Hand-held metal analyzers are changing the operations of many scrap metal recyclers. With a growing number of choices in the market, choosing the right metal analyzer for your needs is the key to obtaining best results. For most recyclers, that means knowing and understanding customers' needs first.

Hand-held analyzers identify different materials in a sample the same way larger instruments do - by analyzing light energy unique to each element. When groups of elements are identified in a sample, the analyzer compares the sample data to possible matches in a library of possibilities. The library is a database stored in the unit. Each possibility corresponds to a known material-type.

For recyclers, the portability of hand-helds has simplified the sorting and identification of metals considerably. Stuart Freilich, of Universal Metal Corporation, Worcester, Massachusetts said, "It means we no longer saw off samples and send them to the lab. Now all of our testing is done right there on the spot."

There are essentially two types of hand-held metal analyzers used in scrap metal recycling today - optical emission (OE) and x-ray fluorescence (XRF). Each type has its advantages and limitations.

Optical-emission analyzers (OE) are commonly known as "arc/spark" devices. Essentially, OE analyzers send a charge of electrical energy to the sample that burns off a small portion of the material. This charge "excites" the atoms on the surface of the metal and causes moving electrons to emit light. The light is reflected back to the unit and analyzed to determine the presence of specific elements in the sample. OE analyzers have typically been used to identify a wide range of metals, and they are essential for identifying specialized alloys.

The second type of metal analyzer uses x-ray fluorescence, or (XRF) technology. Like OE-type analyzers, XRF analyzers work by "exciting" the atoms in a metal sample and analyzing light emitted by electrons in motion. With an XRF-type analyzer, metal samples are showered with x-rays from the instrument. The x-rays are returned to the unit to identify the material in the sample.

"Recyclers should consider the materials they primarily deal with," Tom Anderson, director of marketing for Niton, LLC, pointed out. "XRF is not well suited to analysis of aluminum alloys or mild steel, whereas these are the primary strengths of OE systems. OE systems are really the only good solution for someone dealing in these types of metals," he added.

Randy Moffat, vice president, sales & marketing of Angstrom, Inc., commented, "X-ray analyzers are good for most materials but won't analyze aluminum materials to the degree that most users require. Most arc/spark type analyzers can analyze the full range of metals, as long as C, P and S are not required." XRF analyzers are well suited to high temperature metals, nickel alloys, stainless steels and titanium.

There are differences in ease of operation as well. XRF systems are generally simpler to use, while some OE analyzers may require higher levels of knowledge, experience and technical ability of the operator.

Among XRF-type analyzers, there is still another consideration. The method of excitation - either by radioisotope, or through a newer, miniature x-ray tube technology. Each has implications for registration and licensing requirements.

Owner/operators of radioisotope-based XRF analyzers possess and use their devices under the provisions of either a specific or general Radioactive Materials License (RML). Tony Honnellio, Corporate Radiation Safety Officer for Niton, LLC pointed out, "Prior to taking possession of a radioisotope-based XRF analyzer, owner/operators should first determine whether or not they plan on using the instrument(s) in multiple states. If so, the owner should apply for a specific license with the Nuclear Regulatory Commission (NRC) or an agreement state. The specific RML would then be used to seek approval (reciprocity) to use an XRF analyzer in another state or NRC jurisdiction. Agreement states are those states that have signed an agreement with the NRC to regulate possession and use of byproduct radioactive material within their borders," he said. Regulation of byproduct material in non-agreement states is the responsibility of the NRC.

A list of agreement and non-agreement states can be found at: www.hsrd.ornl.gov/nrc/asframe.htm.

The NRC and some agreement states accept the provisions of a general license. A general license is issued to owners/operators through regulation (i.e. 10 CFR 31.5). It indicates that a device's design has a high level of safety associated with it. Possessing an XRF analyzer under a general license reduces the regulatory burden in that one does not have to apply for and maintain a specific RML. There are limitations however, especially if one plans on transporting the device from state to state (see above).

According to Mr. Honnellio, "Owners/operators of generally licensed devices are still required to conduct leak testing every six months, provide notification of loss, theft, or damage and assure that the radioactive material contained in the instrument is properly disposed of." Additionally, agreement states may require registration or have other specific requirements for generally licensed devices. "All generally licensed XRF analyzers containing more than one mCi of Americium-241 also require registration with the NRC or an agreement state," Honnellio added. More information on general licensing is provided in NUREG 1556, Volume 16, found at: www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1556/v16/index.html.

In turn, owner/operators of x-ray tube-based XRF analyzers are subject to minimum regulatory requirements as well. One of the main advantages of x-ray tube devices is the elimination of certain transportation requirements. However, these units must be registered with the state when purchased. Some states may charge a registration fee, require an expert to evaluate the device, or require operators to have specific training prior to use of the analyzer. Portable x-ray tube-based XRF analyzers that are used in more than one state are subject to the requirements of each state.

What are steel recyclers looking for in an analyzer today? For most, three priorities were often named.

First, a reasonably priced unit is important. John Hunsaker of SOS Metals, Gardena, California notes, "Prices on hand-held units have come down dramatically in the past three years, but these things still aren't cheap." Scrap metal recyclers can expect to pay roughly between $20,000 and $35,000 for a hand-held OE or XRF analyzer. Larger analyzers - such as those for laboratory use - can cost as much as $50,000 or more, depending on options or custom programming.

Next, scrap metal recyclers cited ease of use. While specialized operator training is available, most recyclers prefer analyzers be as simple to use as possible. "People have a lot to do these days," said Mr. Freilich. "Most recycling operations just don't have experienced metallurgists on staff," he added.
The third priority was reliability, or "reproducibility" in the case of hand-held analyzers. If recyclers depend on an instrument to guarantee material certifications, an inaccurate analysis could prove costly.

When choosing a hand-held analyzer, scrap metal recyclers should consider the training, support and post-sale service offered by each manufacturer. Mark Lessard, business development manager, Oxford Instruments, Inc., Concord, Massachusetts, pointed out, "Service policies should include a guaranteed turnaround on repairs in a reasonable period of time. Loaner units while repairs are being made should also be available." In addition, a good supply of replacement parts will help reduce any downtime in the event repairs may be needed.