1、Designation: D5056 15D5056 17Standard 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 of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the analysis for the commonly determined trace metals (aluminum, calcium, iron, nickel, silicon,sodi
3、um, and vanadium) in laboratory analysis samples of raw and calcined petroleum coke by atomic absorption spectroscopy.1.2 The elemental concentration ranges for which this test method is applicable and the limits of detection of this test methodare listed in Table 1.1.3 The values stated in SI units
4、 are to be regarded as the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimita
5、tions prior to use. For warning statements, see Sections 8 10.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations
6、issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of Coke Samples for Laboratory AnalysisD1193 Specification for Reagent WaterD6299 Practice for Applying Statistical Quality Assura
7、nce and Control Charting Techniques to Evaluate Analytical Measure-ment System Performance1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition
8、approved June 1, 2015May 1, 2017. Published June 2015May 2017. Originally approved in 1990. Last previous edition approved in 20102015 asD5056 04 (2010).D5056 15. DOI: 10.1520/D5056-15.10.1520/D5056-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Servi
9、ce at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous
10、 version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes
11、 section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D1193D7740 Specification for Reagent WaterPractice for Optimization, Calibration, and Validation of Atomic AbsorptionSpectrometry for Metal An
12、alysis of Petroleum Products and Lubricants3. Summary of Test Method3.1 A representative sample of the petroleum coke is ashed at 525 C under specified conditions. The ash is fused with lithiumtetraborate (Li2B4O7), or lithium metaborate (LiBO3). The melt is dissolved in dilute hydrochloric acid (HC
13、l), and the resultantsolution is analyzed by atomic absorption spectroscopy for the following elements: aluminum, calcium, iron, nickel, silicon,sodium, and vanadium.3.2 Standard practice for using atomic absorption spectrometry for determination of metals in petroleum products and lubricantscan be
14、found in Practice D7740.4. Significance and Use4.1 The presence and concentration of various metallic elements in a petroleum coke are major factors in the suitability of thecoke for various uses. This test method provides a means of measuring the amounts of those metallic elements in the coke sampl
15、e.4.2 The concentration of these elements is one factor in determining the economic value of the coke. Coke used for productionof electrodes will have different specification requirements dependent on what service the electrodes will be used in. Generally thefuel cokes are highest in metallic elemen
16、t concentration and have the least economic value.4.3 The test method provides a standard procedure for use by the purchaser and seller in the commercial transfer of petroleumcoke to determine whether the lot of coke meets the specifications of the purchasing party.5. Interferences5.1 Spectral inter
17、ferences can occur when using other than the recommended wavelength for analysis or when usingmulti-elemental hollow cathode lamps.6. Apparatus6.1 Furnace, electric, capable of regulation of temperature at 525 C 6 10 C.6.2 Magnetic Stirring Hot Plate.6.3 Platinum Dish, 50 mL to 58 mL capacity.6.4 Pl
18、atinum Dish, 150 mL to 200 mL capacity.6.5 Platinum-Tipped Tongs.6.6 Furnace, electric, capable of regulation of temperature at 950 C 6 10 C or a Meker type Meker-type forced air burner.6.7 Atomic Absorption Spectrophotometer (AAS), equipped as follows:6.7.1 Background Correction, using either a deu
19、terium (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-slot, capable of supporting an air-acetylene flame.6.7.4 Hollow Cathode Lamps, one for each
20、 of the elements to be analyzed: aluminum, calcium, iron, nickel, silicon, sodium,and vanadium.NOTE 1Multi-elemental lamps can also be used; however, spectral interferences are possible (see 5.1).7. Reagents7.1 Purity of ReagentsReagent grade Reagent-grade chemicals shall be used in all tests. Unles
21、s otherwise indicated, it isintended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American ChemicalTABLE 1 Applicable Concentration Ranges and Limits ofDetection on a Dried Original Sample BasisElement ConcentrationRange (mg/kg) LimitDetection
22、(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 0.2Vanadium 5 to 500 2.0D5056 172Society where such specifications are available.3 Other grades may be used, provided it is first ascertained that the reagent is ofsufficientl
23、y high purity to permit its use without lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as defined byType II of Specification D1193.7.3 Hydrochloric Acid, Solution 1, 20 % by volume (20 mL of con
24、centrated HCl diluted to 100 mL with Type II reagent water).7.4 Lanthanum Additive, Solution 2, 100 gL lanthanum (dissolve 175 g LaCl3 in water and dilute to 1 L with water).7.5 Lanthanum Chloride (LaCl3) powder (high purity).7.6 Lithium Tetraborate (Li2B4O7), powder (high purity), or Lithium Metabo
25、rate (LiBO3), powder (high purity).7.7 Standard and Sample Dilution Additive, Solution 3Weigh 40.0 g, to the nearest 0.1 g, of Li2B4O7 into a 150 mLto 200 mLplatinum dish, fuse with a Meker type Meker-type burner to form a liquid, and cool. Alternatively, heat in a furnace at 950 C 610 C for 10 min
26、or until a liquid forms. Place the cooled platinum dish containing the fused recrystallized Li2B4O7, and a magneticstirring bar into a 2 L beaker. Add 1000 mL of Solution 1 (20 % HCl). Heat and stir the solution on a magnetic stirring hot plateuntil the melt completely dissolves.After dissolution, r
27、emove the platinum dish with a glass rod. Rinse the platinum dish and glassrod with water into the lithium borate solution. Immediately transfer the warm solution quantitatively to a 2 L flask. To avoidcrystallization add about 100 mL of water; stir the solution and cool to room temperature. Add 400
28、 mL of Solution 2 (lanthanumadditive) and mix. Dilute to 2000 mL with water, mix thoroughly, and vacuum filter the entire solution through Dow filter paper.NOTE 2Fifty millilitres of Solution 3 contains 1 g Li2B4O7, 25 mL of Solution 1, 20 % HCl, and 10 mL of Solution 2, lanthanum additive.7.8 Stand
29、ard Stock SolutionsPrepare standard stock solutions from high purity (99.9 % or better) metals, oxides, or salts.Stock solutions of 1000 ppm (mgL) for each metal are needed for preparation of dilute standards in the range from 1.0 ppm to50 ppm (mg/L). Working standards containing aluminum, calcium,
30、iron, nickel, silicon, sodium, and vanadium in concentrationranges below 10 ppm (mg/kg) are to be prepared daily to ensure stability.7.9 Quality Control (QC) Samples, preferably are portions of one or more petroleum coke samples that are stable andrepresentative of the samples of interest. These QC
31、samples can be used to check the validity of the testing process as describedin Section 13.7.9.1 NIST SRM 2718Agreen petroleum coke or 2719 calcined petroleum coke can be used as a QC material for this analysis.4NOTE 3Commercially available standards and other reagent solutions may be used in place
32、of laboratory preparations.8. Sample Preparation8.1 Crush and divide the initial sample to obtain a laboratory analysis sample. Crush to pass a No. 60 (0.250 mm) sieve by theprocedure in Practice D346, Section 10 on Preparation of Coke Sample for Laboratory Analysis.8.2 Crush approximately a 30 g of
33、 representative portion of the minus No. 60 sieve analysis sample to pass a No. 200(0.075 mm) sieve. Use a tungsten carbide mill to minimize metal contamination. Dry this sample to constant weight at 110 C to115 C (approximately 8 h) and store in a desiccator until cool. (Note that preparation of th
34、e minus 200 mesh analysis samples,from the minus 60 mesh analysis samples, neither removeremoves metals through loss nor increaseincreases metals throughcontamination. Full dissolution of the ash is required.)9. Preparation of Apparatus9.1 Consult the manufacturers instructions for the operation of
35、the atomic absorption spectrophotometer. The present methodassumes that good operating procedures are followed. Design differences between spectrophotometers make it impractical tospecify the required manipulations in detail here. (WarningProper operating procedures are required for safety as well a
36、s forreliability of results. An explosion can result from the flame blow-back unless the correct burner head and operating sequence areused.)10. Procedure10.1 Weigh 10 g (to 0.1 mg) of the dried coke prepared in 8.2 into a labeled preignited platinum dish. (WarningIn additionto other precautions, to
37、 minimize the potential of contamination, prepare the platinum ware by boiling in dilute HCl (5 volume% HCl plus 95 % water) rinsing thoroughly with a reagent-grade water. After this initial cleaning, handle the platinum ware withclean tongs, and protect from all sources of contamination. Clean and
38、protect all the glassware used in analyses.)10.2 Place the platinum dish in a cold muffle furnace and heat directly to 525 C with the furnace door opened approximately7 mm to allow exchange of combustion gases and air until all carbonaceous matter is removed. Transfer the platinum dish to adessicato
39、r and cool to room temperature.3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K.
40、, and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.4 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 2300, Gaithersburg, MD 20899-2300, http:/www.nist.gov.D5056 17310.3 To convert the ash in
41、to a solution, weigh on an analytical balance onto a tared weighing paper, 1 g (65 mg, 200 C 610 C) of Li2B4O7 powder. Mix the ash and lithium tetraborate by sprinkling Li2B4O7 evenly over the ash. Place the platinum dishonto a ceramic triangle resting on a ring stand over a Meker type Meker-type bu
42、rner and adjust the forced air gas flame so thatthe Li2B4O7 melts in about 30 s. Using the platinum-tipped tongs, gently swirl the melt to dissolve the ash. Continue heating overthe burner for 2 min to 3 min or until a clear, transparent melt is obtained. Alternatively, heat in a furnace at 950 C 6
43、10 C for10 min or until the Li2B4O7 melts.NOTE 4The ideal fusion after cooling will look like a clear glass inside the platinum dish. An opaque melt indicates poor fusion and some of theash may remain insoluble during the dissolution step.10.4 Allow the melt to cool for 5 min to 10 min on a silica p
44、late. Add a 25.4 mm (1 in.) TFE-fluorocarbon coated magneticstirring bar, and 25 mL of Solution 1, and place immediately on the stirring hot plate. Heat the solution to just below boilingtemperature and maintain for not more than 30 min with constant stirring, until the melt has completely dissolved
45、.NOTE 5If the stirring is not constantly maintained, some of the ash constituents may precipitate, primarily hydrous silica, due to heating the highlyacidic solution. If this occurs, it is necessary to repeat the analysis.10.5 Remove the dish from the hot plate, rinse down the walls of the dish with
46、 water, and quantitatively transfer the solutionto a 100 mL flask. Add 10 mL of Solution 2, dilute with water, and mix thoroughly (see Note 5).10.6 Prepare any required dilution using Solution 3 (7.7), diluted 1:1 with water, as the dilutent.NOTE 6Lanthanum is included in the solution as a releasing
47、 agent for calcium and as an ionization suppressant for aluminum and vanadium.10.7 Establish the AAS operating conditions (see Section 9). Select the flame gases and spectral lines from the requirementspresented in Table 2.NOTE 7Each analyst determines the sensitivity and linear range of calibration
48、 of his own equipment and chooses concentration ranges for standardscompatible with the samples and instrument specific to his own work. Sample dilutions can be required for the determination of some elements. Table2 lists the oxidant gases used in the analyses for determining the precision of this
49、method. However, nitrous oxide can be used as the oxidant for all ofthe elements of interest to reduce errors due to chemical interferences.10.8 Prepare calibration standards, including a calibration blank, using 50 mL of Solution 3 per 100 mL. Dilute with water (seeNote 6).NOTE 8Standard and sample solutions are of similar composition to minimize errors due to matrix effects.10.9 Using the AAS, determine the concentration of each metal in the sample solution. Standards must bracket the sampleconcentration.11. Calculation11.1 Calculate parts p
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