Analyzing Precious Metals - SPECTRO/Nu EXTRANET
When results matterA WHITE PAPER FROMSPECTRO ANALYTICAL INSTRUMENTSAnalyzing Precious MetalsIntroductionPrecious metals require — and reward —Three modern techniques offer widely usedcareful analysis. Their high monetary valuesolutions. Energy-dispersive X-ray fluorescencemeans that purity is a prime consideration(ED-XRF) and optical emission spectrometry (OES)when trading in these metals or productscan be used without specialist analytical trainingmade from them. Different alloys must beto rapidly and accurately analyze bullion, jewelry,identified and their composition verified.and alloys. A variation of OES, inductively coupledAdulteration, while not always easy to detect,plasma optical emission spectrometry (ICP-OES),can dramatically affect value.is an ideal tool for the analysis of bulk materialssuch as ores, and for the determination of traceAnalysts face various difficulties. The scope ofimpurities.precious metals analysis extends from tracelevels to 100%. Most of these metals areSeveral instruments available from SPECTROresistant to dissolution by all but the strongestAnalytical Instruments represent the state of theacids. Some traditional analytical methods likeart in these techniques. This paper describes theirfire assay are time-consuming and demand aapplication to precious metals analysis.high level of skill.
CURRENCY TO CHEMISTRY:THE VALUE OF PRECIOUSMETALS(ppb) in the earth’s crust. Silver is the mostabundant, at about 75 ppb, or 0.0000075%.This compares with aluminum at around8%, or iron at 5%. Even “rich” depositsThe following are traditionally classified asof precious metals have concentrationsprecious metals: gold, platinum, iridium,measured in parts per million (ppm).palladium,rhodium,However, their value is not necessarilyruthenium, and rhenium. All are metallicproportional to scarcity. Some are traded aselements that have achieved high monetarycommodities, and acquire inflated values viavalue due to their rarity and specialspeculation in times of financial uncertainty.properties.Indeed, four precious metals are regardedosmium,silver,as convertible currencies and possess ISOWhile the latest-known, rhenium, was4217 currency codes: gold, silver, platinum,discovered in 1925, gold has been knownand palladium.since antiquity, largely because it is found innature as a free metal. Gold is the exemplarOtherof an important characteristic of this class:describe these elements. Noble metals areresistance to corrosion and oxidation. Thischaracterized by their high resistance toprovides permanence, luster, and suitabilitycorrosion. These can be precious metals,for jewelry and coinage. Other preciousand sometimes nonprecious metals such asmetals like platinum and silver also occurmercury. Platinum group metals or elementsnaturally in metallic form, often alloyed withare also known as PGMs or PGEs. Theseother metalssix transition elements — platinum, iridium,termsaresometimesusedtopalladium, osmium, rhodium, and rutheniumExtractioncanbeverydifficult,with-— are clustered together in the periodiconly tiny concentrations present in mosttable, have broadly similar properties, anddeposits. Precious metals are extremelytend to occur in the same mineral deposits.rare — typically only a few parts per billion2Analyzing Precious Metals
Whole industries exist to recover valuablemetals from secondary sources such asscrap jewelry, electronic wastes, and junkedvehicle catalysts. At the other end of theproduction chain, it’s economically viable toexploit ores with quite low precious metalcontent. Improved extraction technologyand higher prices make it practical to reworkold mine dumps, extracting metals leftbehind by older, less efficient extractionmethods. Evaluating these sources requiresanalysis to the sub parts-per-million level.Karats and ConventionsMineral deposits worthy of extraction existPrecious metals in bulk that are traded byin few locations. Russia and South Africaweight are known as bullion. This term alsoare the world’s major sources of gold andapplies to gold coinage when the priceplatinum.depends on the purity and mass of the coin,Wheretheyoccur,preciousmetals are often found alloyed with eachnot its face value.other. They are also found in deposits ofother base metals such as copper and nickelIn jewelry, and other consumer goods suchthat are mined in huge quantities, justifyingas silver tableware, a number of conventionsthe extraction of the precious metals ashave developed to describe the purity of theby-products.havemetal. These are more familiar within theimproved, extraction and purification areindustry than the concentration units usedstill complex, capital-intensive processes,by analysts.Althoughmethodsfurther increasing prices.The essential measurement of gold is usuallyEstimates suggest that up to 30% of today’sexpressed in karats — a unit of purity — wheregold supply is recycled metal. Besidespure gold (or fine gold) is defined as 24 kt.its financial merits, recycling is driven by(Note that a carat — a unit of mass, where 1legislation: in the EU, the Waste Electroniccarat equals 0.2 gram — instead expressesand Electrical Equipment (WEEE) Directivethe weight of a precious stone, particularly arequires that suppliers and users of tdisposal at the end of the equipment’s usefulPure 24 kt. gold is too soft to be practicallife is environmentally sound. Recoveryfor jewelry, being liable to scratching orof precious metals is often part of thatdeformation. So gold is often mixed withdisposal process. Similarly, the EU’s End-other metals; silver and copper are itsof-Life Vehicles (ELV) Directive requires thatmost common alloying elements. Carefullypotentially polluting components (includingcontrolling concentrations can producecatalytic converters, which contain platinumalloys that have the appearance of gold,and often palladium and rhodium) bebut quite low actual content. Metals such asremoved and properly disposed of by anzinc are also used in low concentrations, toauthorized processor.increase hardness. These alloys may stillAnalyzing Precious Metals3
be sold as “gold,” although most countriesconsumer: gold contacts are a familiarset a limit for gold content below which thefeature of printed circuit boards. Gold,word cannot be applied. Another popularplatinum, and palladium are utilized injewelry alloy is white gold, in which golddental alloys for their insolubility andis alloyed with metals such as palladium orpermanence. These and a host of othernickel. When used in jewelry, white goldapplications of precious metals not onlyis sometimes rhodium-plated; rhodium isrequire raw materials with analyzed com-also “white,” and if overlooked could causeposition, but also produce waste thaterrors with some analytical techniques.can be treated to recover these valuablematerials.% w/wfinenesskarat99.999999.9924THE ROLE OF ANALYSIS91.67916.722Elemental analysis plays a central role in75.075018the precious metals industries. Typical58.558514tasks include:33.33338 Verrification of purity and composition,Platinum is also widely used in jewelry,includingalloyed with other PGMs such as palladiumpurposesand iridium.for Identification of alloys Measurement of impuritiestradingand adulterationMost platinum jewelry is designated with apurity code of 950, or 95% pure; commonhallmarking, Analysisofscrapandprocessedmaterials during recyclingplatinum alloys are Pt950/Ru, Pt950/Ir,Pt900/Ir, and Pt950/Co. A common silver Process controlalloy, known as sterling silver, is 925, or Prospecting92.5% silver; coin silver is 900 or 90%.Whatever convention is used, in mostThese analyses involve a huge range ofcountriesareconcentrations, from pure metal to sub-stamped with a hallmark to indicate theirppm. They also encounter a wide rangepurity.of sample types, from bullion to jewelrypreciousmetalartifactsto “sweeps” from working areas to scrapNon-Jewelry Applicationsitems to bulk geological samples.The chemical and physical properties of4precious metals are useful in many otherA common requirement: quick assessmentapplications. For example, despite theirof the composition, and hence the value,apparent inertness, PGMs (platinum andof bullion, coins, and jewelry. In trading,palladium in particular) are excellentan answer should ideally be availablecatalysts.(usedon the spot. Gold, for example, can bein emission control systems) accounttraded via a number of channels, includingfor around half the platinum mined;jewelers, dealers, pawn shops, and so on.PGM catalysts are also used in chemicalFor small quantities, payment may be onsynthesis and petroleum refining. Thethe basis of hallmarks, or on the simpleelectronics industry is another majortests described below. Eventually, theAutomobilecatalystsAnalyzing Precious Metals
scrap is melted, cast into bars, and soldimmediately,to a refiner, often in the form of lots: barswithout special analytical skills, would beof impure metal that might contain 40%–ideal. Clearly, it’s a distinct disadvantage60% gold mixed with silver and otherfor any party in a transaction to rely onmetals.time-consuming and expensive externalTwo major sources of recycled preciousanalysis, or on cheaper but perhaps lessmetals are auto catalysts and electronicaccurate internal testing. Unfortunately,waste (e-waste). Components containingtraditional testing methods are either tooprecious metals (e.g., catalytic convertersinaccurate or time-consuming, or requireor printed circuit boards) are removed anda suitably equipped laboratory.in-house,bypersonnelsent to specialist treatment companies. Inthe case of catalytic converters, the PGMTraditional Analysis Methodscatalyst is usually distributed on ceramicBy nature, precious metals are difficult togranules at up to 0.2% metal content.analyze. The metals and jewelry tradesThis is removed from its steel canisterhave long relied on some simple tests, butand milled to a fine powder containingthese can give only approximate results forthe PGMs, for further processing. Printedelemental composition:circuit boards and similar electronic wasteproducts are usually shredded, then The acid test. With some variation, thesubjected to smelting and/or leachingbasic test involves rubbing the sampleprocesses to extract precious metals.on an abrasive stone to remove a minutePrices are based on analyses of thistrace of metal, which is left as a mark onpowdered or shredded material.the stone. This trace is then tested forsolubility (indicated by a color change) inUltimately, payment must be based onacids of different strengths, each matchedanalysis. Results that are of sufficientto a different karatage of gold. This testaccuracy, and that can be obtainedcan also distinguish some silver grades,Analyzing Precious Metals5
and provide a yes/no test for platinum.An extension of the fire assay technique,It’s cheap but very crude, limited toused to evaluate ores and other bulkdifferentiating between commonly usedmaterials containing low concentrations ofjewelry grades.precious metals, involves pre-concentratingprecious metals by fusing the sample with Conductivity.thea flux and a collector, such as lead for goldelectrical conductivity of the sample. AThistestmetersor nickel for PGMs. Precious metals areconductive solution or paste is applied toscavenged from the melt by the collectorthe sample to establish a good electricalmetal; other materials are fused into a slag.contact.On cooling, the metals solidify as a button.This is easily separated from the glassyNeither of the above tests provides moreslag, and can then be subjected to fire assaythan an indication of elemental composition.or chemical analysis. Using this method,Note that both are also unsuitable forprecious metals can be measured downanything other than metallic samples.to ppb levels. However, sampling must bedone with great care to avoid errors. Fire assay. This is the traditional methodfor the accurate determination of theFortunately, modern instrumental methodspurity of gold. The weighed sample ishave revolutionized the analysis of preciousheated with lead to around 1200 C in ametals. They can achieve much moreporous crucible, made of compressedaccurate results than acid or conductivity,bone ash or magnesium oxide. Thisbut in a fraction of the time needed for fireprocess is known as cupellation. Lead andassay.other base metals are oxidized, and theoxides absorbed into the crucible, whilethe precious metal remains behind. Anysilver in the solidified metal is dissolvedin acid, and the remainder — gold — isweighed.A skilled fire assay operator s of better than 0.05%. However,the process takes several hours, so it’sunsuitable when spot decisions must bemade about an article’s value. Althoughit’s very accurate for simple gold/silver/copper jewelry alloys, more complex alloyscontaining other precious metals requirefurther analysis. Fire assay is also usuallyregarded as a bulk analysis method, andmay not be economical when trying toevaluate an individual jewelry item.6Analyzing Precious Metals
MODERN ELEMENTAL ANALYSISTECHNOLOGIESThe techniques differ in the type of energyEnergy-dispersive X-ray fluorescence (ED-also governs the type of samples that canXRF) and optical emission spectrometrybe handled), and in the technology used to(OES) can be used by operators withoutanalyze and detect the emitted radiation.analytical knowledge to return accurateThe following table summarizes the mainanalyses of even complex precious metalfeatures of the techniques and their uses inalloys — in seconds rather than hours.precious metals analysis:used to excite the sample atoms (whichInductively coupled plasma optical emissionspectrometry (ICP-OES) is an excellent toolfor the analysis of bulk materials like ores,TechniqueExcitationSpectrumDetectionTypical AnalysesAnalysisand for the determination of trace impurities.ED-XRFX-rays fromSolid state Silicon Drift DetectorPurity of solid metalsAll three methods work on the spectroscopiclow power(SDD) or Si PIN Detector, capable ofeg bullion, pin samples,principle, which relies on the internal(40 W or less) discriminating between emissionscoins, jewelry.structure of the atoms of the material beingX-ray tubePM’s in bulk recycledfrom different elements.analyzed. The atoms of the sample arematerials catalysts,excited by an external source of energy,electronic wasteElectric arcOptical poly-CCD and/orImpurities in metals, egenergy level of the electrons in the sampleor sparkchromator usingphotomultiplierbullion, pin samplesatoms. This excited state is unstable, sodischargediffraction gratingwhich is absorbed by and raises theOESInductivelyOptical poly-CCD and/orTraces of PM’s in firestate, re-emitting energy as they do so. Thecoupledchromator usingphotomultiplierassay “buttons”. Impuri-energy emitted, or emission spectrum, isplasmadiffraction gratingthe electrons rapidly return to their normalICP-OESties in PM’s and alloys,characteristic of the elements contained inthe sample; its intensity is proportional totheir concentration.ED-XRF Analysis of Precious MetalsED-XRF is the most widely used analyticaltechnique in the precious metals industry.Unlike many spectroscopic techniques, itdoesn’t require the sample to be atomizedto enable excitation. So it can analyze solidsamples directly. Unlike methods requiringfusion or dissolution, it’s nondestructive.This is critical to its usefulness in analyzingjewelry and other valuable itemswithout damage or removal ofprecious metal. ED-XRF is alsocapableofquantifyingallthesample’s elements of interest in asingle measurement. Finally, it’s idealfor the detection of counterfeitingand for other forensic work.The spectrometric principle in action: X-rays excite the innerelectrons, which emit characteristic energy as they return to normal.Analyzing Precious Metals7
SPECTRO MIDEX and SPECTROCUBEUsersoftheSPECTROandarea high-resolution silicon drift detectorED-XRF(SDD). In addition, a high-speed readoutspectrometers from SPECTRO Analyticalsystem provides an ultra-high count rateInstruments report that these productscombined with excellent resolution. Thisapproach fire assay in terms of precisealso contributes to the systems’ outstandingresults, while maintaining all XRF advantages.sensitivity, which is the basis for goodSPECTROCUBEMIDEX1.2 mm. The analyzers also feature a large-small-spotprecision and also good yseparating the spectral lines of individualelements in an alloy. By contrast, the highresolution achieved by SPECTRO MIDEX orSPECTROCUBE shows the clear separationof respective lines.These midrange analyzers have recentlybeen improved or newly launched with anumber of technical innovations and userfriendly features. They are standard tools forlaboratories where better precision or fasteranalysis is needed — in testing offices, assayoffices, hallmarking centers, precious metalrefineries, and more.Components of both instruments include aTypical part of spectra from a yellow gold, a white goldand a rose gold sample40 W molybdenum X-ray tube generatinga standard measurement spot size ofInhallmarkingcenters,theSPECTROMIDEX can deliver scanning results inas little as 15 seconds — still with goodprecision and accuracy. On the other hand,refiners may choose to take advantageof the unit’s improved sensitivity to allowfor lower detection limits for some traceconcentrations — thus enabling refiners toavoid overpayment due to overmeasuringgold content. This is achieved within theshortmeasurementtimesreachedbyprevious models.8Analyzing Precious Metals
SPECTRO MIDEX was specifically designedCorrelation for the Analysis of Au in Au Alloys (SPECTROCUBE)to accurately analyze small objects such asjewelry. An optional ��s standard 1.2 mm spot to allowmeasuring point sizes from 1 mm to 4 mm.(Larger spots can prove advantageousfor silver, which, unlike gold, may notbe uniformly homogenous throughout asample’s mass.) For irregularly shapedsamples (such as slanted bars, highrelief jewelry, or ring inner surfaces), the100Au concentra on analyzed in %collimatorR² 0,9999908070605040305 mm working distance permits focusing304050on sample points at varying heights. Theintegrated color video system allows clearimaging and positioning of the sample, plusfor high-throughput applications such ashallmarking centers. With its bottom upgeometry, positioning of jewelry samplesis fast and simple. High throughput is alsosupported by measurement times as low as 15seconds — twice as fast as other instrumentsin its class. So the analyzer easily allowstesting of several hundred samples per day.A software-controlled collimator changerallows the user to choose from a range ofdifferent collimator dimensions (down toa spot size of 0.2 mm). SPECTROCUBEoptions and analytical performance arethe same as those of the SPECTRO MIDEXAnalyzing Precious Metals708090100Repeatability for Gold in gold alloys (SPECTRO MIDEX)documentation of the testing spot.SPECTROCUBE was specifically designed60Au concentra on given in %AuAgCuZnNiReplicate 175.03 0.053.029 0.02514.67 0.022.197 0.0105.072 0.012Replicate 275.05 0.053.028 0.02414.67 0.022.179 0.0105.057 0.012Replicate 375.08 0.052.981 0.02414.67 0.022.199 0.0105.071 0.012Replicate 475.04 0.053.016 0.02514.68 0.022.181 0.0105.083 0.012Replicate 575.08 0.052.990 0.02414.67 0.022.195 0.0105.066 0.012Replicate 675.04 0.053.008 0.02514.66 0.022.215 0.0105.074 0.012Replicate 775.06 0.052.991 0.02514.67 0.022.221 0.0105.049 0.012Replicate 875.09 0.052.964 0.02414.67 0.022.212 0.0105.056 0.012Replicate 975.03 0.053.009 0.02514.67 0.022.215 0.0105.072 0.012Replicate 1075.04 0.053.015 0.02514.69 0.022.191 0.0105.055 0.012Average75.053.00314.672.2005.066Std dev0.020.0210.010.0150.011Gold Alloys (SPECTRO MIDEX)SampleAuAgCuNiZnBAM EB 506BAM EB 507BAM EB 508given in %58.56 0.0675.10 0.1175.12 0.11analyzed in %58.71 0.0375.05 0.0375.16 0.03given in %3.90 0.053.02 0.0524.90 0.05analyzed in %3.86 0.013.00 0.0124.80 0.03given in %35.65 0.0614.69 0.05analyzed in %35.50 0.0114.67 0.01given in %4.99 0.04analyzed in %5.06 0.01given in %1.891 0.0182.107 0.016analyzed in %1.921 0.0052.160 0.0059
spectrometer.These instruments are factorycalibrated and validated for an exceptionallywide range of precious metals samples.Their SPECTRO XRF Analyzer Pro operatingsoftware was recently optimized via thirdparty testing and user input to increaseease and effectiveness. The instruments’SPECTRO FP fundamental nt accuracy up to 100% concentrationlevels, but can analyze completely unknownprecious metal alloys.To demonstrate its accuracy, SPECTROResults of a typical gold sample after a measuring time of a few seconds.MIDEX was used to analyze a variety ofthan 26.7 lb (12 kg), rtifieddeliverslaboratory-qualitycompositions. The measurement time forelemental analysis. It’s capable of identifyingthese analyses was 60 seconds per sample.and analyzing precious metals in a matterof seconds. Samples are analyzed for allSPECTROSCOUTrelevant metals simultaneously, with aSPECTROSCOUT is a fully portable, lower-measuring spot of 1 mm. (An option allowscost alternative to the SPECTRO MIDEX,a larger 2 mm spot, useful, for example, inoperating on the same XRF principles.accommodating inhomogeneities in ,application-package-specific internal libraryfor instant identification of precious metalsand their alloys, or carry out a completeelemental analysis in the same way asSPECTRO MIDEX. Results are displayed onthe touchscreen or can be downloaded toa computer; the first analysis is available inas little as a few seconds. Good results canbe obtained for additional elements, even inlow concentrations such as those found inrefining metals, with a measuring time of 120to 300 seconds.SampleKtCertified Au Value[%]SPECTRO MIDEX(60 sec) analyzedAu Value [%]SPECTROSCOUT(300 sec) analyzedAu Value [%]NCS HC 549248.435 0.0835.29 0.0434.75 0.06NCS HC 549082291.68 0.0891.61 0.0891.58 0.07NCS HC 549012499.994 0.037100 0.1099.99 0.08Accuracy is comparable to SPECTRO MIDEX analyzer.10SPECTRO XEPOSEven after preliminary processing, concentrations of precious metals in bulk samplessuch as catalysts and electronic wastes aremuch lower than in jewelry scrap, and require more sensitive techniques for analysis.While the SPECTRO MIDEX, SPECTROCU-Analyzing Precious Metals
BE, and SPECTROSCOUT analyzers have li-approximately 100 μm or smaller, and themits of detection in the ppm range, samplingresulting powder is poured into a sampleerrors could still arise, due to nonhomoge-cup or pressed into a pellet after mixingneous samples and relatively small measure-with a binder. The SPECTRO XEPOS resultsment windows. Users tasked with these ap-below were obtained with NIST referenceplications can turn to the high-end SPECTROmaterials — and show excellent agreementXEPOS HE XRF spectrometer— SPECTROwith the certified values.Analytical’s most powerful XRF analyzer.ElementCertifiedValues [mg/kg]Analyzed Values[mg/kg]Rh135.1 1.9137.1 1.0Pd233.2 1.9235.4 0.6Pt1131 111124 2Analysis results for validation sample NIST 2557 withSPECTRO XEPOS:ElementCertifiedValues [mg/kg]Analyzed Values[mg/kg]51.2 0.547.2 0.4Pd326 1.6312.8 0.6Pt697.4 6.3676 1.7RhIts innovative components include a 50 W /60 kV X-ray tube, an ultra-high-count SDD,Analysis results for validation sample NIST 2556 withSPECTRO XEPOS:and unique adaptive excitation technology.So it can furnish previously impossibleOES Analysis of Precious Metalssensitivity boosts of up to 10x previousRefiners and alloy producers have particularmodels — optimized to target preciousrequirements in determining precious metalsmetals elemental groups. It can also achieveimpurities. Optical emission spectrometrynotably low limits of detection (LODs).(OES) is an ideal technique for their needs.This is a key advantage when analyzing forLike ED-XRF, it can be used directly onthe relatively low concentrations found inmetallic samples such as pins. It is, however,automotive catalysts.notcompletelynondestructive;atinyamount of material is atomized by the sparkBesides high resolution and sensitivityused to excite the sample.plus low LODs, SPECTRO XEPOS canprovide reduced measurement times, lowSPECTROLABconsumables use, and excellent long-termThe SPECTROLAB high-performance arc/stability. Compared to small-spot excitation,spark OES analyzer offers a number ofthe analysis area of the sample is largeradvantages for this work, even whenusing the SPECTRO XEPOS, especially whencompared to other OES instruments. Theutilizing optional sample spinning duringSPECTROLAB’smeasurement. This helps to reduce effectssystem embodies several innovations infrom inhomogeneities.excitation, optics, detection, and softwareExample: To analyze recycled automotiveto optimize analytical performance andcatalyst,operator convenience. In particular, itsthesampleisAnalyzing Precious Metalsgroundtouniquehybridoptical11
hybrid version combines photomultiplierand low detection limits achievable withtube (PMT) and charge coupled deviceSPECTROLAB — combined with its speed(CCD) sensor technology for exceptionallyof analysis, simple sample preparation, andaccurate, simultaneous analysis of preciousease of use — make it suitable for refiningmetals. The unit provides ultra-high speedquality control and similar tasks.of measurement, ultra-low LODs, ultimateelemental flexibility, outstanding stability,SPECTROLAB can be optimized for preciousand affordable cost of ownership.metal matrices of interest: gold, silver,platinum, palladium, and ruthenium. TypicalRefineries must produce precious metals ofLODs (in ppm) of a range of elements invery high purity as a starting point for newdifferent precious metal bases are shown inalloys. The improved background correctionthe accompanying table.ElementGold Base[mg/kg]AgPlatinum Base[mg/kg]Palladium Base[mg/kg]0.060.060.2Al0.060.180.2As0.7AuSilver 50.1Note: This data is from the SPECTROLAB Application Note Arc/Spark Nr. 43/5.12Analyzing Precious Metals
ICP-OES Analysis of Precious MetalsSPECTRO ARCOSDue to its very high sensitivity and wideThe high-end SPECTRO ARCOS simul-dynamic range, inductively coupled plasmataneous ICP-OES spectrometer representsoptical emission spectrometry (ICP-OES)the latest state-of-the-art technology for theis a popular technique for the analysismost demanding elemental analyses in theof exploration samples such as ores andprecious metals field.stream sediments, and for the measurementof impurities in precious metals. AdvancedICP-OES is particularly suitable for theICP-OES instruments can achieve limits ofmeasurement of traces of impurities in golddetection (LODs) in the parts per billion (ppb)and other precious metals. One feature of(μg/kg) range.SPECTRO ARCOS is especially useful for thisapplication: an option for true axial and radialBecause ICP-OES requires putting sampleviewing of the plasma in a single uniqueMultiViewconfigurationcan be dealt with more easily than in ED-provides both enhanced sensitivity for traceXRF or OES analysis, as long as samplinganalysis and high stability for the analysis ofproceduresmajor spectralInresolution,and detection must be optimized for bestLimits of detection achieved on goldperformance.samples by SPECTRO ARCOS are shown inthe accompanying table.SPECTRO GENESISThe SPECTRO GENESIS is a compact, fullyBecauseofitswidedynamicrange,simultaneous spectrometer with the benefitsMultiView can also be used to measureof ICP-OES technology, but the affordabilitymajor components in alloys. An internalof flame absorption spectrometry (AAS)standard plus a bracketing method is appliedinstruments. It provides simple calibrationto compensate for fluctuations and otherand an extremely wide dynamic range.variables, and to achieve the necessaryIt’s also much faster than AAS or evenaccuracy and precision. ISO 11494 and ISOnonsequentialIts11495 are standard methods — for platinumhigh-throughput design is optimized forand palladium analysis respectively — thatapplications requiring rapid, highly accuratedescribe bracketing, and the use of yttriumanalysis of more than 50 samples and 10as an internal standard.ICP-OESmodels:elements per day.Analyzing Precious Metals13
For the most challenging precious metalsElementWavelength[nm]LOD 3s[mg/kg]Ag224.6410.18and other innovations to deliver exceptionalAl396.1520.07resolution and sensitivity, highest speed,As193.7591.8applications, SPECTRO ARCOS features thehighest-power generator, exclusive optics,best-in-classstability,long-termsavings, and unparalleled ease of W20
for jewelry and coinage. Other precious metals like platinum and silver also occur naturally in metallic form, often alloyed with other metals Extraction can be very difficult, with . only tiny concentrations present in most deposits. Precious metals are extremely rare — typically
SPECTRO-UV6 Series, Double Beam Spectrophotometer Model SPECTRO-UV61 SPECTRO-UV61PC SPECTRO-UV63 SPECTRO-UV63PC SPECTRO-UV61S SPECTRO-UV61PCS Wavelength range 190-1100nm Spectral bandwidth 1.8NM 1nm 0.5/1/1/4nm Optical system Double beam, grating 1200 lines
Metals vs. Non-Metals; Dot Diagrams; Ions Metals versus Non-Metals Dot Diagrams Metals are on the left side. Non-metals on the right. Metals tend to lose electrons. Non-metals gain them tight. Dot Diagrams (sometimes known as Lewis dot diagrams) are a depiction of an atom’s valence elect
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Metals and Non-metals CHAPTER3 In Class IX you have learnt about various elements.You have seen that elements can be classified as metals or non-metals on the basis of their properties. n Think of some uses of metals and non-metals in your daily life. n What properties did you think of while categorising elements a
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