Standard Test Methods for Total Mercury in Coal and Coal Combustion Residues by Acid Extraction or Wet Oxidation/Cold Vapor Atomic Absorption

SIGNIFICANCE AND USE
The emission of mercury during coal combustion can be an environmental concern.
When representative test portions are analyzed according to one of these procedures, the total mercury is representative of concentrations in the sample.
SCOPE
1.1 These test methods cover procedures to determine the total mercury content in a sample of coal or coal combustion residue.
1.2 The values stated in SI units are regarded as the standard.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Historical
Publication Date
31-Mar-2006
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ASTM D6414-01(2006) - Standard Test Methods for Total Mercury in Coal and Coal Combustion Residues by Acid Extraction or Wet Oxidation/Cold Vapor Atomic Absorption
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6414 − 01(Reapproved 2006)
Standard Test Methods for
Total Mercury in Coal and Coal Combustion Residues by
Acid Extraction or Wet Oxidation/Cold Vapor Atomic
Absorption
This standard is issued under the fixed designation D6414; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ISO Standard
ISO 5725-6:1994 Accuracy of measurement methods and
1.1 These test methods cover procedures to determine the
results-Part 6
total mercury content in a sample of coal or coal combustion
residue.
3. Terminology
1.2 The values stated in SI units are regarded as the
3.1 For definitions of terms used in this standard, refer to
standard.
Terminology D121.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 Test Method A—Mercury in the analysis sample is
priate safety and health practices and determine the applica-
solubilized by heating the test sample at a specified tempera-
bility of regulatory limitations prior to use.
ture in a mixture of nitric and hydrochloric acids. The acid
solutions produced are transferred into a vessel in which the
2. Referenced Documents mercuryisreducedtoelementalmercury.Themercuryvaporis
determined by flameless cold-vapor atomic absorption spec-
2.1 ASTM Standards:
troscopy.
D121 Terminology of Coal and Coke
4.2 Test Method B—Mercury in the analysis sample is
D1193 Specification for Reagent Water
D2013 Practice for Preparing Coal Samples for Analysis solubilized by heating the test sample in a mixture of nitric and
sulfuric acids with vanadium pentoxide. The acid solutions
D3173 Test Method for Moisture in the Analysis Sample of
Coal and Coke produced are transferred into a vessel in which the mercury is
reduced to elemental mercury. The mercury vapor is deter-
D3180 Practice for Calculating Coal and Coke Analyses
from As-Determined to Different Bases mined by flameless cold-vapor atomic absorption spectros-
copy.
D5142 Test Methods for ProximateAnalysis of theAnalysis
NOTE 1—Mercury and mercury salts can be volatilized at low tempera-
Sample of Coal and Coke by Instrumental Procedures
tures. Precautions against inadvertent mercury loss should be taken when
(Withdrawn 2010)
using this method.
IEEE/ASTM SI 10 Standard for Use of the International
System of Units (SI): The Modern Metric System
5. Significance and Use
E691 Practice for Conducting an Interlaboratory Study to
5.1 The emission of mercury during coal combustion can be
Determine the Precision of a Test Method
an environmental concern.
5.2 When representative test portions are analyzed accord-
ing to one of these procedures, the total mercury is represen-
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD05onCoal
tative of concentrations in the sample.
and Coke and are the direct responsibility of Subcommittee D05.29 on Major
Elements in Ash and Trace Elements of Coal.
6. Apparatus
Current edition approved April 1, 2006. Published April 2006. Originally
approved in 1999. Last previous edition approved in 2001 as D6414 - 01. DOI:
6.1 Apparatus for Test Method A:
10.1520/D6414-01R06.
6.1.1 Analytical Balance, with a sensitivity of 0.1 mg.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Available from International Organization for Standardization (ISO), 1 rue de
The last approved version of this historical standard is referenced on Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland.
www.astm.org. Crock, J. G., Open-File Report, U.S. Geological Survey, 87–84, p.19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6414 − 01 (2006)
6.1.2 Atomic Absorption Spectrophotometer, with a flame- Alternatively, use a commercially available stock solution
less cold-vapor mercury analysis system. specifically prepared for atomic absorption spectrometry.
6.1.3 Digestion Vessels, 100- to 250-mL bottles with an
8.5 Mercury Standard Solution (100 ng/mL)—Prepare the
O-ring seal and screw cap. Bottle must be compatible for use
mercury standard solution fresh daily. Dilute 5 mL of the
with aqua regia. Polycarbonate and HDPE are acceptable.
mercury standard stock solution to 500 mL with deionized
Bottles and cap assemblies shall be washed in 1-to-1 HCl then
water. Further dilute 10 mLof this intermediate solution to 1 L
dried before each use.
with deionized water.
NOTE 2—Other bottle and cap assemblies may be used provided they
8.6 Nitric Acid—Concentrated (HNO , sp. gr. 1.42).
are compatible for use with aqua regia at a temperature of 80°C.
8.7 Hydrochloric Acid—Concentrated (HCl, sp. gr. 1.19).
6.1.4 Heat Source, a water bath capable of maintaining a
8.8 Sodium Chloride/Hydroxylamine Sulfate Solution—
temperature of 80°C.
Dissolve 12 g 6 0.01 g of sodium chloride and 12 g 6 0.01 g
6.1.5 Syringe and Filter,a20-cm syringeanda1-µmPTFE
of hydroxylamine sulfate in water and dilute to 100 mL.
filter to fit syringe.
8.9 Potassium Permanganate Solution (5 g/100 mL)—
6.2 Apparatus for Test Method B:
Dissolve5gof potassium permanganate (KMnO ) in water
6.2.1 Analytical Balance, with a sensitivity of 0.1 mg.
and dilute to 100 mL.
6.2.2 Atomic Absorption Spectrophotometer, with a flame-
less cold-vapor mercury analysis system.
8.10 Stannous Chloride Solution (100 g/L)—Dissolve 100 g
6.2.3 Digestion Vessels, 16- by 150-mm disposable glass
of stannous chloride dihydrate (SnCl ·2 H O) in 300 mL of
2 2
test tubes.
concentrated hydrochloric acid (HCl, sp. gr. 1.19) and CAU-
6.2.4 Heat Source, an aluminum block with 18-mm holes to
TIOUSLY dilute to 1 L with water. This solution is stable for
accommodate the disposable test tubes. The block shall be
approximately one week if refrigerated.
capable of slowly reaching and maintaining a final temperature
8.11 Certified Reference Material (CRM)—Use Certified
of 150°C. The block can be heated by placing it on a hot plate
Reference Material (CRM) coals with dry-basis mercury val-
or it can contain its own internal heating elements.
ues for which confidence limits are issued by a recognized
certifying agency such as the National Institute of Standards
7. Sample
andTechnology (NIST). It is recommended that the user verify
7.1 Prepare the analysis sample in accordance with Method
thevaluewiththecertifyingagencybeforeusingtheCRMcoal
D2013 by pulverizing the material to pass a 250-µm (No. 60)
for quality control purposes.
sieve.
7.2 Analyze separate test portions for moisture content in
9. Procedure
accordance with Test Method D3173 or Test Methods D5142.
9.1 Preparation of Test Solution A (Extraction Step):
9.1.1 Weigh a test portion of approximately1gofthe
Test Method A for the Analysis of Mercury by Using Acid
sample into a digestion bottle. Record the weight (Ws)tothe
Extraction
nearest 0.0001 g.
8. Reagents
9.1.2 Quantitatively add 2 mL of concentrated nitric acid
and 6 mL of concentrated hydrochloric acid to the digestion
8.1 Purity of Reagents—Reagent grade chemicals shall be
bottle and secure the cap.
used.Unlessotherwiseindicated,itisintendedthatallreagents
9.1.3 Transfer the digestion bottle and contents to a water
shall conform to the specifications of the Committee on
bath that has been heated to 80°C and heat for 1 h. Secure the
Analytical Reagents of the American Chemical Society where
digestionbottleinsuchawayastokeepthecontentsbelowthe
such specifications are available. Other grades can be used
surface of the water.
provided it is first ascertained that the reagent is of sufficiently
9.1.4 After 1 h, remove the digestion bottle and allow to
high purity to permit its use without lessening the accuracy of
cool to room temperature.
the determination.
NOTE 3—Caution: Carefully relieve the pressure by slowly removing
8.2 Purity of Acids—Use trace metal purity grade acids or
the cap.
equivalent. Redistilled acids are acceptable.
9.1.5 Add 36.5 mL of water and mix the contents.
8.3 Purity of Water—UsewaterequivalenttoASTMTypeII
9.1.6 Add 5 mL of 5 % potassium permanganate solution.
reagent water of Specification D1193.
Allow the mixture to stand for 10 min.
8.4 Mercury Standard Stock Solution [1000 ppm (1000
9.1.7 Add 0.5 mL of the hydroxylamine sodium chloride
µg/mL)]—Dissolve 1.0800 g of mercury (II) oxide (HgO) in a
solution and mix. If a pink color persists for more than 1 min,
minimum volume of HCl (1+1) and dilute to 1 L with water.
add an additional 0.5 mL of the hydroxylamine sodium
chloride solution and mix. Note the total volume and record
this volume (V) for use in the final calculations.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
9.2 Preparation of Reagent Blank—Prepare a reagent blank
listed by the American Chemical Society, see Analar Standards for Laboratory
byrepeatingtheprocedurein9.1butwithoutthetestportionof
Chemicals,BDHLtd.,Poole,Dorset,U.K.,andtheUnitedStatesPharmacopeiaand
National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD. the sample.
D6414 − 01 (2006)
9.3 Preparation of Control Sample: 9.4.3.4 Determine the absorbance (As ) of the Test Solution
A using the procedure described in 9.4.2.
9.3.1 PrepareatestportionofaCRMcoalforanalysisusing
the procedure described in 9.1. Record the expected value of 9.4.3.5 Using 10 % HCl, dilute test solutions with mercury
mercury, the certified value in the coal, as CRME.
absorbances greater than the highest calibration standard to
give an estimated absorbance equivalent to the 3-ng/mL
9.3.2 Alternatively, weigh a test portion of1gofa CRM.
After the addition of the nitric and hydrochloric acids to the calibration standard and reanalyze.
digestion bottle, add mercury standard solution (8.5). The 9.4.3.6 Record the dilution factor as DF.
volume of mercury standard solution to be added should yield
9.4.4 Analysis of the Reagent Blank—Determine the absor-
an amount of mercury approximately equivalent to that in the
bance (Ab) of the reagent blank using the procedure described
CRM coal (Note 4).
in 9.4.3.
9.3.3 Calculate the expected value of mercury CRME as
9.4.5 Analysis of the Quality Control Sample—Determine
follows
the absorbance (Aqs) of the quality control sample using the
procedure described in 9.4.3.
CRME 5 ~Wcrm*CRM1Vstandard*0.1!/Wcrm (1)
where:
Test Method B for the Analysis of Mercury by Using Wet
Oxidation Extraction
Wcrm = dry weight of the CRM coal used for prepara-
tion of the quality control sample, g;
CRM = certified value of mercury in the quality control 10. Reagents
sample;
10.1 Purity of Reagents—Reagent grade chemicals shall be
Vstandard = volume of mercury standard solution added to
used.Unlessotherwiseindicated,itisintendedthatallreagents
the digestion bottle, mL; and
shall conform to the specifications of the Committee on
0.1 = the concentration of the mercury standard
Analytical Reagents of the American Chemical Society where
solution, µg/mL.
such specifications are available. Other grades can be used
NOTE4—Atestportionof0.9-gdryweightofaCRMcoalwith0.11g/g
provided it is first ascertained that the reagent is of sufficiently
(110 ng/g) of mercury is weighed out as a quality control sample.To yield
high purity to permit its use without lessening the accuracy of
an amount approximately equivalent to that present in the CRM coal, 0.9
mL of the mercury standard solution is added to the digestion bottle after
the determination.
the addition of the nitric and hydrochloric acids. CRME calculates to 0.21
10.2 Purity of Acids—Use trace metal purity grade acids or
µg/g.
equivalent. Redistilled acids are acceptable.
9.4 Atomic Absorption Analyses:
10.3 Purity of Water—Use water equivalent to ASTM Type
9.4.1 Instrument Conditions—Follow the instrument manu-
facturers recommended procedure to align the optical cell in II reagent water of Specification D1193.
the beam path of the atomic absorption spectrophotometer and
10.4 Mercury Standard Stock Solution [1000 ppm (1000
optimize the performance of the instrument and the flameless
µg/mL)]—Dissolve 1.0800 g of mercury (II) oxide (HgO) in a
cold-vapor apparatus.
minimum volume of HCl (1+1) and dilute to 1 L with water.
9.4.2 Instrument Calibration:
Alternatively, use a commercially available stock solution
9.4.2.1 Prepare 50 mLof 0.5, 1, 3, 5, and 10 ng/mL(ppb) of
specifically prepared for atomic absorption spectrometry.
mercury calibration standards in a solution of 10 % HCl by
10.5 Mercury Standard Solution (100 ng/mL)—Prepare the
serial dilution of the mercury standard solution.
mercury standard solution fresh daily. Dilute 5 mL of the
9.4.2.2 Add a specified volume (Vcal) of a calibration
mercury standard stock solution to 500 mL with deionized
solution to the reduction flask or reduction system.
water. Further dilute 10 mLof this intermediate solution to 1 L
NOTE 5—If an autosampler equipped with a peristaltic pump is used for
with deionized water.
delivery of both calibration and analyses sample solutions to the reduction
10.6 Nitric Acid—Concentrated (HNO , sp. gr. 1.42).
system, a specific volume is not required.
9.4.2.3 Either manually or by means of an autosampling
10.7 Hydrochloric Acid—Concentrated (HCl, sp. gr. 1.19).
device begin the analyses of the calibration solution by adding
10.8 Sulfuric Acid—H SO , sp. gr. 1.83).
2 4
enough stannous chloride solution so as to ensure complete
10.9 Vanadium Pentoxide, V O —Remove traces of mer-
reduction of the mercury in the calibration solution.
2 5
cury by roasting the V O in a fume hood at a temperature
9.4.2.4 Record the absorbance of the calibration standard.
2 5
below 690°C, the melting point of V O , in a porcelain dish
Repeat for each calibration standard.
2 5
using a muffle furnace or a Fisher burner.
9.4.3 Analysis of Test Solution A:
9.4.3.1 Using the 20-cm syringe, draw Test SolutionAinto
NOTE 7—Warning: V O is highly toxic, an irritant, and a possible
2 5
the syringe.
mutagen.
9.4.3.2 Fit the syringe with a 1-µm filter.
10.10 Stannous Chloride Solution (100 g/L)—Dissolve 100
9.4.3.3 Filteravolumeequivalentto VcalofTestSolutionA
g of stannous chloride dihydrate (SnCl ·2H O) in 300 mL of
2 2
into the reduction flask or reduction system.
concentrate
...

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