1、Designation: D6376 10 (Reapproved 2017)1Standard Test Method forDetermination of Trace Metals in Petroleum Coke byWavelength Dispersive X-ray Fluorescence Spectroscopy1This standard is issued under the fixed designation D6376; the number immediately following the designation indicates the year ofori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUnits formatting was corrected editorially in February 2017.1. Scope1
3、.1 This test method covers the X-ray fluorescence spectro-metric determination of total sulfur and trace metals in samplesof raw or calcined petroleum coke. Elements determined usingthis test method are listed in Table 1.1.2 Detection limits, sensitivity, and optimal element rangeswill vary with mat
4、rices, spectrometer type, analyzing crystal,and other instrument conditions and parameters.1.3 All analytes are determined as the element and reportedas such. These include all elements listed in Table 1. This testmethod may be applicable to additional elements or concen-tration ranges if sufficient
5、 standards are available to produceproper calibration equations.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
6、theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD
7、1552 Test Method for Sulfur in Petroleum Products byHigh Temperature Combustion and Infrared (IR) Detec-tion or Thermal Conductivity Detection (TCD)D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD5056 Test Method for Trace Metals in Petroleum Coke byAtomic AbsorptionD5600 Test
8、Method for Trace Metals in Petroleum Coke byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)D6969 Practice for Preparation of Calcined Petroleum CokeSamples for AnalysisD6970 Practice for Collection of Calcined Petroleum CokeSamples for AnalysisE11 Specification for Woven Wire Test
9、 Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 calcined petroleum coke, npetroleum coke that hasbeen thermally treated to drive off the volatile matter and todevelop crystalline structure.3.1.2 green petroleum coke, nsame as raw petroleumcoke.3.1.3 petroleum coke, na solid, carbonace
10、ous residueproduced by thermal decomposition of heavy petroleum frac-tions or cracked stocks, or both3.1.4 raw petroleum coke, npetroleum coke that has notbeen calcined.3.2 Definitions of Terms Specific to This Standard:3.2.1 alpha, ncorrection factor used to compensate forinterferences.3.2.2 analyt
11、ical sample, na representative fraction takenfrom a larger mass of petroleum coke and reduced by grindingto pass a 75 m (U.S. No. 200 mesh) sieve.3.2.3 pellet, na blend of dried sample and binder milledtogether and then formed into a pellet by pressure.3.2.4 reference samples, nsamples of known conc
12、entra-tions to be used in the calibration of the X-ray fluorescencespectrometer.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbo
13、n Material.Current edition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 1999. Last previous edition approved in 2010 as D6376 10. DOI:10.1520/D6376-10R17E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.o
14、rg. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with inter
15、nationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Summary of Test Method4.1 A representative sa
16、mple of petroleum coke is dried toconstant mass at 110 C 6 10 C and then crushed to pass a75 m (U.S. No. 200 mesh) sieve. A weighed portion of thisanalytical sample is mixed with stearic acid, or other suitablebinder, and then milled and compressed into a small, smoothpellet suitable for analysis. T
17、he pellet is irradiated by an X-raybeam. The characteristic X rays of the elements analyzed areexcited, separated, and detected by the wavelength-dispersiveX-ray spectrometer. These measured X-ray intensities areconverted to elemental concentration through the use of acalibration equation derived fr
18、om analyses of standard materi-als. This calibration equation defines the sensitivity and back-ground associated with a particular X-ray spectrometer.4.2 The K-alpha spectral lines are used for all of theelements determined by this test method.5. Significance and Use5.1 The presence and concentratio
19、n of sulfur and variousmetallic elements in a petroleum coke are major factorsdetermining the suitability of a coke for various purposes. Thistest method provides rapid means for measuring sulfur andcommercially important metallic elements in coke samples.5.2 This test method provides a guide for de
20、terminingconformance to material specifications for use by buyers andsellers in a commercial transfer of petroleum coke.5.3 Sulfur contents can be used to evaluate the potentialformation of sulfur oxides (SOx), a source of atmosphericpollution.6. Interferences6.1 Review all potential spectral interf
21、erences for the ele-ments listed in Table 2. Follow your manufacturers operatingguide to develop and apply alphas to compensate for theseinterferences.6.2 Compensate for inter-element effects by using alphas aspart of the regression procedure provided with spectrometersoftware.6.3 Changes in the sul
22、fur concentration in the sample affectsanalyte X-ray intensities. Therefore, determine the magnitudeof the sulfur effect on each metallic element and apply inappropriate correction.7. Apparatus7.1 Balance, capable of weighing 50 g 6 0.01 g.7.2 Hydraulic Press, capable of exerting a force of not less
23、than 276 MPa (40 000 psi).7.3 Mill or Grinder, capable of reducing 20 g of petroleumcoke to a sample passing 75 m (U.S. No. 200 mesh) in lessthan 10 min, without introducing contamination.7.4 Mixer/Mill, for blending sample and binder.7.5 Pellet Cup, Aluminum (optional), tapered to holdpressed pelle
24、ts.7.6 Pelletizing Die, for forming pellets of a diameter suit-able for use in the spectrometer.7.7 Sieves, 75 m (U.S. No. 200 mesh) as specified inSpecification E11.7.8 Drying Oven, capable of maintaining a minimum tem-perature of 110 C 6 10 C.7.9 X-ray Spectrometer, equipped for soft X-ray detecti
25、on ofthe K-alpha spectral lines for all of the elements determined bythis test method. For increased sensitivity, this instrument shallbe equipped with the following:7.9.1 Analyzing CrystalsThis choice is made based on theelement to be determined. The crystal selected should yieldoptimal sensitivity
26、 with minimum interferences. The samecrystal shall be used for both standards and unknowns. SeeTable 2 for recommended crystals.7.9.2 Detector, suitable for the determination of elements inquestion. Choices include gas-flow proportional, sealedproportional, and scintillation detectors.7.9.3 Optical
27、Path, in a vacuum.7.9.4 Pulse-Height Analyzer, or other means of energydiscrimination.7.9.5 Suitable X-ray TubeChromium, molybdenum,platinum, rhodium, or tungsten target and dual targets havebeen found suitable. The scandium tube is very advantageousfor light elements.8. Reagents and Materials8.1 Pu
28、rity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatTABLE 1 Applicable Concentration RangesElement Concentration Range, (mg/kg)Na 50500Al 50500Si 20500S, % 0.107.0Ca 20500Ti 10200V 202000Mn 10200Fe 201000Ni 20500TABLE 2 Suitable Instrumen
29、t Operating ConditionsElement2 Angle,DegreesABackground,DegreesAAnalyzingCrystalASodium 25.05 26.75, 24.35 Multilayer, 2d ;50Aluminum 145.13 143.13 PETSilicon 144.95 147.05, 142.85 InSbSulfur 110.68 113.18 GeCalcium 113.08 116.00 LiF (200)Titanium 86.13 84.13 LiF (200)Vanadium 76.93 78.93 LiF (200)M
30、anganese 62.97 60.97 LiF (200)Iron 57.52 59.02 LiF (200)Nickel 48.66 49.92, 47.40 LiF (200)AThe wavelength angles and analyzing crystals listed are suitable due to theirsensitivity and general industry acceptance.These choices are made based on theelement to be determined. Other instrument operating
31、 conditions can be used, butan attempt should always be made to use only those conditions yielding optimalsensitivity with minimum interferences. The instrument manufacturer should beconsulted for recommendations on optimal targets, crystal options, and anyconcentration limit restrictions on your un
32、it.D6376 10 (2017)12all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.3,4Other grades maybe used, provided they are of sufficiently high purity to permituse without diminishing the accurac
33、y of the determination.8.2 Detector GasP-10 gas (90 % argon, 10 % methane) isused with gas-flow proportional detectors.8.3 Pellet Binder MaterialStearic acid, or other suitablebinder, providing no spectral interferences shall be used.8.4 Reference Samples, of petroleum coke bracketing theelement ran
34、ges of the analytical samples. Commercial refer-ence samples of this type are available from several sources.9. Sampling and Preparation of Test Specimens9.1 Basic AssumptionsAll petroleum coke samples exam-ined using this test method shall be analytical samples repre-sentative of a green or calcine
35、d coke production lot orshipment. Practices D4057, D346, D6969, and D6970 shall befollowed. The analytical sample shall pass a 75 m (U.S. No.200 mesh) sieve and shall be of sufficient quantity to providesample for all testing and analyses planned for the particular lotof petroleum coke. To provide f
36、or possible replicate determi-nations of the sulfur and metallic contents by this test methodand for a retain sample, an analytical sample shall be 50 g ormore for this test alone.NOTE 1Results are particle dependent, and erroneous data may becollected if analytical samples contain particles varying
37、 significantly insize from those in reference samples. Measurements may be necessary toensure the equivalence of analytical samples and reference samples. Themost difficult problems occur when there are coarse petroleum cokesamples and finely ground reference samples. In this case, it is best togrin
38、d the analytical samples, achieving a size distribution similar to thereference samples.9.2 Types of Samples:9.2.1 Reference SamplesThese samples shall be similar tothe analytical samples in composition and physical properties.A wide range of concentrations is required for inter-elementeffect detect
39、ion when regression software is used to analyzereference data. Elemental concentrations shall bracket thevalues expected in the analytical samples.9.2.2 Analytical SamplesSamples whose sulfur and me-tallic contents are to be determined.9.3 Typical Preparation of Standards and Test Specimens:9.3.1 Dr
40、y a sufficient portion of the analytical sample toconstant mass in an oven at 110 C 6 10 C to obtain at least5g.9.3.2 Weigh 5 g 6 0.01 g of the dried analytical sample.9.3.3 Add 1 g 6 0.01 g of binder and mill for a minimum of20 s. Binder/coke ratio shall remain constant for samples andstandards.9.3
41、.3.1 Suitable grinding times to produce particles passinga 75 m (U.S. No. 200 mesh) sieve depends on the type ofgrinder used and coke variations. Further grinding time im-pacts element intensities. It is important that grinding time bethoroughly investigated and optimized.NOTE 2It is essential that
42、the same sample preparation procedure(including sample mass, binder mass and ratio, grinding, and so forth) befollowed precisely for all analytical and reference samples. Even a smallchange in procedure requires making all new reference samples match thechanged procedure. All reference samples and a
43、nalytical samples usedwith them shall be prepared in exactly the same manner.All weighings areto be made to the nearest 0.01 g.9.3.4 Place the pellet cup in the die mounted on thehydraulic press. Transfer sufficient ground mix to this cup toproduce a pile of maximum height above the cup lip. Handpac
44、k with a flat spatula until the ground mix is level with thecup lip.9.3.5 Apply adequate pressure to achieve a stable pellet.Allow adequate time to reach a pressure of approximately276 MPa (40 000 psi) and hold for a minimum of 5 s.9.3.6 Release the pressures slowly, and remove the pelletfrom the di
45、e. (WarningRelease the pressure slowly to avoidpossible damage to the pressure gauge.)9.3.7 Inspect the pellet surface to ensure that it is smoothand free of cracks. The cylindrical pellets should be 3 mm to7 mm thick.9.3.8 When the pellet is too thin, repeat 9.3.2 9.3.7 usingabout 20 % more ground
46、mix.9.3.9 Clean the outside surface of the pellet cup, using aclean cloth or tissue. If the pellet is to be stored, it is importantto properly identify it and store it in a dry place.9.3.10 Unused test specimens prepared and stored as aboveare generally stable for years. Reference sample pellets can
47、 beused daily for establishing instrument conditions. If changesgreater than 3 % (10 % for silicon) are observed for thecalculated concentrations for any element in a used pellet, thereference sample pellets shall be prepared again. If deviationspersist, recalibrate the instrument.10. Preparation of
48、 Apparatus10.1 Follow manufacturers instructions for the initialassembly, conditioning, and preparation of the XRF unit.10.2 Follow the manufacturers control setting and opera-tion instructions.10.3 Peak and Background Intensity MeasurementsA de-cision on counting time is made after analyzing all re
49、quiredreference samples and after the sensitivity is known. A sug-gested strategy for counting time based on reference samples isas follows:10.3.1 Counting time is derived from:Relative error, % 5 100/Tt!31/Rp!2 Rb! (1)3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand Na
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