the density up in the material over what you might find in normal shredded scrap,” he explains. “Grinding to a higher density liberates the free copper so that you can get it out of the material. So it comes with a price in operating, and that’s why there’s a premium.”
Installing the CB-RM “is not a profit bonanza,” Crouch says. Instead, it’s “an incremental revenue stream for your business, and as long as the revenue stream is 30 percent higher than your costs, you’re in good shape.” In other words, “We make a nice profit off of that business,” he says, “but it’s a double, not a home run.”
Other customers appreciate the technology for both its current and its potential benefits. “This is not only a good economic investment but also an important cultural shift for our industry,” Daniel Dienst, chairman, president, and CEO of Metal Management Inc. (Chicago), said in a quarterly earnings conference call in February, after his company installed Gamma-Tech CB-RMs in its Chicago and Memphis yards. “We commend the metal shops around the country that have recognized the premium value of this product… .”
Last January, PSC Metals Inc. (Cleveland) installed a Gamma-Tech analyzer in its Nashville, Tenn., facility, and it has purchased an additional unit for its Chattanooga, Tenn., plant. “It’s probably the first step in a technology that’s going to become more and more important in the scrap industry,” says Ben Blemker, PSC’s CEO. “Now it’s predominantly [used for] copper, but as the technology improves we’ll be able to analyze more and more different types of metals, and we will be able to use it much more effectively in, say, aluminum and other industries that need to have that chemistry predictable.”
In fact, Gamma-Tech is in the process of adding further nonferrous analysis capabilities to the CB-RM. “We are ready to release the calibration that will allow us to do aluminum metals,” Pflaum says. “Shredders will have the option to run their nonferrous stream through the same analyzer. They’ll just have to flip over the calibration.”
RMR’s Louisville operation will participate in the development of the aluminum analyzer pilot project in 2007. “The whole idea is that sheet mills, whether steel or aluminum, want the highest quality—quality being scrap that’s got the lowest [percentage of] residual items in it,” Crouch says. “We feel like we can give them chemistry that they can use in their melt that they [will be able to] buy cheaper than the prime but at a premium over what we would do with the rest. We would build our own premium.”
A new way of thinking
Wide adoption of the Gamma-Tech CB-RM will require that both the scrap and the steel industries adopt a new mindset, Pflaum says. Scrap processors must be committed to controlling and certifying the metallurgical composition of the scrap they produce. “At the end of the day,” he says, “the idea is to use science and technology to describe the product based on its chemical composition, not its physical description. It’s not cut scrap, it’s not turnings, it’s not shredded scrap, it is a product that has a certain metallurgical value.”
At the same time, scrap consumers must understand the value of knowing the chemistry of what they buy and be willing to pay for that knowledge. “There are times when the scrap processors have been more innovative and creative, and consumers have been slow to recognize and adopt the technology,” he says.
The process of educating both industries has not always “gone as quickly as I would have hoped, but we’re making progress,” Pflaum says. “About a million-plus tons of this stuff is moving up and down the domestic market yearly. So we’re making headway, slowly but surely.”
Alternative Analyzers
The CrossBelt Recycled Metal Analyzer is not the first or the only kind of metallurgical analysis equipment on the market.
Arc-spark spectrometers analyze the contents of samples removed from steel mill or foundry furnaces. Benchtop or standalone units produced by several manufacturers (Angstrom, Spectro, Thermo Electron Corp., and others) shoot the metal samples with beams of electricity that cause electrons to move. They then “read” the energy produced by the reaction and analyze its contents. But arc-spark spectrometers can analyze only samples of homogeneous material. They cannot effectively analyze the nonhomogeneous material that emerges from a shredder.
The QXR-M Metal Scrap Sorter/Separator manufactured by Austin AI (Austin, Texas) combines an X-ray fluorescence spectrometer with an integrated charge-coupled device camera pointed at scrap samples passing it on a conveyor belt. The QXR-M can sort metals from nonmetals and simultaneously sort and separate alloys according to general classification: steel, zinc, copper, brass, bronze, and so on. The analyzer claims an average throughput of only 6 tons an hour for most applications, however, whereas the Gamma-Tech CB-RM reportedly handles 250 to 300 tons an hour.
Arc-spark and XRF technology also drive the handheld metal analyzers that use light energy to help scrap processors identify the composition of samples. Optical-emission analyzers are arc-spark devices that emit electrical charges that, when reflected back to the unit, can identify various metals, particularly alloys. XRF handhelds—which are manufactured by Angstrom, Oxford Instruments, Spectro, Thermo Electron Corp., and others—spray metal samples with X-rays that bounce back to the unit for identification.
Theodore Fischer is a writer based in Silver Spring, Md.
Visual inspection can only go so far in identifying tramp metals in ferrous scrap. Using chemical analysis, the new CrossBelt Recycled Metal Analyzer can tell scrap processors and consumers the exact composition of what’s coming out of the shredder.