ASTM D3761-96(2002)
(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
SIGNIFICANCE AND USE
This test method permits measurement of the fluorine content of coal for the evaluation of potential fluorine emission from coal combustion or conversion processes. When coal samples are combusted in accordance with this test method, the fluorine is quantitatively retained and is representative of the total fluorine concentration in whole coal.
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 Section 7.
1.5 All accountability and quality control aspects of Guide D 4621 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3761–96 (Reapproved 2002)
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 E144 Practice for Safe Use of Oxygen Combustion Bombs
1.1 This test method covers the analysis of total fluorine in
3. Summary of Test Method
coal.
3.1 Total fluorine is determined in this test method by
1.2 This test method was successfully tested on coals
2 combustingaweighedsampleinanoxygenbombwithadilute
containing 25% ash or less.
base absorbing the fluorine vapors. The bomb is rinsed into a
1.3 The values stated in SI units are to be regarded as the
beakerwithwaterandfollowingtheadditionofacitratebuffer,
standard. The values given in parentheses are for information
the fluorine is determined by ion-selective electrode.
only.
1.4 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 This test method permits measurement of the fluorine
responsibility of the user of this standard to establish appro-
contentofcoalfortheevaluationofpotentialfluorineemission
priate safety and health practices and determine the applica-
from coal combustion or conversion processes. When coal
bility of regulatory limitations prior to use. For specific hazard
samplesarecombustedinaccordancewiththistestmethod,the
statements, see Section 7.
fluorine is quantitatively retained and is representative of the
1.5 All accountability and quality control aspects of Guide
total fluorine concentration in whole coal.
D4621 apply to this test method.
5. Apparatus
2. Referenced Documents
3 5.1 Combustion Bomb, constructed of materials that are not
2.1 ASTM Standards:
affected by the combustion process or products. The bomb
D1193 Specification for Reagent Water
4 must be designed so that all liquid combustion products can be
D2013 Practice for Preparing Coal Samples for Analysis
quantitatively recovered by washing the inner surfaces. There
D3173 Test Method for Moisture in theAnalysis Sample of
4 must be no gas leakage during the test. The bomb must be
Coal and Coke
capable of withstanding a hydrostatic-pressure test to 20 MPa
D3180 Practice for Calculating Coal and Coke Analyses
4 (approximately 3000 psig) at room temperature without stress-
from As-Determined to Different Bases
ing any part beyond its elastic limit.
D4621 Guide for Quality Management in an Organization
4 5.2 Water Bath—A container large enough to hold the
That Samples or Tests Coal and Coke
combustion bomb and enough cooling water to dissipate the
D5142 TestMethodsforProximateAnalysisoftheAnalysis
5 heat generated during the combustion process. The container
Sample of Coal and Coke by Instrumental Procedures
shall be designed to allow a constant flow of water around the
combustion bomb.
5.3 Sample Holder—Samples shall be burned in an open
This test method is under the jurisdiction of ASTM Committee D05 on Coal
crucible of platinum, quartz, or acceptable base metal alloy.
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
Elements in Ash and Trace Elements of Coal. Base-metal alloy crucibles are acceptable if after a few
Current edition approved April 10, 2002. Published June 1996. Originally
preliminary firings the weight does not change significantly
published as D3761–79. Last previous edition D3761–96. DOI: 10.1520/D3761-
between tests.
96R02.
5.4 Ignition Wire, 100-mm, nickel-chromium alloy, No. 34
This standard is based on a published report by Thomas, J., Jr., and Gluskoter,
H.J.,“DeterminationofFluorideinCoalwiththeFluorideIon-SpecificElectrode,”
B & S gage, or platinum, No. 34 or No. 38B&S gage.
Analytical Chemistry, Vol 46, 1974, pp. 1321–23.
5.5 Ignition Circuit—A6 to 16-V alternating or direct cur-
Annual Book of ASTM Standards, Vol 11.01.
rent is required for ignition purposes with an ammeter or pilot
Annual Book of ASTM Standards, Vol 05.06.
Annual Book of ASTM Standards, Vol 14.04. light in the circuit to indicate when current is flowing. A
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3761–96 (2002)
step-down transformer connected to an alternating-current 7. Hazards
lighting circuit or batteries may be used.
7.1 Precautions—The following precautions are recom-
5.6 Balance, analytical, with a sensitivity of 0.1 mg. The
mended for safe operations in the use of the oxygen combus-
balanceshallbecheckedperiodicallytodetermineitsaccuracy.
tion bomb.Additional precautions are given in Practice E144,
5.7 Specific-Ion Meter—A pH meter with an expandable
for use of oxygen combustion bombs. Consult the manufactur-
millivolt scale, specific-ion meter, sensitive to 0.1 mV, suitable
er’s installation and operating manuals before using the calo-
for method of standard addition determinations.
rimeter.
5.8 Electrodes, fluoride-sensing, with the appropriate
7.1.1 The mass of coal sample and the pressure of the
reference-typeelectrodeasrecommendedbythemanufacturer.
oxygen admitted to the bomb must not exceed the bomb
5.9 Laboratory Ware—All laboratory ware, for example,
manufacturer’s recommendations.
beakers, bottles, and so forth, used for solutions containing
7.1.2 Inspect the bomb parts carefully after each use.
fluoride ions must be made of polyethylene or a heat-resistant
Frequently check the threads on the main closure for wear.
polymer such as polypropylene.
Replace the cracked or significantly worn parts. Return the
bomb to the manufacturer occasionally for inspection and
6. Reagents
possibly proof testing.
6.1 Purity of Reagents—Reagent grade chemicals shall be
7.1.3 The oxygen supply cylinder should be equipped with
used in all tests. Unless otherwise indicated, it is intended that
an approved type of safety device, such as a reducing valve, in
all reagents shall conform to the specifications of the Commit-
addition to the needle valve and pressure gage used in
tee onAnalytical Reagents of theAmerican Chemical Society,
regulating the oxygen feed to the bomb. Valves, gages, and
where such specifications are available. Other grades may be
gaskets must meet industry safety code. Suitable reducing
used, provided it is first ascertained that the reagent is of
valves and adaptors for 3 to 5-MPa (approximately 400 to
sufficiently high purity to permit its use without lessening the
600-psi ) discharge pressure are obtainable from commercial
accuracy of the determination.
sources of compressed-gas equipment. Check the pressure
6.2 Reagent Water—Reagent water, conforming to Type IV
gage periodically for accuracy.
of Specification D1193, shall be used for preparation of
7.1.4 During ignition of a sample, the operator must not
reagents and washing of the bomb interior. (Warning—Some
permit any portion of his body to extend over the calorimeter.
reagents used in this test method are hazardous. Follow the
7.1.5 Exercise extreme caution when combustion aids are
precautions listed in the Material Safety Data Sheet of the
employed so as not to exceed the bomb manufacturer’s
manufacturer for each reagent.)
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
unless thoroughly mixed with the coal sample.
3 6 5 7 2 3
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.
3-MPa (30-atm) pressure with oxygen, if the bomb has been
6 8 7
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)—
8. Sample
Dissolve40gofsodiumhydroxide(NaOH)inwateranddilute
8.1 Prepare the analysis sample in accordance with Method
to1L.
D2013 to pass through a 250-µm (60-mesh) sieve. Pulverize
6.8 Sulfuric Acid, Standard (5.0 N)—Cautiously dilute 142
the analysis sample to pass a 150-µm (100-mesh) sieve.
mL of sulfuric acid (H SO , sp gr 1.834
...
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