Metal Analysers

The need to accurately buy and sort scrap has never been greater. Fortunately, today’s electronic metal analyzers can offer scientific help.

By Robert L. Reid

Robert L. Reid is managing editor of Scrap.

Though the scrap industry is full of legendary metal sorters who can identify different alloys just by sight or touch, the rest of us can always use a little help. Sometimes, that help comes in the form of magnets, acid, or grinding wheels for visual spark analysis—all relatively low-tech or no-tech approaches. And just as with those legendary sorters, the results are highly subjective, based on the user’s experience and interpretation.
   Today, with scrap markets as tight as they’ve ever been and customer requirements as demanding as anyone can recall, many processors will be glad to know that there’s a more scientific way of identifying and sorting metal: metal analyzers, also known as spectrometers.
   These devices—which range in size from handheld units to benchtop models and even laboratory-size equipment—are state-of-the-art versions of a technology that’s been analyzing metals since roughly the turn of the previous century. 
   The first commercial use of a “spectrograph” occurred approximately in the year 1900 for analyzing nonferrous metal, though it probably wasn’t until the 1950s that a spectrometer was used to sort scrap metal in the United States, notes Randy Moffat, vice president, sales and marketing, for Angstrom Inc. (Belleville, Mich.), which manufactures and distributes 
spectrometers.
   The science behind metal analyzers centers on the fact that all chemical elements—including the various metals that scrap processors collect—can be made to “uniquely emit energy which characterizes only that element,” explains Moffat.
   This unique energy can involve either light or X-rays, depending on which of the two types of electronic analyzers is used: an optical-emission (OE) device that creates an arc or spark on the sample and then analyzes the light produced, or one using X-ray fluorescence (XRF) that bombards the sample with X-rays—usually from a radioisotope—and then analyzes the rays that are returned. Each type is used by the scrap industry, and each has its advantages and limitations (see “Exciting Analysis” on page 60).
   Like other metal-identifying methods, the earliest versions of spectrometers were far less technological and relied heavily on the user’s skill—such as the ability to manually interpret data and correct for interference, Moffat says. But today, the use of personal computers, semiconductors, and other advanced technology with or within spectrometers has made the devices far more powerful, accurate, and user-friendly.
   According to a recent case study written by Andrea Kinney of analyzer manufacturer NITON Corp. (Billerica, Mass.), one Massachusetts scrap recycler credits XRF devices with helping him increase his firm’s productivity in identifying and sorting metal by roughly 20 percent. Plus, his operators don’t have to jump through complicated technical hoops or do mathematical calculations by hand.
   To use the metal analyzers, the recycler told Kinney, “you simply ‘point and shoot’ the sample and get an answer in five seconds.”

Examining Analyzers
When trying to identify the type of metal analyzer that’s right for your needs, it’s important to remember that some manufacturers make both OE and XRF devices while others focus on just one of these technologies (each individual analyzer, of course, only uses one or the other system).
Of the seven firms currently manufacturing electronic metal analyzers for the scrap industry (see “Analyzer Options” on page 60), three offer just OE systems, two offer just XRF systems, and two offer both.
• Angstrom Inc.: This Belleville, Mich.-based company, founded in 1969, manufactures its own laboratory-size OE spectrometers and serves as the exclusive U.S. distributor for the benchtop and portable OE devices from Britain’s Arun Technology.
   Among Angstrom’s offerings, the Arun Metalscan 1650 is the most widely used by scrap processors, the company says. A suitcase-based system that weighs roughly 44 pounds, the 1650 identifies ferrous and nonferrous metals by grade and performs a semi-quantitative analysis. It works well with all metals, the firm notes, but especially aluminum. The system analyzes pressed samples (not raw turnings) using a handheld probe and a light-sensitive chip called a charge-coupled device (CCD).
   Angstrom also offers two other CCD-based Arun analyzers: the Metalscan 3000 portable unit, which weighs roughly 38 pounds and can be transported via shoulder strap, and the Metalscan 2500 benchtop spectrometer, a 44-pound unit that’s not designed to be carried. The 2500, which requires a moderate temperature-controlled environment, is “optimized” for ferrous metals, the company says, as well as low-carbon and stainless steels.
   Angstrom’s own product, the V-950 laboratory spectrometer, is a large unit weighing 750 pounds and that uses a photomultiplier tube rather than CCD chip to analyze metals under a “conditioned environment,” the company reports.
   Angstrom offers portable analyzers within a price range of $26,000 to $45,000. The benchtop model costs $30,000 to $80,000 while the laboratory versions cost $45,000 to $80,000.
• EDAX Inc.: Founded in 1962, EDAX (Mahwah, N.J.) produces one XRF analyzer for the scrap industry—the handheld CT 3000. Weighing just 6 pounds, the CT 3000 can perform, store, and analyze up to 10,000 assays in a three-shift operation, the company notes. An onboard library begins with nearly 300 standards for classifying and identifying grades of metal from aluminum alloys to zinc and zirconium. Plus, a user-defined library lets operators add additional unique or special standards. All data collected can then be saved and transferred to a personal computer.
   The CT 3000 works well with various shapes and sizes of metal, including screws, turnings, flats, plates, and powders as well as small and “odd-shaped” components, the company notes. 
   To operate, the user simply presses the analyzer against the metal sample or inside the bin of turnings and then depresses the trigger. Within seconds, the device provides a graphical representation of the sample, identifying the metal by grade and chemical characterization, EDAX says. A quantitative analysis is also available within minutes. The CT 3000 uses a cadmium-109 radiation source, though other sources are available based on application, the company notes.
   The CT 3000 costs from $28,000 to $60,000 depending on overall capabilities and radioactive source.
• Metorex Inc.: Created in 1994 and based in Ewing, N.J., Metorex is the U.S. subsidiary of a Finnish firm (previously known as Outokumpu Instruments) with more than 30 years of experience manufacturing both XRF and OE instruments used by the scrap industry.
   Metorex’s handheld XRF analyzers include the X-Met 2000 MetalMaster and X-Met 880. Weighing just 12.5 pounds, the X-Met 2000 features a rugged, ergonomic design that permits onsite analysis “even in the most demanding scrap yards ... and variable environmental conditions—from hot and wet to cold and dry,” the company states. With just a pull of the trigger, the battery-operated unit identifies ferrous and nonferrous alloys within two to five seconds, and provides a complete chemical assay after a reading of 10 to 60 seconds. Despite the radioactive source at the heart of the X-Met 2000, Metorex stresses that the device is safe enough to be transported as checked baggage on commercial passenger flights.
   The company also offers benchtop XRF units such as the X-Met 800 and X-Met 1000. In addition, it manufactures OE systems such as the Arc-Met 930, a portable arc spectrometer that comes with an optional mobile cart to help transport the unit and its argon cylinder (often required for OE processes) over longer distances.
   Metorex’s XRF analyzers range from $19,000 to $35,000 while OE systems cost $45,000 to $50,000 depending on configurations and calibrations.
• NITON Corp.: NITON (Billerica, Mass.), which has been manufacturing XRF devices since 1994, introduced a handheld XRF alloy analyzer in 1998 “at the specific request of a customer in the recycling industry,” the company notes.
   Products include the XL-800 and XL-II 800 series analyzers, which feature handheld devices weighing only 2.5 pounds and user-friendly operations—just “point, shoot, and read the result,” NITON says. A standard identification is available in three to five seconds, with the material’s chemistry analyzed within 10 to 20 seconds, the company notes. XL-II 800 models also include an ergonomic pistol grip and extended battery life. 
   Both series are well-suited for analyzing high-temperature alloys, particularly high-alloy steels, stainless steels, nickels, nickel/cobalts, titanium alloys, and many red metal alloys, says the firm.
   NITON offers no-cost radiation safety and instrument training to customers and provides a shielded waterproof carrying case for its handheld devices in case the shutter that exposes the instrument’s radioactive source malfunctions.
   NITON also offers a stationary floor-size alloy analysis system—the XRT-800 series—that employs X-ray tube technology, which eliminates the need for multiple radioisotopes to cover the full range of elements in metal alloys, the company says. X-ray tubes also reduce regulatory hassles, while allowing faster analysis times without the slowdown over time that is characteristic of radioisotope decay, the company explains.
   A typical NITON metal analyzing system for recyclers costs roughly $33,000.
• SPECTRO Analytical Instruments Inc.: This German firm, with U.S. operations headquartered in Fitchburg, Mass., started manufacturing metal analyzers about 20 years ago and has supplied OE instruments to the recycling industry for nearly all that time, the company notes.
   SPECTRO’s products include both stationary or laboratory devices as well as mobile units. The laboratory equipment includes the SpectroLab S, SpectroLab M&F, SpectroLab Jr. CCD, and SpectroCast, which generally must be used within a controlled work environment and require samples that have been cut to a predefined size and brought to the analyzer, SPECTRO explains.
   Among the company’s mobile devices, the SpectroSORTCCD is a battery-powered handheld OE unit that weighs roughly 2.2 pounds, making it ideal for sorting scrap metals at a demolition site, in a railcar, out in a yard, or at a scale prior to accepting the material, SPECTRO notes. The unit analyzes metals within four seconds, can store up to 1,000 analyses for later retrieval, and can provide information in multiple languages, including English, Spanish, German, French, Dutch, and others. Moreover, it does not need argon.
   The larger mobile unit—SpectroPORTCCD—weighs 33 pounds and includes an optional transport cart to help move the argon supply. It features multiple CCD detectors and can work in either a rapid pass/fail arc mode or a spark discharge that provides near laboratory accuracy, SPECTRO says.
   The SpectroSORTCCD starts at less than $20,000 while the modular Spectro-PORTCCD is priced below $25,000 for the basic unit, with available options as required.
• Thermo ARL: Based in Dearborn, Mich., Thermo ARL—like its sister company, Thermo MeasureTech (see below)—is part of Massachusetts-headquartered Thermo Electron Corp. The ARL business unit, formerly known as Applied Research Laboratories, started manufacturing analytical spectroscopy equipment in California in 1934.
   Today, its products—which incorporate equipment from the Baird, Hilger, and Scintag lines as well—include three OE instruments well-suited for the scrap industry, ARL notes. The benchtop Assure argon-flushed spectrometer features a CCD detector that allows for broad-spectrum coverage with maximum flexibility, which is especially useful when a variety of metal analyses are required, the company says. The Windows-based system also offers a touch-screen interface and the ability to perform quantitative analysis, material grade identification, and fast sorting.
   ARL’s floor-sized Metals Analyzer model is a powerful photomultiplier-tube (PMT) system configured for ferrous, copper, or aluminum. Its powerful analytical software operates in Windows 2000 using HTML/Internet technology and offering features such as password protection, user-definable analysis formats, and shortcuts for ease of operation, the company says.
   In addition, ARL offers the 3460 Metals Analyzer, which is custom-designed as a multichannel/base unit for the requirements of the scrap industry, minimills, foundries, forges, and similar operations.
Thermo ARL products range in price from $30,000 to $110,000.
• Thermo MeasureTech: Thermo MeasureTech (part of Thermo Electron Corp.), based near Austin, Texas, was formerly known as Texas Nuclear Technologies. The company introduced its first analyzers in the early 1970s and today manufactures and distributes both OE and XRF systems that incorporate Pentium computers, onboard floppy disk drives, bar code readers, and other advancements.
   The OE units feature a user-friendly touch-screen Windows display and either an arc or spark system, as indicated by the product names: Arc Pro, Spark Pro, and Spark Pro C. Though mostly used as benchtop analyzers, these OE models can be powered by batteries and taken into a scrap yard via a dolly, the company notes. OE systems work well with aluminum and carbon steels, as well as nickels, brasses, bronzes, and other metals.
   Though its XRF analyzers—which include the Scrap Pro and Metallurgist models—aren’t the lightest or the heaviest on the market, Thermo MeasureTech notes that a field pack allows these normally benchtop instruments to be taken out into a scrap yard, with a small and light probe for access into tight spaces. Its XRF units also feature extensive software flexibility in analyzing additional alloys, plus data storage, retrieval, and labeling functions, the company notes. Features such as a desktop option with a separate monitor were designed specifically from scrap industry input, according to the firm. The devices work with either single or dual radioisotope sources that only need to be replaced at four-year intervals, which Thermo MeasureTech says is the longest useful life in the industry.
   Thermo MeasureTech’s OE analyzers range from $24,000 to $40,000 while XRF units cost $26,000 to $40,000.

An Ever-Changing Technology
Over the past several decades, metal analyzers have grown increasingly smaller, more powerful, and more affordable thanks to technological advances ranging from microprocessors that eliminated the need to do certain calculations by hand to lighter batteries that hold their charge for longer periods of time, manufacturers note. Metal analysis has moved from the laboratory out into the field, where scrap dealers can now use the technology at their own site to quickly accept or reject shipments at the scale or decide while on the road whether or not to purchase a particular load.
   Remember that Massachusetts scrap dealer who was studied by NITON? He predicts that even smaller scrap firms are likely to find that metal analyzers have become a necessity of doing business. “Their customers are using this technology as well,” he explained, “and will no longer tolerate mixed or inaccurately sorted scrap.” •

Exciting Analysis
Both OE and XRF analyzers work by “exciting” the atoms in a metal sample.
   OE devices use an arc or spark from an electrode to burn off a small amount of the sample’s surface, thus causing the electrons to change from their normal pattern to an excited one. The resulting light emitted as the electrons return to their normal state is analyzed according to the unique color or wavelength associated with each element, and a computer then uses an internal alloy data library to identify the best match.
   XRF analyzers use a radioisotope—usually iron-55, cadmium-109, or americium-241—to shine X-ray energy (also called gamma rays) on the surface of the metal sample. The excited atoms then fluoresce energy back to a semiconductor detector, which compares this reflected energy to the specific energy levels associated with the various elements in its data library to identify the best match.
   Though XRF devices tend to be less expensive than OE analyzers, they’re also often considered less precise. For instance, XRF models have a limited ability to analyze certain aluminum and magnesium alloys. Plus, the inclusion of radioisotopes in most XRF devices requires users to meet certain state and federal licensing and radiation safety rules.
   In turn, OE analyzers are more labor-intensive. They require that the metal sample’s surface be free of dirt, oil, grease, grime, or coatings of any kind or the results could be inaccurate. Also, the OE arc or spark can heat up metal samples enough (especially aluminum alloys) that users might need to wear gloves to avoid burning their hands. Plus, OE analyzers can be less portable than XRF devices—sometimes even the “mobile” OE models require a cart to carry around the gas cylinder needed for the argon flushing stage common to many OE analyzers.

Analyzer Options
Here’s the basic contact information for the seven companies profiled in this article, all of which manufacture and/or distribute metal analyzers for the scrap industry:

Angstrom Inc., 800/395-5393 or 734/697-8058 
(fax, 734/697-3544), www.angstrom-inc.com

EDAX Inc., 201/529-4880 (fax, 201/529-3156)
www.edax.com

Metorex Inc., 800/229-9209 or 609/406-9000 
(fax, 609/530-9055), www.metorex.com

NITON Corp., 800/875-1578 or 978/670-7460 
(fax, 978/670-7430), www.niton.com

SPECTRO Analytical Instruments Inc., 800/548-5809 or 978/342-3400 
(fax, 978/342-8695), www.spectro-ai.com

Thermo ARL, 313/271-5770 (fax, 313/271-5542)
www.thermoarl.com

Thermo MeasureTech, 800/736-0801 or 512/388-9100 
(fax, 512/388-9222), www.thermomt.com