LIBS Vs XRF - NDT) Products

equipment focus: Handheld scrap analyzersLIBS vs XRFby Keith Barker, EditorFor recyclers who sort metals and alloys, inapplications where precise understanding ofcontent and composition is paramount, X-rayfluorescence (XRF) based handheld analyzershave been the main tool employed for over adecade. In recent years, however, laser-induced breakdown spectroscopy (LIBS) technology has been usedincreasingly in metal recycling applications, especiallywith aluminum and other nonferrous metals, and for lightelements. XRF is still considered by most to be the bestoption for applications in stainless steel and heavy metals,or for recyclers focused on plastics and e-waste sorting.To put it most simply, XRF technology uses X-ray radiation to determine metal and alloy content and composition, while LIBS uses low-energy lasers and optical technology, providing analysis without radiation concerns.Overall, advances in handheld analyzers for scrapmean recyclers can now identify and sort a wider range ofelements and alloys, including light elements, in the yardor in their facilities, with high speed, accuracy and safety.Both LIBS and XRF, now feature smart, reliable connectivity to data analysis tools, and are designed to be lightweight, rugged and ergonomically friendly for users.Recycling Product News asked some of the industry’sleading manufacturers to provide insight on how the twotechnologies compare.48 Recycling Product News March 2018Hitachi High-Technologies’ VulcanLIBS analyzer employs advanceddata management for logging ofboth results and images.Bruker: A tale of two technologiesBruker, a leading U.S.-based manufacturer of both XRF and LIBShandheld analyzers, describes XRF technology on their companywebsite as a completely non-destructive process whereby electronsare displaced from their atomic orbital positions, releasing a burstof energy that is characteristic of a specific element. This release ofenergy is then registered by a silicon detector in the XRF handheldinstrument, which in turn categorizes the energies by element.With LIBS technology, Bruker’s site describes the concept as follows. “With LIBS, a laser pulse strikes the surface of the sample andablates an amount of material and generates a plasma plume (partiallyionized gas). The energy of the laser is low, but is focused to a microscopic point on the sample to generate the plasma. In this plasma,emitted light is transmitted through optical fibres and the polychromatic radiation is dispersed in one or more spectrometers anddetected by CCD chips.” (CCD is an acronym for “charge coupleddevice”, an image sensor technology that converts light into electricalcharges, as used in most digital cameras.)In a 2015 white paper, by John I.H. Patterson, Phd., a consultantfor Bruker and expert on the topic of metals analysis, he comparesthe two technologies in detail. He writes: “For fast sorting of aluminum alloys based upon light elements, LIBS is clearly the bestalternative, as well as for separating many magnesium and titaniumgrades. When precision and accuracy matter more, as in PMI (positive material identification) analysis and quality control or when pricefigures are required in scrap trading (Ni, Mo, etc.), or if your application is measuring stainless steel, high-temp alloys or other heavymetal alloys, then XRF is the still the method of choice.”

TSI’s ChemLite LIBS analyzerprovides high accuracy andspeed for light metals.TSI: LIBS provides speed, ease ofuse and low cost of ownershipTodd Hardwick is the global marketing manager for TSI Incorporated, acompany focused on the manufacture ofLIBS handheld analyzers.“XRF cannot compete with LIBSwhen it comes to speed, ease of operation and cost of ownership,” says Hardwick. “Our ChemLite LIBS analyzersprecisely identify metals in one to twoseconds, much faster than with XRF.”Hardwick says that because thereare no radiation concerns and theirunits use an eye-safe Class 1M laser,ChemLite “gun” owners avoid regulatory hassles – such as radiation licensing and the paperwork that comeswith it.“LIBS requires no special trainingor storage and ChemLite LIBS gunsdo not need argon gas to operate,” hecontinues. “When you add up the extratime, fees, training and supplies thatXRF requires, the cost of ownership isoften lower for LIBS.”Hardwick adds that when it comes toaccuracy, LIBS is a clear improvementover XRF for light metals.“LIBS allows better, faster aluminumalloy separation,” he says. “Our ChemLite LIBS guns have limits of detectionas low as 1 ppm.”Overall, for Hardwick, LIBS isthe tool of choice for nonferrousrecycling yards and aluminum scrapsorting.“Our engineering teams at TSIChemLogix patented a LIBS sensor forin-line metals analysis a few years ago,”he says. “Our customers have deployedthese sensors successfully for high-volume automatic aluminum scrap sortingas well as part of a Zorba/Twitch sortingsystem.”Hardwick does add though that LIBSis not a viable option for plastics recycling or e-waste applications accordingto their experience, whereas XRF technology is a viable tool for use in theseapplications.March 2018 www.recyclingproductnews.com49

equipment focus: Handheld scrap analyzersOlympus’ Vanta handheldscrap analyzer on the job.Olympus: Each has its placeAccording to Ted Shields, portable products manager, analyticalinstruments division, Olympus Scientific Solutions Americas, LIBS is bestviewed as a complimentary technologyto more traditional handheld XRF, andeach type of technology does certainthings well.“The most intriguing thing aboutLIBS is the ability to measure elementsthat you cannot measure with XRF,”says Shields. “Carbon, beryllium andlithium are all possible, and recentadvances are making carbon in L-gradesachievable for some LIBS analyzers.”He says however that LIBS technology struggles with some elementsthat XRF excels at. Most notably, hesays, these include refractory metals, such as Cr, Zr, Mo, Ta and othercommon and commercially importantalloying elements.“LIBS has a much smaller spot sizethan XRF,” continues Shields. “This isgood in the sense that the burn mark leftbehind is small. But it makes it muchharder to get the same answer when youtest twice in a row. This is because thesample varies across the small scale ofthe LIBS spot.”He says some LIBS analyzer manufacturers compensate for this by recommending users take several shots at dif-50 Recycling Product News March 2018ferent places (called rastering the laser).But this adds to the test time.“Variations in sample geometryeffect the results to a much larger degree for LIBS,” he continues. “LIBSis also more sensitive to moisture andsurface contamination. Some manufacturers try to address this by recommending users perform a cleaningpre-burn with the laser, again addingtime to the analysis.”Shields continues by adding thatwhile LIBS calibrations are empirical,XRF metal calibrations are Fundamental Parameters (FP). “FP lets the XRFinstrument calculate the effect of everyelement on every other element,” hesays. “This calculation lets one XRFcalibration be remarkably accuratefor a wide range of samples. On theother hand, empirical calibrations areonly as broad as the samples used tocreate them. If you analyze somethingoutside of the range of calibrationsamples, the results can be dramatically wrong. This is why LIBS analyzersrequire users to choose among severalcalibrations, and why making the rightchoice is critical to achieving reasonable results.”Shields also emphasizes that knowledge about what materials are beingdealt with is critical to achieving higherpurity standards, especially in light ofincreased global standards for end materials, including those recently established by China.“One sample with a high concentration of an undesirable element cancontaminate an entire batch of metal,”he says. “The only way to know is totest. And the test needs to be quick andportable – like it is with handheld XRFtechnology,” which he adds “are fasterand more sensitive than ever before,making it possible for recyclers to meethigher purity ly destructiveYesCarbon analysisPossibleNoElements lighter than MgYesNoRefractory elementsPoorGoodSpot size50 to 100 micrometer diameter 3 or 9 mm diameterArgon ionEmpiricalFundamentalparametersTable courtesy of Olympus Scientific Solutions Americas.

Hitachi High-Technologies: speed vs range of applicationFor Hitachi High-Tech’s latest LIBS analyzer (the Vulcan)speed is the biggest asset to scrap metal recyclers as this maximizestheir operational efficiency during metal sorting. According toSean McKernan of Non-Destructive Testing (NDT) Products, anOntario-based distributor for Hitachi High-Technologies analyzers; “by employing point and shoot operation, Hitachi HighTech’s Vulcan LIBS technology, creates a simple, fast routine forrecyclers which eliminates user related errors and ensures consistency of results.“Our Vulcan is able to provide an accurate alloy ID, oftensufficient for most scrap metal recyclers,” says McKernan. “AndVulcan’s advanced data management allows logging both resultsand pictures to make reporting easy and complete.”He adds that as a laser analyzer, there are no requirements foroperator certification and licensing, which is required for XRFoperation in Canada.”Hitachi High-Tech’s latest XRF analyzer, the X-MET8000, istypically used in metal recycling and scrap yards when accurateon-site alloy identification and chemistry are required.“The optimized combination of a high performance X-raytube and large area silicon-drift detector (SDD) delivers theresults required in even the most demanding metals applications,” says McKernan. “The X-MET8000 is used for analysis oflight elements (Mg to S) and most commercial alloys, includingaluminum, titanium, bronze and high temperature alloys. The lowHitachi High-Technologies’ X-MET8000 XRF-basedanalyzer features calibration options that suit variousrecycling applications.limits of detection provide accurate grading and determination of impurities and penalty elements.”McKernan adds that unlike Hitachi-High Tech’s LIBSmodel (Vulcan), its X-MET8000 HH-XRF analyzer isavailable with calibration options that suit various recyclingapplications. The X-MET8000’s plastic FP calibration, forexample, is optimized for the determination of a wide rangeof elements (Cl, Cd, Hg, Pb and many others).“In instances where separation of chlorinated fromnon-chlorinated plastics is required, The X-MET8000March 2018 www.recyclingproductnews.com51

equipment focus: Handheld scrap analyzerscan be used to ensure that materials such as PVC are not incinerated,preventing damage to the incinerator’s masonry as well as the releaseof harmful dioxins into the atmosphere,” explains McKernan.“HHXRF is also often used ate-waste recycling facilities to quicklycheck for the presence of preciousmetals such as gold (Au), as well astoxic elements such as lead (Pb), todecide the next best processing step,”he says.“In automobile scrap yards, Hitachi High-Tech X-MET8000 withCar Catalyst calibration is used inthe determination of platinum, palladium and rhodium at various stagesin the recycling and refining processof automotive catalytic converters.“Empty exhaust converter cans,manifolds and pipes can also be sortedon-site using the X-MET’s alloycalibration,” he says, “adding furthervalue to the recycling process.” RPN52 Recycling Product News March 2018Bruker: S1 TITAN (XRF)The S1 TITAN Handheld XRF Spectrometer is among the lightest tube-basedhandheld XRF analyzers on the market today, according to its manufacturerBruker, at 1.5 kg, including battery. Fast analysis speed and exceptional accuracyare two key attributes that help define the S1 TITAN. Other innovative features