NOVEMBER/DECEMBER 2007
Even with new technologies that give an exact readout of metal composition, experts still see the value in teaching workers how to identify metals in traditional ways.
BY KIM FERNANDEZ
Some of what arrives in a scrap metal yard is easy to recognize. Most people can tell a car from a soda can, after all. White goods, window frames, pipes, wire, and radiators are all easy to identify by sight. But that’s just the tip of the scrap iceberg. Industrial scrap might arrive as punchings, turnings, or sheets. Scrap might arrive painted, dirty, rusty, or otherwise disguised in its appearance. So when a yard receives a truckload of unidentified scrap, a new worker might wonder, how in the world will I know what it is and what to pay for it?
With the proper training, tools, and lots of experience, just about anyone can master the art of metals identification. It’s a crucial skill in a scrapyard. After all, you can’t purchase scrap for the right price—let alone sort, process, and sell it—if you don’t know what it is. That might mean either a basic assessment or a very specific analysis of the scrap’s chemical composition. Advances in metal analyzer technology can help: Today’s portable, hand-held devices can provide readings in just a few seconds. But many longtime scrapyard operators insist that such tools can never fully replace the tried-and-true identification techniques that have existed for decades.
Using Your Senses
Jim Lawrence, a trader with ELG Metals (Houston), has been identifying metals for more than 30 years. He remembers learning how to recognize materials using very little equipment, relying mainly on his eyes and his memory.
“We did it by knowing what certain symbols were on the metals, [with] magnets and grinders, and we learned the business through application,” he says. “I believe firmly that that still needs to be taught in our industry.”
Jeff Arrow, vice president of purchasing at TIMCO (Fontana, Calif.), offers metals ID training to his customers and their employees, starting with the basics. “The very first thing they should be doing, if they have a magnet, is put that magnet to the metal,” Arrow says. “If it’s not magnetic, there’s a good chance it’s aluminum or stainless steel.” Many professionals carry magnets around in their pockets to easily perform this test.
Next, he says, “we teach them to look at the color.” Unpainted metals that are reddish are copper; yellowish metals are brasses; and silver or gray nonmagnetic metals are likely stainless or aluminum. A trained eye usually can tell the difference between the two, Arrow says. “Stainless has a little more shine to it,” whereas “aluminum is a little duller.”
Handling the metal can provide clues as well, Arrow says. “We teach them to look at different physical characteristics.” First, consider weight: Stainless steel typically will be heavier than aluminum. Also check if the metal is pliable, Arrow says. In aluminum, some 1100-series and 3000-series metals are thin and bendable, and their higher aluminum content might make them more valuable than other, more rigid alloys.
On nonmagnetic materials, Arrow trains people to check for a mill mark: Some mills still stencil on a number that gives a good clue to the material’s makeup. Common mill markings in aluminum include 2024 and 7075, Arrow says. ELG Metals trains workers to memorize some of the most common markings. For example, Lawrence says, “when they look at a valve and it says CF8M, they have to know by memory that’s 316 stainless.”
Asking the seller about the material’s source is another option. “If it’s an industrial account, we teach people to ask what the metal was used for—sometimes that will tell you what the alloy is,” Arrow says. An aluminum extruder might only use 6063 series aluminum, for instance. “Once they’ve pinpointed the alloy, then they can figure out the best place to go with it.”
To move beyond appearance, markings, and magnetic properties, most yards are equipped with tools for basic chemical analysis of a metal sample. In spark testing, some types of metals—such as brasses and nickel alloys—give off sparks when held against a grinding wheel. The color, length, and pattern of the sparks can determine what type of metal it is. The more carbon in a piece of steel, for example, the more vivid the sparks. And steel alloys that contain tungsten will give off reddish sparks.
Similarly, in chemical testing, dropping a bit of acid or other specific substance on a metal sample produces a chemical reaction or color change that differs based on the chemical composition of the metal being tested. Arrow gives his students a handout of the different colors a cadmium chloride test can produce on aluminum alloys. A drop of the liquid cadmium chloride is applied to the metal. If the alloy has a high zinc content, the liquid turns gray, he says. If the alloy has no zinc, the liquid stays clear. And if the alloy contains magnesium, the liquid will bubble and turn black.
High-Tech Methods
More modern technologies are quickly gaining ground in metals identification. The spectrometer, for example, aims a beam of light onto a piece of cleaned metal and quickly produces a readout of its chemical makeup. Spectrometers now come in large, stand-alone machines and small, hand-held devices that look a bit like ray guns from science-fiction movies.
Spectrometers are “very reliable,” says Jim Hurlburt, an account executive with Global Recycling (Charlotte, N.C.). But they’re also expensive: He estimates they cost between $10,000 and $50,000, depending on features and speed. An X-ray fluorescence machine performs a similar type of analysis, but it’s even more expensive than the spectrometer and not yet used as widely. Still, Hurlburt says, “a lot of scrapyards have invested the necessary capital and means to bring their identification into modern times” with these tools. “There’s not a lot of old-time identifying going now. We’re relying more on analytical equipment to know exactly what we have.”
But don’t retire the grinder just yet, some say. As these tools proliferate, differences between readings can become an issue. Say that “supplier A checks some material and finds it’s 50 percent nickel,” Lawrence explains. “We check it and find it runs at 48 percent. So there you get into a difference, and that difference translates into too much paid and a loss in sales.”
Often the problem is in how someone has prepared the tested material, he says. Many new users don’t know the importance of cleaning materials before they test them. “If you don’t properly prepare the surface before you test, you can easily get a false reading.” Lawrence encourages his clients to bring their own machines to his plant for proper training. Equipment calibration is essential as well. TIMCO calibrates its spectrometers daily, Arrow says.
Despite the specific, detailed knowledge of chemical composition an analyzer can provide, not every yard has one or chooses to invest in one. “Any old-timer in the business will tell you they never use those hand-helds,” Lawrence says. For one, he says, the old ways can be faster. “If you’re standing in front of 100,000 pounds” of material with a spectrometer, “how many pieces can you really check in an hour?” he asks. “You can get a pretty good idea of the pile’s analysis and identify the alloys through that analysis. But when I’m looking at a pile of 100,000 pounds of stainless steel, and I can see hubcaps and beer kegs and sinks, I don’t need a hand-held [analyzer] to know that the hubcap is approximately 6.5-percent nickel, the sink is roughly 7-percent nickel, or that the beer kegs are approximately 8.4-percent nickel.”
Training for success
One factor all these testing methods have in common, from magnet to spark to chemical to XRF, is that training is essential to ensure they produce the proper results. Learning the different methods for identifying metals is a necessary process, Lawrence says, but he admits it’s not an easy one. “It takes a minimum of two years, and that’s for the basics,” he says. “Certainly, I see it as a lifetime process. I’m still learning.”
Metals identification is part of ELG’s two-year employee training program. All new workers “actually operate the instruments that we use to identify metals,” Lawrence says. That’s the key to having an efficient, accurate scrap business that can quickly sort, process, and ship materials that are exactly what they claim to be, he says.
“We’ve got to train our sorters, who are going through the metals, but the person going through [the training] could also be a forklift operator or a crane operator,” he explains. “That forklift or crane operator should still know the basics about the metals if [he or she is] taking materials from one area to another, especially with the values of alloys today. It would be a critical mistake to take a nickel alloy and dump it into a lower-grade pile. It could cost us thousands and thousands of dollars. Knowledge and communication are two extremely important assets to every scrap operation.”
As Hurlburt puts it, “if you’re going to sell these materials to consumers, you have to know exactly what you’re identifying. … If you’re going to use acid or a magnet or spark testing, you have to have a lot more training,” he says. “You have to develop a really keen eye for sparks, the reaction to the acids, and things like that.” These methods are largely as accurate now as they were years ago, provided the people doing the identification have been properly trained, he adds. “And if you’re training on more modern equipment, you have to know how to clean the surface, spark it with the equipment, and read the machine correctly.”
Good for Business
New equipment and a commitment to training in both scrapyards and consuming facilities have increased the accuracy of metals identification, so mistakes (genuine or otherwise) are becoming much more rare. That, industry experts say, has increased profitability on all ends—and made it all the more annoying when someone tries to pull a fast one.
Most scrapyards are more than happy to use their specialized equipment to identify materials if their suppliers can’t, Arrow says. “There are always going to be some items that people can’t identify,” he says. “When that happens, we encourage people to send us a sample. We’ll evaluate it for them. That way, they’re not sending us something that has no value to us.”
Hurlburt says the practice is more common when the scrapyard believes a metal it’s buying is among the more valuable alloys. “If sellers think they may have something a little more special or
a little more valuable, and they don’t have the proper analyzing equipment, they can send it to the buyer, who will analyze it for them and tell them exactly what it is,” he says. “That helps out
a lot. If a guy calls and says he has 20,000 pounds of something valuable, he can send a sample out and find out for sure.”
In the end, the value of testing your scrap is discovering what you’ve got, which enables you to determine the material’s value and find the best market for it. “When you know what you have,” Arrow says, “you can get the highest return on it.” That should spark every recycler’s interest.
Kim Fernandez is a writer based in Bethesda, Md.