ASTM D4208-88(2002)

Standard Test Method for Total Chlorine in Coal by the Oxygen Bomb Combustion/Ion Selective Electrode Method

SCOPE
1.1 This test method covers the analysis of total chlorine in coal.
1.2 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.

General Information

• Status: Historical
• Publication Date: 29-Sep-1988
• ICS: 75.160.10 - Solid fuels
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.21 - Methods of Analysis

Relations

• Replaces: ASTM D4208-88(1997) - Standard Test Method for Total Chlorine in Coal by the Oxygen Bomb Combustion/Ion Selective Electrode Method
• Effective Date: 30-Sep-1988

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 4208 – 88 (Reapproved 2002)
Standard Test Method for
Total Chlorine in Coal by the Oxygen Bomb Combustion/Ion
Selective Electrode Method
This standard is issued under the fixed designation D4208; 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.
1. Scope 5. Apparatus
1.1 This test method covers the analysis of total chlorine in 5.1 Combustion Bomb, constructed of materials that are not
coal. affected by the combustion process or products. The bomb
1.2 This standard does not purport to address all of the must be designed so that all liquid combustion products can be
safety concerns, if any, associated with its use. It is the quantitatively recovered by washing the inner surfaces. There
responsibility of the user of this standard to establish appro- must be no gas leakage during the test. The bomb must be
priate safety and health practices and determine the applica- capableofwithstandingahydrostatic-pressuretestto3000psig
bility of regulatory limitations prior to use. (approximately20MPa)atroomtemperaturewithoutstressing
any part beyond its elastic limit.
2. Referenced Documents
5.2 Water Bath—A container large enough to hold the
2.1 ASTM Standards:
combustion bomb and enough cooling water to dissipate the
D1193 Specification for Reagent Water heat generated during the combustion process. The container
D3173 TestMethodforMoistureintheAnalysisSampleof
shall be designed to allow a constant flow of water around the
Coal and Coke combustion bomb.
D3180 Practice for Calculating Coal and Coke Analysis
5.3 Combustion Crucibles—Samples shall be burned in an
from As-Determined to Different Bases open crucible of platinum, quartz, or acceptable base-metal
E 144 Practice for Safe Use of Oxygen Combustion
alloy.
Bombs 5.4 Firing Wire, 100-mm, nickel-chromium alloy, No. 34B
&S gage, or platinum, No. 34 or No. 38B& S gage.
3. Summary of Test Method
5.5 Firing Circuit—A6to16-Valternatingordirectcurrent
3.1 Total chlorine is determined in this method by combus-
is required for ignition purposes with an ammeter or pilot light
ting a weighed sample in an oxygen bomb with dilute base
in the circuit to indicate when current is flowing.Astep-down
adsorbingthechlorinevapors.Thebombisrinsedintoabeaker
transformer connected to an alternating-current lighting circuit
with water and following the addition of an ionic strength
or batteries can be used. (Warning—The ignition circuit
adjuster, the chloride is determined by ion-selective electrode.
switch shall be of the momentary double-contact type, nor-
mally open, except when held closed by the operator. The
4. Significance and Use
switch should be depressed only long enough to fire the
4.1 The purpose of this test method is to measure the total
charge.)
chlorine content of coal. The chlorine content of coals may be
5.6 Balance, analytical, with a sensitivity of 0.1 mg.
useful in the evaluation of slagging problems, corrosion in
5.7 Specific-Ion Meter—A pH meter with an expandable
engineering processes, and in the total analysis of coal and
millivolt scale, specific-ion meter, sensitive to 0.1 mV, suitable
coke. When coal samples are combusted in accordance with
for method of standard addition determinations.
this method, the chlorine is quantitatively retained and is
5.8 Electrodes, chloride-sensing, with the appropriate
representative of the total chlorine content of the whole coal.
reference-typeelectrodeasrecommendedbythemanufacturer.
6. Reagents
This test method is under the jurisdiction of ASTM Committee D05 on Coal
6.1 Purity of Reagents—Reagent grade chemicals shall be
and Coke and is the direct responsibility of Subcommittee D05.21 on Methods of
Analysis. used in all tests. Unless otherwise indicated, it is intended that
Current edition approved Sept. 30, 1988. Published November 1988. Originally
published as D4208–82. Last previous edition D4208–88 (1997).
Annual Book of ASTM Standards, Vol 11.01.
3 5
Annual Book of ASTM Standards, Vol 05.06. Midgley, D., and Torrance, K., Potentiometric Water Analysis, John Wiley and
Annual Book of ASTM Standards, Vol 14.04. Sons, 1978.
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.
D 4208 – 88 (2002)
all reagents shall conform to the specifications of the Commit- 8.3.1 The weight of coal sample and the pressure of the
tee onAnalytical Reagents of theAmerican Chemical Society, oxygen admitted to the bomb must not exceed the bomb
where such specifications are available. Other grades may be manufacturer’s recommendation.
used, provided it is first ascertained that the reagent is of 8.3.2 Inspect the bomb parts carefully after each use.
sufficiently high purity to permit its use without lessening the Frequently check the threads on the main closure for wear.
accuracy of the determination. Replace the cracked or significantly worn parts. Return the
6.2 Purity of Water, deionized, high-purity, low-specific bomb to the manufacturer occasionally for inspection and
conductivity, Type II reagent water as defined in Specification possibly proof testing.
D1193D1193. 8.3.3 The oxygen supply cylinder should be equipped with
6.3 Ionic Strength Adjuster Solution (5M NaNO )— an approved type of safety device, such as a reducing valve, in
Dissolve 42.5 g of sodium nitrate in 100 mL water. addition to the needle valve and pressure gage used in
6.4 Sodium Carbonate Solution (Na CO )(2%)—Dissolve regulating the oxygen feed to the bomb. Valves, gages, and
2 3
2.0 g of sodium carbonate in 100 mL water. gaskets must meet industry safety code. Suitable reducing
6.5 Chloride, Standard Stock Solution (1000 µg/mL)— valves and adaptors for 300 to 500-psi (approximately 3 to
Dissolve 1.6486 g of sodium chloride (NaCl) in water and 5-MPa) discharge pressure are obtainable from commercial
dilute to 1 L. The NaCl should be dried for1hat 105°C and sources of compressed-gas equipment. Check the pressure
cooled to room temperature in a desiccator before weighing. gage periodically for accuracy.
6.6 Chloride, Standard Stock Solution (100 µg/mL)—Dilute 8.3.4 During ignition of a sample, the operator must not
10.0 mL of chloride stock solution to 100 mL in a volumetric permit any portion of his body to extend over the combustion
flask with water. bomb or its container.
6.7 Oxygen,freeofcombustiblematterandguaranteedtobe 8.3.5 Exercise extreme caution when combustion aids are
99.99% pure. employed so as not to exceed the bomb manufacturer’s
recommendations and to avoid damage to the bomb.
7. Sample
8.3.6 Admit oxygen slowly into the bomb to avoid blowing
7.1 A convenient sample is the air-dried coal that must be
powdered material from the crucible.
pulverized to pass a No. 60 (250-µm) sieve. 8.3.7 Donotfirethebombifithasbeenfilledtogreaterthan
7.2 A separate portion of the analysis sample shall be
30 atm (3 MPa) pressure with oxygen, if the bomb has been
analyzed simultaneously for moisture content in accordance dropped or turned over after loading, or if there is evidence of
with Test Method D3173D3173 if calculation to other than
a gas leak when the bomb is submerged in the water bath.
the as-determined basis is desired. 8.4 Place the bomb in a cooling water bath, with water
moving.Attach the ignition wires from the firing circuits, and
8. Procedure for Bomb Combustion
ignite the sample. Allow the bomb to remain in the cooling
8.1 Thoroughly mix the analysis sample of coal. Carefully
water for 15 min to allow cooling and absorption of soluble
weigh approximately 1g 6 0.1 mg into a previously ignited
vapors within the bomb.
crucible in which it is to be combusted.
8.5 Remove the bomb and release the pressure at a uniform
rate, such that the operation will require not less than 2 min.
NOTE 1—For samples in excess of 5% sulfur, the weight of coal must
Examine the bomb interior and discard the test if unburned or
be reduced to 0.5 6 0.1 g to ensure that all the acidic vapors produced in
sooty deposits are found.
the combustion process are quantitatively reta
...