ASTM D5987-96(2002)
(Test Method)Standard Test Method for Total Fluorine in Coal and Coke by Pyrohydrolytic Extraction and Ion Selective Electrode or Ion Chromatograph Methods
Standard Test Method for Total Fluorine in Coal and Coke by Pyrohydrolytic Extraction and Ion Selective Electrode or Ion Chromatograph Methods
SCOPE
1.1 This test method covers the analysis of total fluorine in coal and coke.
1.2 This analysis was successfully tested on coals containing 37 % ash or less (see AS 1038.10.4 and Conrad).
1.3 The values stated in SI units shall be regarded as 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 4.
1.5 All accountability and quality control aspects of Guide D 4621 apply to this test method.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D5987–96 (Reapproved 2002)
Standard Test Method for
Total Fluorine in Coal and Coke by Pyrohydrolytic
Extraction and Ion Selective Electrode or Ion
Chromatograph Methods
This standard is issued under the fixed designation D5987; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D5142 Test Methods for the Proximate Analysis of the
Analysis Sample of Coal or Coke by Instrumental Proce-
1.1 This test method covers the analysis of total fluorine in
dures
coal and coke.
2.2 Australian Standard:
1.2 This analysis was successfully tested on coals contain-
AS 1038.10.4 Determination of Trace Elements—Coal,
ing 37% ash or less (see AS1038.10.4 and Conrad ).
Coke and Fly-Ash-Determination of Fluorine Content—
1.3 The values stated in SI units shall be regarded as
Pyrohydrolysis Method
standard. The values given in parentheses are for information
only.
3. Summary of Test Method
1.4 This standard does not purport to address all of the
3.1 Total fluorine is determined in this test method by first
safety concerns, if any, associated with its use. It is the
subjecting the weighed test portion to pyrohydrolytic condi-
responsibility of the user of this standard to establish appro-
tions which separate fluorine from the coal/coke matrix. The
priate safety and health practices and determine the applica-
pyrohydrolysate is then gravimetrically processed and final
bility of regulatory limitations prior to use. For specific hazard
determinations are made by either ion-selective electrode or
statements see Note 4.
ion chromatographic techniques.
1.5 All accountability and quality control aspects of Guide
D4621 apply to this test method.
4. Significance and Use
4.1 This test method permits measurement of the fluorine
2. Referenced Documents
contentofcoalandcokefortheevaluationofpotentialfluorine
2.1 ASTM Standards:
emissionfromcoalcombustionorconversionprocesses.When
D346 Practice for Collection and Preparation of Coke
3 coal samples are combusted in accordance with this test
Samples for Laboratory Analysis
4 method, the fluorine is quantitatively released from the coal
D1193 Specification for Reagent Water
3 and retained in the pyrohydrolysate so that it is representative
D2013 Practice for Preparing Coal Samples for Analysis
3 of the total fluorine concentration in coal.
D2234 Practice for Collection of a Gross Sample of Coal
D3173 TestMethodforMoistureintheAnalysisSampleof
5. Apparatus
Coal and Coke
5.1 Laboratory Ware—Exceptasnoted,alllaboratoryware,
D3180 Practice for Calculating Coal and Coke Analyses
for example, volumetric flasks, beakers, bottles, etc., used for
from As-Determined to Different Bases
solutions containing fluoride ions must be made of polyethyl-
D4621 Guide for Quality Managment in an Organization
3 ene, polystyrene, or a heat-resistant polymer such as polypro-
that Samples or Tests Coal and Coke
pylene.
5.2 Vials—Glass or polystyrene, 10 to 30-mLcapacity with
This test method is under the jurisdiction of ASTM Committee D05 on Coal tightly fitting snap-on plastic lids.
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
5.3 Bottles—Polypropylene, 125-mLcapacity, wide-mouth,
Elements in Ash and Trace Elements of Coal.
with liner-less leakproof polyethylene screw cap, for tube-
Current edition approved July 10, 1996. Published September 1996. Originally
furnace pyrohydrolysate processing.
published as D5987–96. Last previous edition D5987–96.
Conrad, V. B., and Brownlee, W. D., “Hydropyrolytic—Ion Chromatographic
DeterminationofFluorideinCoalandGeologicalMaterials,” Analytical Chemistry,
Vol 60, No. 4, 1988, pp. 365–369.
3 5
Annual Book of ASTM Standards, Vol 05.06. Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Annual Book of ASTM Standards, Vol 11.01. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5987
5.4 Vials—Polystyrene, 70-mL capacity, with liner-less 5.9.1 Silica Tube-Furnace and Accessories:
leakproof polyethylene screw cap.
5.9.1.1 Quartz Combustion Tube—Translucent, pure silica
5.5 DispensingBottles—Polyethylene,250-mLcapacity,for
(25-mm outside diameter, 20-mm inside diameter) of length
the standard fluorine solution (6.3.1) and of 600-mL capacity
appropriate to the particular furnace used. Preferably, the gas
for the absorption solution (6.3.3) and buffer (6.3.5).
outlet end should be narrowed to a tubulure of approximately
5.6 Micropipettes—Polypropylene or other suitable poly-
7 mm in diameter.
mer, variable volumes ranging from 0.1 mLto at least 2.0 mL.
NOTE 1—Combustion tubes of alternative refractory compositions do
This is a satisfactory alternative to the 250-mL dispensing
nothaveadequatethermalstresscharacteristicsforoperationwiththistest
bottle (5.5), for the delivery of small volumes of the standard
method.
fluorine solution.
5.9.1.2 SiliconeStoppers—20mmindiameter,positionedat
5.7 Glass Dropper Bottle—30-mL capacity for dispensing
inlet end and outlet, if applicable, of silica combustion tube
glacial acetic acid.
(5.9.1.1).
5.8 Balance—Analytical, with a sensitivity of 0.1 mg. The
5.9.1.3 Combustion Boats—Unglazed porcelain, high alu-
balanceshallbecheckedperiodicallytodetermineitsaccuracy.
5.9 Apparatus for Tube-Furnace Pyrohydrolysis (see Fig. mina content, approximately 97 mm by 16 mm by 12 mm,
1): preheated at 1000°C for 1 h.
FIG. 1 Pyrohydrolysis Furnace and Fluorine Absorption Assembly
D5987
5.9.1.4 Silica Pusher and T-Tube—A silica push rod of Society, where such specifications are available. Other grades
dimensions 5 mm in diameter by 50 cm long, fused at one end may be used, provided it is first ascertained that the reagent is
to provide a flat disk surface of 10 to 12 mm in diameter and of sufficiently high purity to permit its use without lessening
having a piece of magnetic steel affixed to the other end by the accuracy of the determination.
epoxy resin. The T-tube, 50 cm long, is composed of borosili- 6.2 Reagent Water—Reagent water conforming to type IV
cate glass and protrudes 10 mm into the silica tube (5.9.1.1) of Specification D1193, shall be used in all cases unless
through a stopper (5.9.1.2). A magnet is used to move the otherwise indicated. (Warning—Some reagents used in this
pusher inside the T-tube. test method are hazardous. Follow the precautions listed in the
5.9.1.5 Combustion Furnace—Capable of reaching a maxi- Material Safety Data Sheets of the manufacturer for each
mum temperature of at least 1100°C. reagent.)
5.9.1.6 Heating Tape and Power Regulator—To prevent 6.3 Solutions for ISE Test Method:
condensationfromformingintheoutletendofthecombustion 6.3.1 Standard Fluoride Solution (1 g = 200 µg
train. fluoride)—The following standard fluoride solutions are re-
5.9.2 Steam Generator (Fig. 1): quired:
5.9.2.1 Round Bottom Flask—Glass, 2-L capacity. 6.3.1.1 For Direct Comparison Method—Dissolve 0.2210
5.9.2.2 Heating Mantle—Ofsizesufficienttoheattheround 6 0.0002 g of dry (110°C for 1 h) sodium fluoride in
bottom flask (5.9.1.1). approximately 400 mL of water in a 500-mL polypropylene
5.9.2.3 Y-piece—Glass, 10 mm in diameter. beaker. Transfer by thorough rinsing with water to a 500-mL
5.9.2.4 Gas Distribution Tube—Zero porosity. polypropylene volumetric flask. Dilute to mark with water and
5.9.2.5 Stopcocks—One three-way and one two-way. mix. Discard after one month.
5.9.2.6 Flowmeter—Capableofregulatinganddeliveringat
NOTE 3—There will not be a classic meniscus in polypropylene
least 1000 mL/min of the oxygen.
volumetrics. The solution will correctly appear to have a flat surface.
5.9.3 Absorption Vessel Components:
6.3.1.2 For Analyte-Addition Test Method—Dissolve
5.9.3.1 Separatory Funnel—Glass, 125-mL capacity for
0.2210 6 0.0002 g of dry (110°C for 1 h) sodium fluoride in a
rinsing Graham Condenser into receiving flask, with stopcock
500-mLpolypropylenebeakercontaining150mLofwaterand
and 24/40 joint with drip tip.
250mLofanunspikedbufferedabsorptionsolution(see6.3.3).
5.9.3.2 Graham Condenser—For condensing hydropyroly-
Transfer,bythoroughrinsingwithwater,toa500-mLpolypro-
sate, with 24/40 outer joint at top. Water jacket length should
pylenevolumetricflask.Dilutewithwatertothemarkandmix.
be 300 mm.
Discard after one month (see Note 3).
5.9.3.3 Receiving Flask—250-mL capacity, flat bottom,
6.3.2 Absorption Solution (0.025 M NaOH)—Dissolve 2.0
wide neck, and tooled mouth, for collection of pyrohydroly-
g of sodium hydroxide in about 500 mL of water. Transfer to
sate.
a 2.0-L polypropylene flask, dilute to mark with water, and
5.10 Ion-specific Electrode (ISE) Measurement Apparatus:
mix.
5.10.1 Specific Ion Meter—ApH meter with an expandable
6.3.3 Unspiked Buffered Absorption (pH 6.5)—Dissolve
millivolt scale sensitive to 0.1 mV, specific-ion meter or
10.0gofpotassiumnitrate,2.0gofsodiumhydroxide,and115
equivalent, suitable for method of standard addition determi-
g of ammonium acetate in 1700 mLof water.Adjust pH to 6.5
nations.
with a small amount of glacial acetic acid. Transfer to a 2.0-L
5.10.2 Electrodes—Solid-state fluoride sensing, with the
polypropylene flask, dilute to mark with water, and mix.
appropriate reference-type electrode as recommended by the
6.3.4 Buffer Added After Tube-Furnace Hydrolysis (pH
manufacturer.
6.5)—Dissolve 10.0 g of potassium nitrate and 115 g of
NOTE 2—The fluoride sensing element should be polished frequently
ammonium acetate in 350 mL of water.Adjust pH to 6.5 with
and in accordance with the manufacturer’s suggestions to prolong its
a small amount of glacial acetic acid. Transfer to a 500-mL
optimal performance.
polypropylene volumetric flask, dilute to mark with water, and
5.10.3 Magnetic Stirrer—Complete with polytetrafluoroet-
mix.
hylene(PTFE)stirringbarsandmagnetforconvenientremoval
6.3.5 Solution for Conditioning Fluoride ISE—Using a
of bars from vials.
pipette, transfer 20.0 mL of water, 20.0 mL of absorbing
5.11 Ion-Chromatograph (IC)—Equipped with three, 3 by
solution (6.3.2), and 10.0 mL of buffer (6.3.4) into a polysty-
250-mmAS-3anionseparatorcolumnsandafibersuppressor.
rene vial (5.2). Add 200 µL of standard fluoride solution
(6.3.1.1) and mix.
6. Reagents
6.4 Solutions for Ion-Chromatographic Measurement:
6.1 Purity of Reagents—Reagent grade chemicals shall be
6.4.1 Standard Fluoride Solution (1000 µg/mL fluoride)—
used in all tests. Unless otherwise indicated, it is intended that
Dissolve 2.2110 6 0.0002 g of dry (105°C for 1 h) sodium
all chemicals shall conform to the specifications of the com-
mittee on Analytical Reagents of the American Chemical
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Midgley, D., and Torrance, K., “Potentiometric Water Analysis,” John Wiley Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and Sons, 1978. and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Rice, T. D., Analytica Chimica Acta, 1983, 151, pp. 383–389. MD.
D5987
fluorideina250-mLpolypropylenebeakercontainingapproxi- 8.2.2.1 Add 50 6 1 mL of the appropriate absorption
mately150mLofwater.Transferwiththoroughrinsesofwater solution (6.3.2) for ISE finish or 65 6 1 mL of the absorption
toa1.0-Lpolypropylenevolumetricflask.Dilutewithwaterto solution (6.4.5) for the IC finish to a clean receiving flask
the mark and mix (see Note 3). (5.9.3). Place the flask underneath the condenser. Ensure that
6.4.2 Standard Fluoride Solution (1.0 µg/mL fluoride)— cooling water is passing through the condenser.
Transfer, by means of polypropylene pipette, 1.0 mL of 8.2.2.2 Allow oxygen to flow, bypassing the steam genera-
standard fluoride solution (6.4.1) to a 1.0-L polypropylene tor, at 750 mL/min into the furnace. Place the analysis sample
volumetric flask; dilute to mark with water and mix (see Note boatintoazoneatwhichthetemperatureofthesamplewillnot
3). Prepare fresh solution daily. exceed 300°C. Redirect the oxygen flow through the steam
6.4.3 SulfuricAcid, Standard (2.5 N)—Cautiouslydilute71 generator and into the furnace. At subsequent intervals of
mL of sulfuric acid (H SO , sp gr 1.834 to 1.836) to 1 L with approximately 30 s, push the analysis sample boat into hotter
2 4
water. Mix well. zones with the temperature not exceeding 400, 500, 750, and
6.4.4 Sulfuric Acid, Standard (0.025 N)—For use as sup- 1000°C, with a final push into the hottest zone.
pressor regenerator. Using a pipette, cautiously dilute 10.0 mL 8.2.2.3 Continue the pyrohydrolysis for a further 15 min,
of 2.5 N H SO (6.4.3) to 1 L with water. Mix well. while monitoring the flow of oxygen and the level of water in
2 4
the round bottom flask.
6.4.5 Sodium Bicarbonate Solution (0.0015 M)—Weakelu-
8.2.3 Pyrohydrolysate Processing for ISE Finish:
ent, for use as the absorbing solution and the Graham con-
8.2.3.1 At the completion of the pyrohydrolysis time, redi-
denser rinsing solution. Dissolve 0.2520 g of dry (105°C for 1
h) NaHCO in water and dilute to 2.0 L. Mix well. rect the oxygen flow around the steam generator and allow
excess steam to escape.
6.4.6 Sodium Bicarbonate Solution (0.02 M)—Strong elu-
ent.Dissolve1.6801gofdry(105°Cfor1h)NaHCO inwater
NOTE 4—Caution should be exercised as to the direction in which the
and dilute to 1.0-L. Mix well.
steam is vented. Preferably it should be allowed to escape into a sink or
6.5 Oxygen—Free of combustible matter and guaranteed to
similar facility.
be 99.5% pure.
8.2.3.2 Rinsethecondenserwithtwo5-mLaliquotsofwater
6.6 Helium—Refer to ion chromatograph manufacturer’s
through the separatory funnel (5.9.3.1).
recommendations for gas specifications.
8.2.3.3 Rinse the pyrohydrolysate into a tared polypropy-
lenebottle(5.3)withasmallamountofwaterandallowtocool
7. Sample
to room temperature.
7.1 Prepare the analysis sample in accordance with Method
NOTE 5—With an oxygen flow of 750 mL/min, the correct heating rate
D2013 or Practice D346 to pass a 250-µm (60-mesh) sieve.
on the steam generator and controlled washings, the total mass of
Pulverize the analysis sample to pass a 75-µm (200-mesh)
pyrohydrolysate at this stage should be approximately 100 g.
sieve.
8.2.3.4 Place the bottle containing the pyrohydrolysate on
7.2 Analyze a separate portion of the analysis sam
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