ASTM D3761-96
(Test Method)Standard Test Method for Total Fluorine in Coal by the Oxygen Bomb Combustion/Ion Selective Electrode Method
Standard Test Method for Total Fluorine in Coal by the Oxygen Bomb Combustion/Ion Selective Electrode Method
SCOPE
1.1 This test method covers the analysis of total fluorine in coal.
1.2 This test method was successfully tested on coals containing 25% ash or less.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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. For specific hazard statements, see Note 1 and Section 7.
1.5 All accountability and quality control aspects of Guide D4621 apply to this test method.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
Designation:D3761–96
Standard Test Method for
Total Fluorine in Coal by the Oxygen Bomb Combustion/Ion
Selective Electrode Method
This standard is issued under the fixed designation D3761; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Summary of Test Method
1.1 This test method covers the analysis of total fluorine in 3.1 Total fluorine is determined in this test method by
coal. combustingaweighedsampleinanoxygenbombwithadilute
1.2 This test method was successfully tested on coals base absorbing the fluorine vapors. The bomb is rinsed into a
containing 25% ash or less. beakerwithwaterandfollowingtheadditionofacitratebuffer,
1.3 The values stated in SI units are to be regarded as the the fluorine is determined by ion-selective electrode.
standard. The values given in parentheses are for information
4. Significance and Use
only.
4.1 This test method permits measurement of the fluorine
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the contentofcoalfortheevaluationofpotentialfluorineemission
from coal combustion or conversion processes. When coal
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- samplesarecombustedinaccordancewiththistestmethod,the
fluorine is quantitatively retained and is representative of the
bility of regulatory limitations prior to use. For specific hazard
statements, see Note 1 and Section 7. total fluorine concentration in whole coal.
1.5 All accountability and quality control aspects of Guide
5. Apparatus
D4621D4621 apply to this test method.
5.1 Combustion Bomb, constructed of materials that are not
2. Referenced Documents
affected by the combustion process or products. The bomb
must be designed so that all liquid combustion products can be
2.1 ASTM Standards:
D1193 Specification for Reagent Water quantitatively recovered by washing the inner surfaces. There
must be no gas leakage during the test. The bomb must be
D2013 Method of Preparing Coal Samples for Analysis
D3173 TestMethodforMoistureintheAnalysisSampleof capable of withstanding a hydrostatic-pressure test to 20 MPa
(approximately 3000 psig) at room temperature without stress-
Coal and Coke
D3180 Practice for Calculating Coal and Coke Analyses ing any part beyond its elastic limit.
5.2 Water Bath—A container large enough to hold the
from As-Determined to Different Bases
D4621 GuideforAccountabilityandQualityControlinthe combustion bomb and enough cooling water to dissipate the
heat generated during the combustion process. The container
Coal Analysis Laboratory
D5142 Test Methods for ProximateAnalysis of theAnaly- shall be designed to allow a constant flow of water around the
combustion bomb.
sis Sample of Coal and Coke by Instrumental Procedures
E 144 Practice for Safe Use of Oxygen Combustion 5.3 Sample Holder—Samples shall be burned in an open
crucible of platinum, quartz, or acceptable base metal alloy.
Bombs
Base-metal alloy crucibles are acceptable if after a few
preliminary firings the weight does not change significantly
ThistestmethodisunderthejurisdictionofASTMCommitteeD-5onCoaland
between tests.
CokeandisthedirectresponsibilityofSubcommitteeD05.29onMajorElementsin
5.4 Ignition Wire, 100-mm, nickel-chromium alloy, No. 34
Ash and Trace Elements of Coal.
Current edition approved April 10, 1996. Published June 1996. Originally
B & S gage, or platinum, No. 34 or No. 38B&S gage.
published as D3761–79. Last previous edition D3761–91.
5.5 Ignition Circuit—A 6 to 16-V alternating or direct
This standard is based on a published report by Thomas, J., Jr., and Gluskoter,
current is required for ignition purposes with an ammeter or
H.J.,“DeterminationofFluorideinCoalwiththeFluorideIon-SpecificElectrode,”
Analytical Chemistry, Vol 46, 1974, pp. 1321–23. pilot light in the circuit to indicate when current is flowing.A
Annual Book of ASTM Standards, Vol 11.01.
step-down transformer connected to an alternating-current
Annual Book of ASTM Standards, Vol 05.05.
lighting circuit or batteries may be used.
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D3761–96
5.6 Balance, analytical, with a sensitivity of 0.1 mg. The 7. Hazards
balanceshallbecheckedperiodicallytodetermineitsaccuracy.
7.1 Precautions—The following precautions are recom-
5.7 Specific-Ion Meter—A pH meter with an expandable
mended for safe operations in the use of the oxygen combus-
millivolt scale, specific-ion meter, sensitive to 0.1 mV, suitable
tion bomb. Additional precautions are given in Practice
for method of standard addition determinations.
E144E144,foruseofoxygencombustionbombs.Consultthe
5.8 Electrodes, fluoride-sensing, with the appropriate
manufacturer’sinstallationandoperatingmanualsbeforeusing
reference-typeelectrodeasrecommendedbythemanufacturer.
the calorimeter.
5.9 Laboratory Ware—All laboratory ware, for example,
7.1.1 The mass of coal sample and the pressure of the
beakers, bottles, and so forth, used for solutions containing oxygen admitted to the bomb must not exceed the bomb
fluoride ions must be made of polyethylene or a heat-resistant
manufacturer’s recommendations.
polymer such as polypropylene.
7.1.2 Inspect the bomb parts carefully after each use.
Frequently check the threads on the main closure for wear.
6. Reagents Replace the cracked or significantly worn parts. Return the
bomb to the manufacturer occasionally for inspection and
6.1 Purity of Reagents—Reagent grade chemicals shall be
possibly proof testing.
used in all tests. Unless otherwise indicated, it is intended that
7.1.3 The oxygen supply cylinder should be equipped with
all reagents shall conform to the specifications of the Commit-
an approved type of safety device, such as a reducing valve, in
tee onAnalytical Reagents of theAmerican Chemical Society,
7 addition to the needle valve and pressure gage used in
where such specifications are available. Other grades may be
regulating the oxygen feed to the bomb. Valves, gages, and
used, provided it is first ascertained that the reagent is of
gaskets must meet industry safety code. Suitable reducing
sufficiently high purity to permit its use without lessening the
valves and adaptors for 3 to 5-MPa (approximately 400 to
accuracy of the determination.
600-psi ) discharge pressure are obtainable from commercial
6.2 Reagent Water—Reagent water, conforming to Type IV
sources of compressed-gas equipment. Check the pressure
ofSpecificationD1193D1193,shallbeusedforpreparationof
gage periodically for accuracy.
reagents and washing of the bomb interior.
7.1.4 During ignition of a sample, the operator must not
NOTE 1—Warning:Somereagentsusedinthistestmethodarehazard-
permit any portion of his body to extend over the calorimeter.
ous.FollowtheprecautionslistedintheMaterialSafetyDataSheetofthe
7.1.5 Exercise extreme caution when combustion aids are
manufacturer for each reagent.
employed so as not to exceed the bomb manufacturer’s
recommendations and to avoid damage to the bomb. Do not
6.3 Buffer Solution—Dissolve 294 g of sodium citrate
fire loose fluffy material such as unpelleted benzoic acid,
(Na C H O ·2H O) and 20.2 g of potassium nitrate (KNO)in
3 6 5 7 2 3
unless thoroughly mixed with the coal sample.
approximately 850 mL of water. Adjust the pH to 6.0 with
7.1.6 Donotfirethebombifithasbeenfilledtogreaterthan
crystalline citric acid (C H O ) and dilute to 1 L with water.
6 8 7
3-MPa (30-atm) pressure with oxygen, if the bomb has been
6.4 Standard Fluoride Stock Solution (1000 Mg/g)—
dropped or turned over after loading, or if there is evidence of
Dissolve 2.2101 6 0.0002 g of Sodium Fluoride (NaF) in
a gas leak when the bomb is submerged in the calorimeter
wateranddiluteto1L.Mixwell.DrytheNaFfor1hat105°C
water.
and cool to room temperature in a desiccator before weighing.
7.1.7 Hydrofluoric acid (HF) is very corrosive and may
6.5 Standard Fluoride Stock Solution (100 Mg/g)—Dilute
hasten corrosion problems with the combustion bomb.
10.0 mL of fluoride stock solution (6.4) to 100 mL in a
7.1.8 For manually operated calorimeters, the ignition cir-
volumetric flask with water. Mix well.
cuit switch shall be of the momentary double-contact type,
6.6 Oxygen,freeofcombustiblematterandguaranteedtobe
normally open, except when held closed by the operator. The
99.5% pure.
switch shall be depressed only long enough to fire the charge.
6.7 Sodium Hydroxide, Standard Solution (1.0 N)—
Dissolve40gofsodiumhydroxide(NaOH)inwateranddilute
8. Sample
to1L.
8.1 Prepare the analysis sample in accordance with Method
6.8 Sulfuric Acid, Standard (5.0 N)—Cautiously dilute 142
D2013D2013 to pass through a 250-µm (60-mesh) sieve.
mL of sulfuric acid (H SO , sp gr 1.834 to 1.836) to 1 L with
2 4
Pulverize the analysis sample to pass a 150-µm (100-mesh)
water.
sieve.
6.9 Sulfuric Acid, Standard (0.5 N)—Cautiously dilute 100
8.2 Analyze a separate portion of the analysi
...
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