1、Designation: D6414 14Standard Test Methods forTotal Mercury in Coal and Coal Combustion Residues byAcid Extraction or Wet Oxidation/Cold Vapor AtomicAbsorption1This standard is issued under the fixed designation D6414; the number immediately following the designation indicates the year oforiginal ad
2、option 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.1. Scope1.1 These test methods cover procedures to determine thetotal mercury cont
3、ent in a sample of coal or coal combustionresidue.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 Warning: Mercury has been designated by many regu-latory agencies as a hazardous material that can cause seriousmedical is
4、sues. Mercury, or its vapor, has been demonstrated tobe hazardous to health and corrosive to materials. Cautionshould be taken when handling mercury and mercury contain-ing products. See the applicable product Safety Data Sheet(SDS) for additional information. Users should be aware thatselling mercu
5、ry and/or mercury containing products into yourstate or country may be prohibited by law.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 practice
6、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD1193 Specification for Reagent WaterD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sample ofCoa
7、l and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD7582 Test Methods for Proximate Analysis of Coal andCoke by Macro Thermogravimetric AnalysisE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodIEEE/ASTM S
8、I 10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System2.2 ISO Standard3ISO 5725-6:1994 Accuracy of measurement methods andresults-Part 63. Terminology3.1 For definitions of terms used in this standard, refer toTerminology D121.4. Summary of Test Method4.1 Test Metho
9、d AMercury in the analysis sample issolubilized by heating the test sample at a specified tempera-ture in a mixture of nitric and hydrochloric acids. The acidsolutions produced are transferred into a vessel in which themercury is reduced to elemental mercury. The mercury vapor isdetermined by flamel
10、ess cold-vapor atomic absorption spec-troscopy.4.2 Test Method BMercury in the analysis sample issolubilized by heating the test sample in a mixture of nitric andsulfuric acids with vanadium pentoxide.4The acid solutionsproduced are transferred into a vessel in which the mercury isreduced to element
11、al mercury. The mercury vapor is deter-mined by flameless cold-vapor atomic absorption spectros-copy.NOTE 1Mercury and mercury salts can be volatilized at low tempera-tures. Precautions against inadvertent mercury loss should be taken whenusing this method.5. Significance and Use5.1 The emission of
12、mercury during coal combustion can bean environmental concern.1These test methods are under the jurisdiction ofASTM Committee D05 on Coaland Coke and are the direct responsibility of Subcommittee D05.29 on MajorElements in Ash and Trace Elements of Coal.Current edition approved March 1, 2014. Publis
13、hed March 2014. Originallyapproved in 1999. Last previous edition approved in 2006 as D6414 - 01(2006).DOI: 10.1520/D6414-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
14、refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland.4Crock, J. G., Open-File Report, U.S. Geological Survey, 8784, p.19.Copyright ASTM International, 100
15、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 When representative test portions are analyzed accord-ing to one of these procedures, the total mercury is represen-tative of concentrations in the sample.6. Apparatus6.1 Apparatus for Test Method A:6.1.1 Analytical
16、 Balance, with a sensitivity of 0.1 mg.6.1.2 Atomic Absorption Spectrophotometer, with a flame-less cold-vapor mercury analysis system.6.1.3 Digestion Vessels, 100- to 250-mL bottles with anO-ring seal and screw cap. Bottle must be compatible for usewith aqua regia. Polycarbonate and HDPE are accept
17、able.Bottles and cap assemblies shall be washed in 1-to-1 HCl thendried before each use.NOTE 2Other bottle and cap assemblies may be used provided theyare compatible for use with aqua regia at a temperature of 80C.6.1.4 Heat Source, a water bath capable of maintaining atemperature of 80C.6.1.5 Syrin
18、ge and Filter, a 20-cm3syringe and a 1-m PTFEfilter to fit syringe.6.2 Apparatus for Test Method B:6.2.1 Analytical Balance, with a sensitivity of 0.1 mg.6.2.2 Atomic Absorption Spectrophotometer, with a flame-less cold-vapor mercury analysis system.6.2.3 Digestion Vessels, 16- by 150-mm disposable
19、glasstest tubes.6.2.4 Heat Source, an aluminum block with 18-mm holes toaccommodate the disposable test tubes. The block shall becapable of slowly reaching and maintaining a final temperatureof 150C. The block can be heated by placing it on a hot plateor it can contain its own internal heating eleme
20、nts.7. Sample7.1 Prepare the analysis sample in accordance with PracticeD2013 by pulverizing the material to pass a 250-m (No. 60)sieve.7.2 Analyze separate test portions for moisture content inaccordance with Test Method D3173 or Test Method D7582.Test Method A for the Analysis of Mercury by Using
21、AcidExtraction8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused. Unless otherwise indicated, it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.5Other g
22、rades can be usedprovided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of AcidsUse trace metal purity grade acids orequivalent. Redistilled acids are acceptable.8.3 Purity of WaterUse water equi
23、valent toASTM Type IIreagent water of Specification D1193.8.4 Mercury Standard Stock Solution 1000 ppm (1000g/mL)Dissolve 1.0800 g of mercury (II) oxide (HgO) in aminimum volume of HCl (1+1) and dilute to 1 L with water.Alternatively, use a commercially available stock solutionspecifically prepared
24、for atomic absorption spectrometry.8.5 Mercury Standard Solution (100 ng/mL)Prepare themercury standard solution fresh daily. Dilute 5 mL of themercury standard stock solution to 500 mL with deionizedwater. Further dilute 10 mL of this intermediate solution to 1 Lwith deionized water.8.6 Nitric Acid
25、Concentrated (HNO3, sp. gr. 1.42).8.7 Hydrochloric AcidConcentrated (HCl, sp. gr. 1.19).8.8 Sodium Chloride/Hydroxylamine Sulfate SolutionDissolve 12 g 6 0.01 g of sodium chloride and 12 g 6 0.01 gof hydroxylamine sulfate in water and dilute to 100 mL.8.9 Potassium Permanganate Solution (5 g/100 mL)
26、Dissolve5gofpotassium permanganate (KMnO4) in waterand dilute to 100 mL.8.10 Stannous Chloride Solution (100 g/L)Dissolve 100 gof stannous chloride dihydrate (SnCl22 H2O) in 300 mL ofconcentrated hydrochloric acid (HCl, sp. gr. 1.19) and CAU-TIOUSLY dilute to 1 L with water. This solution is stable
27、forapproximately one week if refrigerated.8.11 Certified Reference Material (CRM)Use CertifiedReference Material (CRM) coals with dry-basis mercury val-ues for which confidence limits are issued by a recognizedcertifying agency such as the National Institute of Standardsand Technology (NIST). It is
28、recommended that the user verifythe value with the certifying agency before using the CRM coalfor quality control purposes.9. Procedure9.1 Preparation of Test Solution A (Extraction Step):9.1.1 Weigh a test portion of approximately1gofthesample into a digestion bottle. Record the weight (Ws)tothenea
29、rest 0.0001 g.9.1.2 Quantitatively add 2 mL of concentrated nitric acidand 6 mL of concentrated hydrochloric acid to the digestionbottle and secure the cap.9.1.3 Transfer the digestion bottle and contents to a waterbath that has been heated to 80C and heat for 1 h. Secure thedigestion bottle in such
30、 a way as to keep the contents below thesurface of the water.9.1.4 After 1 h, remove the digestion bottle and allow tocool to room temperature.NOTE 3Caution: Carefully relieve the pressure by slowly removingthe cap.9.1.5 Add 36.5 mL of water and mix the contents.9.1.6 Add 5 mL of 5 % potassium perma
31、nganate solution.Allow the mixture to stand for 10 min.5Reagent 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.
32、, Poole, Dorset, U.K., and the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D6414 1429.1.7 Add 0.5 mL of the hydroxylamine sodium chloridesolution and mix. If a pink color persists for more than 1 min,add an additional 0.5 mL of the hydr
33、oxylamine sodiumchloride solution and mix. Note the total volume and recordthis volume (V) for use in the final calculations.9.2 Preparation of Reagent BlankPrepare a reagent blankby repeating the procedure in 9.1 but without the test portion ofthe sample.9.3 Preparation of Control Sample:9.3.1 Prep
34、are a test portion of a CRM coal for analysis usingthe procedure described in 9.1. Record the expected value ofmercury, the certified value in the coal, as CRME.9.3.2 Alternatively, weigh a test portion of1gofaCRM.After the addition of the nitric and hydrochloric acids to thedigestion bottle, add me
35、rcury standard solution (8.5). Thevolume of mercury standard solution to be added should yieldan amount of mercury approximately equivalent to that in theCRM coal (Note 4).9.3.3 Calculate the expected value of mercury CRME asfollowsCRME 5 Wcrm*CRM1Vstandard*0.1!/Wcrm (1)where:Wcrm = dry weight of th
36、e CRM coal used for prepara-tion of the quality control sample, g;CRM = certified value of mercury in the quality controlsample;Vstandard = volume of mercury standard solution added tothe digestion bottle, mL; and0.1 = the concentration of the mercury standardsolution, g/mL.NOTE 4Atest portion of 0.
37、9-g dry weight of a CRM coal with 0.11 g/g(110 ng/g) of mercury is weighed out as a quality control sample. To yieldan amount approximately equivalent to that present in the CRM coal, 0.9mL of the mercury standard solution is added to the digestion bottle afterthe addition of the nitric and hydrochl
38、oric acids. CRME calculates to 0.21g/g.9.4 Atomic Absorption Analyses:9.4.1 Instrument ConditionsFollow the instrument manu-facturers recommended procedure to align the optical cell inthe beam path of the atomic absorption spectrophotometer andoptimize the performance of the instrument and the flame
39、lesscold-vapor apparatus.9.4.2 Instrument Calibration:9.4.2.1 Prepare 50 mL of 0.5, 1, 3, 5, and 10 ng/mL (ppb) ofmercury calibration standards in a solution of 10 % HCl byserial dilution of the mercury standard solution.9.4.2.2 Add a specified volume (Vcal) of a calibrationsolution to the reduction
40、 flask or reduction system.NOTE 5If an autosampler equipped with a peristaltic pump is used fordelivery of both calibration and analyses sample solutions to the reductionsystem, a specific volume is not required.9.4.2.3 Either manually or by means of an autosamplingdevice begin the analyses of the c
41、alibration solution by addingenough stannous chloride solution so as to ensure completereduction of the mercury in the calibration solution.9.4.2.4 Record the absorbance of the calibration standard.Repeat for each calibration standard.9.4.3 Analysis of Test Solution A:9.4.3.1 Using the 20-cm3syringe
42、, draw Test Solution A intothe syringe.9.4.3.2 Fit the syringe with a 1-m filter.9.4.3.3 Filter a volume equivalent to Vcal of Test SolutionAinto the reduction flask or reduction system.NOTE 6Alaboratory centrifuge may also be used to separate the solidsfrom the test solution.9.4.3.4 Determine the a
43、bsorbance (As ) of the Test SolutionA using the procedure described in 9.4.2.9.4.3.5 Using 10 % HCl, dilute test solutions with mercuryabsorbances greater than the highest calibration standard togive an estimated absorbance equivalent to the 3-ng/mLcalibration standard and reanalyze.9.4.3.6 Record t
44、he dilution factor as DF.9.4.4 Analysis of the Reagent BlankDetermine the absor-bance (Ab) of the reagent blank using the procedure describedin 9.4.3.9.4.5 Analysis of the Quality Control SampleDeterminethe absorbance (Aqs) of the quality control sample using theprocedure described in 9.4.3.Test Met
45、hod B for the Analysis of Mercury by Using WetOxidation Extraction10. Reagents10.1 Purity of ReagentsReagent grade chemicals shall beused. Unless otherwise indicated, it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American Chemical S
46、ociety wheresuch specifications are available.5Other grades can be usedprovided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.10.2 Purity of AcidsUse trace metal purity grade acids orequivalent. Redistilled
47、 acids are acceptable.10.3 Purity of WaterUse water equivalent to ASTM TypeII reagent water of Specification D1193.10.4 Mercury Standard Stock Solution 1000 ppm (1000g/mL)Dissolve 1.0800 g of mercury (II) oxide (HgO) in aminimum volume of HCl (1+1) and dilute to 1 L with water.Alternatively, use a c
48、ommercially available stock solutionspecifically prepared for atomic absorption spectrometry.10.5 Mercury Standard Solution (100 ng/mL)Prepare themercury standard solution fresh daily. Dilute 5 mL of themercury standard stock solution to 500 mL with deionizedwater. Further dilute 10 mL of this inter
49、mediate solution to 1 Lwith deionized water.10.6 Nitric AcidConcentrated (HNO3, sp. gr. 1.42).10.7 Hydrochloric AcidConcentrated (HCl, sp. gr. 1.19).10.8 Sulfuric AcidH2SO4, sp. gr. 1.83).10.9 Vanadium Pentoxide, V2O5Remove traces of mer-cury by roasting the V2O5in a fume hood at a temperaturebelow 690C, the melting point of V2O5, in a porcelain dishusing a muffle furnace or a Fisher burner.D6414 143NOTE 7Warning: V2O5is highly toxic, an irritant, and a possiblemutagen.10.10 Stannous Chloride Solution (100 g/L)Dissolve 100g of st
