1、Designation: D 6414 01 (Reapproved 2006)Standard 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 D 6414; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover procedures to determine
3、thetotal mercury content in a sample of coal or coal combustionresidue.1.2 The values stated in SI units are regarded as thestandard.1.3 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 estab
4、lish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 121 Terminology of Coal and CokeD 1193 Specification for Reagent WaterD 2013 Practice for Preparing Coal Samples for AnalysisD 3173 Test
5、Method for Moisture in theAnalysis Sample ofCoal and CokeD 3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD 5142 Test Methods for Proximate Analysis of the Analy-sis Sample of Coal and Coke by Instrumental ProceduresIEEE/ASTM SI 10 Standard for Use of the In
6、ternationalSystem of Units (SI): The Modern Metric SystemE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard3ISO 5725-6:1994 Accuracy of measurement methods andresults-Part 63. Terminology3.1 For definitions of terms used in this standard
7、, refer toTerminology D 121.4. Summary of Test Method4.1 Test Method 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 red
8、uced to elemental mercury. The mercury vapor isdetermined by flameless 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
9、transferred into a vessel in which the mercury isreduced to elemental 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 take
10、n whenusing this method.5. Significance and Use5.1 The emission of mercury during coal combustion can bean environmental concern.5.2 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. Apparatus
11、6.1 Apparatus for Test Method A:6.1.1 Analytical 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 use1T
12、hese 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 April 1, 2006. Published April 2006. Originallyapproved in 1999. Last previous editio
13、n approved in 2001 as D 6414 - 01.2For 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 Summary page onthe ASTM website.3Available from Internation
14、al 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.19.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.with aqua
15、 regia. Polycarbonate and HDPE are acceptable.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 ma
16、intaining atemperature of 80C.6.1.5 Syringe 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 Dig
17、estion Vessels, 16- by 150-mm disposable 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 c
18、an contain its own internal heating elements.7. Sample7.1 Prepare the analysis sample in accordance with MethodD 2013 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 D 3173 or Test Methods D 5142.Test Met
19、hod A for the Analysis of Mercury by Using 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 wher
20、esuch 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.8.2 Purity of AcidsUse trace metal purity grade acids orequivalent. Redistilled acids are a
21、cceptable.8.3 Purity of WaterUse water equivalent toASTM Type IIreagent water of Specification D 1193.8.4 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 av
22、ailable stock solutionspecifically prepared 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 solutio
23、n to 1 Lwith deionized water.8.6 Nitric AcidConcentrated (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
24、Potassium Permanganate Solution (5 g/100 mL)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
25、 to 1 L with water. This solution is stable 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 Institu
26、te of Standardsand Technology (NIST). It is 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 dige
27、stion bottle. Record the weight (Ws)tothenearest 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
28、 for 1 h. Secure thedigestion bottle in such 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 co
29、ntents.9.1.6 Add 5 mL of 5 % potassium permanganate solution.Allow the mixture to stand for 10 min.9.1.7 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 hydroxylamine sodiumchloride solution and mix. Note t
30、he 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 Prepare a test portion of a CRM coal for analysis usi
31、ngthe 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 mercury standard solution (8.5). The5Reagent Chemic
32、als, 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 Pharmacopeia andNational
33、Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D 6414 01 (2006)2volume 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*CRM
34、1 Vstandard*0.1!/Wcrm (1)where:Wcrm = dry weight of the CRM coal used for prepa-ration of the quality control sample, g;CRM = certified value of mercury in the quality con-trol sample;Vstandard = volume of mercury standard solution added tothe digestion bottle, mL; and0.1 = the concentration of the
35、mercury standardsolution, g/mL.NOTE 4A test portion of 0.9-g dry weight of a CRM coal with 0.11g/g (110 ng/g) of mercury is weighed out as a quality control sample. Toyield an amount approximately equivalent to that present in the CRM coal,0.9 mL of the mercury standard solution is added to the dige
36、stion bottleafter the addition of the nitric and hydrochloric acids. CRME calculates to0.21 g/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 an
37、doptimize the performance of the instrument and the flamelesscold-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 specifie
38、d volume (Vcal) of a calibrationsolution to the reduction 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 m
39、eans of an autosamplingdevice begin the analyses of the calibration 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 An
40、alysis of Test Solution A:9.4.3.1 Using the 20-cm3syringe, 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 6A laboratory centrifuge may also be used to separat
41、e thesolids from the test solution.9.4.3.4 Determine the absorbance (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
42、-ng/mLcalibration standard and reanalyze.9.4.3.6 Record the 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 cont
43、rol sample using theprocedure described in 9.4.3.Test Method 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 C
44、ommittee onAnalytical Reagents of the American Chemical Society 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
45、 trace metal purity grade acids orequivalent. Redistilled acids are acceptable.10.3 Purity of WaterUse water equivalent to ASTM TypeII reagent water of Specification D 1193.10.4 Mercury Standard Stock Solution 1000 ppm (1000g/mL)Dissolve 1.0800 g of mercury (II) oxide (HgO) in aminimum volume of HCl
46、 (1+1) and dilute to 1 L with water.Alternatively, use a commercially 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
47、mL with deionizedwater. Further dilute 10 mL of this intermediate 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
48、 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.NOTE 7Warning: V2O5is highly toxic, an irritant, and a possiblemutagen.10.10 Stannous Chloride Solution (100 g/L)Dissolve 100g of stannous chloride
49、dihydrate (SnCl22H2O) in 300 mL ofconcentrated hydrochloric acid (HCl, sp. gr. 1.19) and CAU-TIOUSLY dilute to 1 L with water. This solution is stable forapproximately one week if refrigerated.10.11 Sodium Dichromate, 25 % (w/v) SolutionDissolve25gofNa2Cr2O72H2O in water and dilute to 100 mL.10.12 Complex Reducing SolutionDissolve 30 g of hy-droxylamine hydrochloride and 30 g of sodium chloride (NaCl)in approximately 500 mL of water. Slowly add 100 mL ofconcentrated sulfuric acid. Allow the solution to cool, thendilute to 1 L wi
