1、Designation: D5056 04 (Reapproved 2010)D5056 15Standard 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, t
2、he 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.1. Scope Scope*1.1 This test method covers the analysis for the commonly determined trace metals (aluminum, calcium, ir
3、on, nickel, silicon,sodium, 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 v
4、alues stated in SI units 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 applicabi
5、lity of regulatorylimitations prior to use. For warning statements, see Sections 8 10.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of Coke Samples for Laboratory AnalysisD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniqu
6、es to Evaluate Analytical Measure-ment System PerformanceD1193 Specification for Reagent Water3. Summary of Test Method3.1 A representative sample of the petroleum coke is ashed at 525C525 C under specified conditions. The ash is fused withlithium tetraborate (Li2B4O7), or lithium metaborate (LiBO3)
7、. The melt is dissolved in dilute hydrochloric acid (HCl), and theresultant solution is analyzed by atomic absorption spectroscopy for the following elements: aluminum, calcium, iron, nickel,silicon, sodium, and vanadium.4. Significance and Use4.1 The presence and concentration of various metallic e
8、lements 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 sample.4.2 The concentration of these elements is one factor in determining the economic value of the coke.
9、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 element concentration and have the least economic value.4.3 The test method provides a standard procedure for
10、 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 interferences can occur when using other than the recommended wavelength for analysis or when usingmulti-ele
11、mental hollow cathode lamps.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved May 1, 2010June 1, 2015. Published May 2010
12、June 2015. Originally approved in 1990. Last previous edition approved in 20042010 asD5056D5056 04 (2010).04. DOI: 10.1520/D5056-04R10.10.1520/D5056-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Sta
13、ndardsvolume 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 version. Becauseit may not be technically possibl
14、e 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 section appears at the end of this standardCopyri
15、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Furnace, electric, capable of regulation of temperature at 525C525 C 6 10C.10 C.6.2 Magnetic Stirring Hot Plate.6.3 Platinum Dish, 5050 mL to 58-mL58 mL capacity.6.4 Platinum D
16、ish, 150150 mL to 200-mL200 mL capacity.6.5 Platinum-Tipped Tongs.6.6 Furnace, electric, capable of regulation of temperature at 950950 C 6 10C10 C or a Meker type forced air burner.6.7 Atomic Absorption Spectrophotometer (AAS), equipped as follows:6.7.1 Background Correction, using either a deuteri
17、um (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 of
18、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 chemicals shall be used in all tests. Unless otherwise indica
19、ted, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society wheresuch specifications are available.3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to perm
20、it 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 (20 mL of concentrated HCl
21、diluted to 100 mL 100 mL with TypeII reagent water).7.4 Lanthanum Additive, Solution 2, 100100 g g/LLlanthanum (dissolve 175 g 175 g LaCl3 in water and dilute to 1 L1 Lwithwater).7.5 Lanthanum Chloride (LaCl3) powder (high purity).7.6 Lithium Tetraborate (Li2B4O7), powder (high purity), or Lithium M
22、etaborate (LiBO3), powder (high purity).7.7 Standard and Sample Dilution Additive, Solution 3Weigh 40.0 g, 40.0 g, to the nearest 0.1 g, 0.1 g, of Li2B4O7 into a150150 mL to 200 mL 200 mL platinum dish, fuse with a Meker type burner to form a liquid, and cool. Alternatively, heat in afurnace at 9509
23、50 C 6 10C10 C for 10 min 10 min or until a liquid forms. Place the cooled platinum dish containing the fusedrecrystallized Li2B4O7, and a magnetic stirring bar into a 2-L2 L beaker. Add 1000 mL 1000 mL of Solution 1 (20 % HCl). Heatand stir the solution on a magnetic stirring hot plate until the me
24、lt completely dissolves. After dissolution, remove the platinumdish with a glass rod. Rinse the platinum dish and glass rod with water into the lithium borate solution. Immediately transfer thewarm solution quantitatively to a 2-L2 L flask. To avoid crystallization add about 100 mL 100 mL of water;
25、stir the solution andcool to room temperature. Add 400 mL 400 mL of Solution 2 (lanthanum additive) and mix. Dilute to 2000 mL 2000 mL withwater, mix thoroughly, and vacuum filter the entire solution through Dow filter paper.3 Reagent Chemicals, American Chemical Society Specifications, American Che
26、mical 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., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Ro
27、ckville, MD.TABLE 1 Applicable Concentration Ranges and Limits ofDetection on a Dried Original Sample BasisElement ConcentrationRange (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 0.2Vanadium 5 to 5
28、00 2.0D5056 152NOTE 2Fifty millilitres of Solution 3 contains 1 g 1 g Li2B4O7, 25 mL 25 mL of Solution 1, 20 % HCl, and 10 mL 10 mL of Solution 2, lanthanumadditive.7.8 Standard Stock SolutionsPrepare standard stock solutions from high purity (99.9 % or better) metals, oxides, or salts.Stock solutio
29、ns of 1000 ppm1000 ppm (mg (mg/L) L) for each metal are needed for preparation of dilute standards in the rangefrom 1.01.0 ppm to 50 ppm 50 ppm (mg/L).Working standards containing aluminum, calcium, iron, nickel, silicon, sodium, andvanadium in concentration ranges below 10 ppm 10 ppm (mg/kg) are to
30、 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 samples can be used to check the validity of the testing process as describedin Section 13.NOT
31、E 3Commercially available standards and other reagent solutions may be used in place 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) (0.250 mm)sieve by the procedure in Practice D346, Se
32、ction 10 on Preparation of Coke Sample for Laboratory Analysis.8.2 Crush approximately a 30 g 30 g of representative portion of the minus No. 60 sieve analysis sample to pass a No. 200(0.075 mm) (0.075 mm) sieve. Use a tungsten carbide mill to minimize metal contamination. Dry this sample to constan
33、t weightat 110110 C to 115C115 C (approximately 8 h) 8 h) and store in a desiccator until cool. (NoteWarningPreparation of theminus 200 mesh analysis samples, from the minus 60 mesh analysis samples, neither remove metals through loss nor increasemetals through contamination. Full dissolution of the
34、 ash is required.) that preparation of the minus 200 mesh analysis samples,from the minus 60 mesh analysis samples, neither remove metals through loss nor increase metals through contamination. Fulldissolution of the ash is required.)9. Preparation of Apparatus9.1 Consult the manufacturers instructi
35、ons for the operation of 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 requ
36、ired for safety as well as 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) 10 g (to 0.1 mg) of the dried coke prepared in 8.28.2into a labeled preignited platinum dish.
37、(WarningIn addition to other precautions, to minimize the potential of contamination, prepare the platinum ware by boiling indilute HCl (5 volume % HCl plus 95 % water) rinsing thoroughly with a reagent-grade water. After this initial cleaning, handlethe platinum ware with clean tongs, and protect f
38、rom all sources of contamination. Clean and protect all the glassware used inanalyses.)10.2 Place the platinum dish in a cold muffle furnace and heat directly to 525C525 C with the furnace door openedapproximately 7 mm 7 mm to allow exchange of combustion gases and air until all carbonaceous matter
39、is removed. Transfer theplatinum dish to a dessicator and cool to room temperature.10.3 To convert the ash into a solution, weigh on an analytical balance onto a tared weighing paper, 1 g (65 mg, 200610C)1 g(65 mg, 200 C 6 10 C) of Li2B4O7 powder. Mix the ash and lithium tetraborate by sprinkling Li
40、2B4O7 evenly over the ash.Place the platinum dish onto a ceramic triangle resting on a ring stand over a Meker type burner and adjust the forced air gas flameso that the Li2B4O7 melts in about 30 s. 30 s. Using the platinum-tipped tongs, gently swirl the melt to dissolve the ash. Continueheating ove
41、r the burner for 22 min to 3 min 3 min or until a clear, transparent melt is obtained. Alternatively, heat in a furnace at950950 C 6 10C10 C for 10 min 10 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 indicat
42、es poor fusion and some of theash may remain insoluble during the dissolution step.10.4 Allow the melt to cool for 55 min to 10 min 10 min on a silica plate. Add a 25.4 mm (1 in.) 25.4 mm (1 in.)TFE-fluorocarbon coated magnetic stirring bar, and 25 mL 25 mL of Solution 1, and place immediately on th
43、e stirring hot plate.Heat the solution to just below boiling temperature and maintain for not more than 30 min 30 min with constant stirring, until themelt has completely dissolved.NOTE 5If the stirring is not constantly maintained, some of the ash constituents may precipitate, primarily hydrous sil
44、ica, 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 water, and quantitatively transfer the solutionto a 100-mL100 mL flask. Add 10 mL 10 mL of Solution 2, dilute with wate
45、r, 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 agent for calcium and as an ionization suppressant for aluminum and vanadium.D5056 15310.7 Establish the AA
46、S 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 of his own equipment and chooses concentration ranges for standardscompatible with the samples and
47、 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 method. However, nitrous oxide can be used as the oxidant for all ofthe elements of interest to red
48、uce errors due to chemical interferences.10.8 Prepare calibration standards, including a calibration blank, using 50 mL 50 mL of Solution 3 per 100 mL. 100 mL. Dilutewith water (see Note 6).NOTE 8Standard and sample solutions are of similar composition to minimize errors due to matrix effects.10.9 U
49、sing the AAS, determine the concentration of each metal in the sample solution. Standards must bracket the sampleconcentration.11. Calculation11.1 Calculate parts per million (milligram per kilogram) of each metal in the sample as follows:M,ppm mg/kg!5A 3VW 3C/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 sample solution in 10.6 needed to bring the metal concentrations into the rangeof standard solutions).1
