1、Designation: D5056 04 (Reapproved 2010)Standard Test Method forTrace Metals in Petroleum Coke by Atomic Absorption1This standard is issued under the fixed designation D5056; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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.1. Scope1.1 This test method covers the analysis for the commonlydetermined trace metals (aluminum, calcium, iron, nickel,silic
3、on, sodium, and vanadium) in laboratory analysis samplesof raw and calcined petroleum coke by atomic absorptionspectroscopy.1.2 The elemental concentration ranges for which this testmethod is applicable and the limits of detection of this testmethod are listed in Table 1.1.3 The values stated in SI
4、units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory
5、limitations prior to use. For warningstatements, see Sections 8-10.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate Analyt
6、icalMeasurement System PerformanceD1193 Specification for Reagent Water3. Summary of Test Method3.1 A representative sample of the petroleum coke is ashedat 525C under specified conditions. The ash is fused withlithium tetraborate (Li2B4O7), or lithium metaborate (LiBO3).The melt is dissolved in dil
7、ute hydrochloric acid (HCl), and theresultant solution is analyzed by atomic absorption spectros-copy for the following elements: aluminum, calcium, iron,nickel, silicon, sodium, and vanadium.4. Significance and Use4.1 The presence and concentration of various metallicelements in a petroleum coke ar
8、e major factors in the suitabilityof the coke for various uses. This test method provides a meansof measuring the amounts of those metallic elements in thecoke sample.4.2 The test method provides a standard procedure for useby the purchaser and seller in the commercial transfer ofpetroleum coke to d
9、etermine whether the lot of coke meets thespecifications of the purchasing party.5. Interferences5.1 Spectral interferences can occur when using other thanthe recommended wavelength for analysis or when usingmulti-elemental hollow cathode lamps.6. Apparatus6.1 Furnace, electric, capable of regulatio
10、n of temperatureat 525C 6 10C.6.2 Magnetic Stirring Hot Plate.6.3 Platinum Dish, 50 to 58-mL capacity.6.4 Platinum Dish, 150 to 200-mL capacity.6.5 Platinum-Tipped Tongs.6.6 Furnace, electric, capable of regulation of temperatureat 950 6 10C or a Meker type forced air burner.6.7 Atomic Absorption Sp
11、ectrophotometer (AAS), equippedas follows:6.7.1 Background Correction, using either a deuterium (D2)arc background corrector or other comparable simultaneousbackground correction system.6.7.2 Burner Head, capable of supporting a nitrous oxide-acetylene flame.6.7.3 Burner Head, single or multiple-slo
12、t, capable of sup-porting an air-acetylene flame.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved May 1, 2010. Published May 2010. Originallyappr
13、oved in 1990. Last previous edition approved in 2004 as D505604. DOI:10.1520/D5056-04R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summ
14、ary page onthe ASTM website.TABLE 1 Applicable Concentration Ranges and Limits ofDetection on a Dried Original Sample BasisElementConcentrationRange (mg/kg)LimitDetection (mg/kg)Aluminum 15 to 105 5.0Calcium 20 to 225 1.0Iron 150 to 500 1.5Nickel 5 to 200 1.5Silicon 90 to 420 20Sodium 15 to 115 0.2V
15、anadium 5 to 500 2.01Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.7.4 Hollow Cathode Lamps, one for each of the elementsto be analyzed: aluminum, calcium, iron, nickel, silicon,sodium, and vanadium.NOTE 1Multi-elemental lamps can
16、 also be used; however, spectralinterferences are possible (see 5.1).7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the Ame
17、rican Chemical Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto wat
18、er shall be understood to mean reagent water as definedby Type II of Specification D1193.7.3 Hydrochloric Acid, Solution 1, 20 % by volume (20 mLof concentrated HCl diluted to 100 mL with Type II reagentwater).7.4 Lanthanum Additive, Solution 2, 100 g/L lanthanum(dissolve 175 g LaCl3in water and dil
19、ute to 1 L with water).7.5 Lanthanum Chloride (LaCl3) powder (high purity).7.6 Lithium Tetraborate (Li2B4O7), powder (high purity),or Lithium Metaborate (LiBO3), powder (high purity).7.7 Standard and Sample Dilution Additive, Solution3Weigh 40.0 g, to the nearest 0.1 g, of Li2B4O7into a 150 to200 mL
20、 platinum dish, fuse with a Meker type burner to forma liquid, and cool. Alternatively, heat in a furnace at 950 610C for 10 min or until a liquid forms. Place the cooledplatinum dish containing the fused recrystallized Li2B4O7, anda magnetic stirring bar into a 2-L beaker. Add 1000 mL ofSolution 1
21、(20 % HCl). Heat and stir the solution on a magneticstirring hot plate until the melt completely dissolves. Afterdissolution, remove the platinum dish with a glass rod. Rinsethe platinum dish and glass rod with water into the lithiumborate solution. Immediately transfer the warm solution quan-titati
22、vely to a 2-L flask. To avoid crystallization add about 100mL of water; stir the solution and cool to room temperature.Add 400 mL of Solution 2 (lanthanum additive) and mix.Dilute to 2000 mL with water, mix thoroughly, and vacuumfilter the entire solution through Dow filter paper.NOTE 2Fifty millili
23、tres of Solution 3 contains1gLi2B4O7,25mLofSolution 1, 20 % HCl, and 10 mL of Solution 2, lanthanum additive.7.8 Standard Stock SolutionsPrepare standard stock solu-tions from high purity (99.9 % or better) metals, oxides, orsalts. Stock solutions of 1000 ppm (mg/L) for each metal areneeded for prep
24、aration of dilute standards in the range from1.0 to 50 ppm (mg/L). Working standards containing alumi-num, calcium, iron, nickel, silicon, sodium, and vanadium inconcentration ranges below 10 ppm (mg/kg) are to be prepareddaily to ensure stability.7.9 Quality Control (QC) Samples, preferably are por
25、tionsof one or more petroleum coke samples that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity of the testing process asdescribed in Section 13.NOTE 3Commercially available standards and other reagent solutionsmay be used in place of labora
26、tory preparations.8. Sample Preparation8.1 Crush and divide the initial sample to obtain a labora-tory analysis sample. Crush to pass a No. 60 (0.250 mm) sieveby the procedure in Practice D346, Section 10 on Preparationof Coke Sample for Laboratory Analysis.8.2 Crush approximately a 30 g of represen
27、tative portion ofthe minus No. 60 sieve analysis sample to pass a No. 200(0.075 mm) sieve. Use a tungsten carbide mill to minimizemetal contamination. Dry this sample to constant weight at 110to 115C (approximately 8 h) and store in a desiccator untilcool. (WarningPreparation of the minus 200 mesh a
28、nalysissamples, from the minus 60 mesh analysis samples, neitherremove metals through loss nor increase metals throughcontamination. Full dissolution of the ash is required.)9. Preparation of Apparatus9.1 Consult the manufacturers instructions for the opera-tion of the atomic absorption spectrophoto
29、meter. The presentmethod assumes that good operating procedures are followed.Design differences between spectrophotometers make it im-practical to specify the required manipulations in detail here.(WarningProper operating procedures are required forsafety as well as for reliability of results. An ex
30、plosion canresult from the flame blow-back unless the correct burner headand operating sequence are used.)10. Procedure10.1 Weigh 10 g (to 0.1 mg) of the dried coke prepared in8.2 into a labeled preignited platinum dish. (WarningInaddition to other precautions, to minimize the potential ofcontaminat
31、ion, prepare the platinum ware by boiling in diluteHCl (5 volume % HCl plus 95 % water) rinsing thoroughlywith a reagent-grade water. After this initial cleaning, handlethe platinum ware with clean tongs, and protect from allsources of contamination. Clean and protect all the glasswareused in analys
32、es.)10.2 Place the platinum dish in a cold muffle furnace andheat directly to 525C with the furnace door opened approxi-mately 7 mm to allow exchange of combustion gases and airuntil all carbonaceous matter is removed. Transfer the platinumdish to a dessicator and cool to room temperature.10.3 To co
33、nvert the ash into a solution, weigh on ananalytical balance onto a tared weighing paper,1g(65 mg,200 6 10C) of Li2B4O7powder. Mix the ash and lithiumtetraborate by sprinkling Li2B4O7evenly over the ash. Placethe platinum dish onto a ceramic triangle resting on a ring standover a Meker type burner a
34、nd adjust the forced air gas flame sothat the Li2B4O7melts in about 30 s. Using the platinum-tippedtongs, gently swirl the melt to dissolve the ash. Continue3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reage
35、nts notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D5056 04 (2010)2heating over the burner for 2 to 3 min or un
36、til a clear,transparent melt is obtained. Alternatively, heat in a furnace at950 6 10C for 10 min or until the Li2B4O7melts.NOTE 4The ideal fusion after cooling will look like a clear glassinside the platinum dish. An opaque melt indicates poor fusion and someof the ash may remain insoluble during t
37、he dissolution step.10.4 Allow the melt to cool for 5 to 10 min on a silica plate.Add a 25.4 mm (1 in.) TFE-fluorocarbon coated magneticstirring bar, and 25 mLof Solution 1, and place immediately onthe stirring hot plate. Heat the solution to just below boilingtemperature and maintain for not more t
38、han 30 min withconstant stirring, until the melt has completely dissolved.NOTE 5If the stirring is not constantly maintained, some of the ashconstituents may precipitate, primarily hydrous silica, due to heating thehighly acidic solution. If this occurs, it is necessary to repeat the analysis.10.5 R
39、emove the dish from the hot plate, rinse down thewalls of the dish with water, and quantitatively transfer thesolution to a 100-mL flask. Add 10 mL of Solution 2, dilutewith water, and mix thoroughly (see Note 5).10.6 Prepare any required dilution using Solution 3 (7.7),diluted 1:1 with water, as th
40、e dilutent.NOTE 6Lanthanum is included in the solution as a releasing agent forcalcium and as an ionization suppressant for aluminum and vanadium.10.7 Establish the AAS operating conditions (see Section9). Select the flame gases and spectral lines from the require-ments presented in Table 2.NOTE 7Ea
41、ch analyst determines the sensitivity and linear range ofcalibration of his own equipment and chooses concentration ranges forstandards compatible with the samples and instrument specific to his ownwork. Sample dilutions can be required for the determination of someelements. Table 2 lists the oxidan
42、t gases used in the analyses fordetermining the precision of this method. However, nitrous oxide can beused as the oxidant for all of the elements of interest to reduce errors dueto chemical interferences.10.8 Prepare calibration standards, including a calibrationblank, using 50 mL of Solution 3 per
43、 100 mL. Dilute withwater (see Note 6).NOTE 8Standard and sample solutions are of similar composition tominimize errors due to matrix effects.10.9 Using the AAS, determine the concentration of eachmetal in the sample solution. Standards must bracket thesample concentration.11. Calculation11.1 Calcul
44、ate parts per million (milligram per kilogram) ofeach metal in the sample as follows:M, ppm mg/kg!5A 3 VW3 C/D (1)where:M = metal,A = metal in solution analyzed, ppm (mg/L),V = volume of sample solution, mL,W = weight of sample, g, andC/D = dilution factor (amount of dilution of the samplesolution i
45、n 10.6 needed to bring the metal concen-trations into the range of standard solutions).11.2 Calculations used and results reported are on a driedoriginal sample basis.12. Report12.1 Report results for each element as parts per million(milligram per kilogram) or mass percent (1000 ppm (mg/kg) = 0.1 %
46、).12.1.1 Use three significant figures if the duplicate valuesdo not vary in the first two figures. Use two significant figureswhen only single values are determined.13. Quality Control (QC)13.1 Confirm the performance of the instrument or the testprocedure by analyzing a QC sample (see 7.9).13.1.1
47、When QC/Quality Assurance (QA) protocols arealready established in the testing facility, these may be usedwhen they confirm the reliability of the test result.13.1.2 When there is no QC/QA protocol established in thetesting facility, Appendix X1 can be used as the QC/QAsystem.14. Precision and Bias1
48、4.1 The values in the following statements were deter-mined in a cooperative program following ASTM RR:D02-1007.4The calibration blank used during this program was notmatrix matched.14.1.1 PrecisionThe precision of this test method asdetermined by the statistical examination of interlaboratory testr
49、esults appears in Table 3.14.1.2 RepeatabilityThe difference between successiveresults obtained by the same operator with the same apparatusunder constant operating conditions on identical test material4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1007.TABLE 2 Experimental ConditionsElement Fuel OxidantWavelength(nm)Aluminum C2H2N2O 309.3Calcium C2H2air 422.7Iron C2H2air 248.3Nickel C2H2air 232.0Silicon C2H2N2O 251.6Sodium C2H2air 589.0Vanadium C2H2N2O 318.3TABLE 3 Repeatability
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