ASTM D3179-89(2002)
(Test Method)Standard Test Methods for Nitrogen in the Analysis Sample of Coal and Coke
Standard Test Methods for Nitrogen in the Analysis Sample of Coal and Coke
SCOPE
1.1 These test methods cover the determination of total nitrogen in samples of coal and coke. The analytical data from these test methods shall be reported as part of ultimate analysis where ultimate analysis is requested. If ultimate analysis is not requested, the value shall be reported according to the request. Two methods are included as follows: SectionsTest Method A—Kjeldahl-Gunning Macro Analysis, with an alter-native technique included9 to 16Test Method B—Kjeldahl-Gunning Semi-Micro Determination 17 to 23
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.
1.2 The values stated in SI units are to be regarded as the standard.
General Information
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Standards Content (Sample)
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Designation: D 3179 – 89 (Reapproved 2002)
Standard Test Methods for
Nitrogen in the Analysis Sample of Coal and Coke
This standard is issued under the fixed designation D 3179; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope to Definitions D 121. For an explanation of the metric system
including units, symbols, and conversion factors, see IEEE/
1.1 These test methods cover the determination of total
ASTM SI 10.
nitrogen in samples of coal and coke. The analytical data from
these test methods shall be reported as part of ultimate analysis
4. Summary of Test Methods
where ultimate analysis is requested. If ultimate analysis is not
4.1 In these procedures, nitrogen is converted into ammo-
requested, the value shall be reported according to the request.
nium salts by destructive digestion of the sample with a hot,
Two methods are included as follows:
catalyzed mixture of concentrated sulfuric acid and potassium
Sections
sulfate. These salts are subsequently decomposed in a hot
Test Method A—Kjeldahl-Gunning Macro Analysis, with an alter-
native technique included 9 to 16
alkaline solution from which the ammonia is recovered by
Test Method B—Kjeldahl-Gunning Semi-Micro Determination 17 to 23
distillation and finally determined by alkalimetric or acidimet-
1.2 This standard does not purport to address all of the ric titration.
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 Nitrogen results obtained by these test methods are
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. required to fulfill the requirements of the ultimate analysis,
Practice D 3176. Also, results obtained may be used to evaluate
1.3 The values stated in SI units are to be regarded as the
standard. the potential formation of nitrogen oxides as a source of
atmospheric pollution.
2. Referenced Documents
5.2 Nitrogen data are used in comparing coals and in
2.1 ASTM Standards: research. When the oxygen content of coal is estimated by
D 121 Terminology of Coal and Coke difference, it is necessary to make a nitrogen determination.
D 346 Practice for Collection and Preparation of Coke
2 6. Interferences
Samples for Laboratory Analysis
D 1193 Specification for Reagent Water 6.1 No significant interferences have been determined using
D 2013 Practice for Preparing Coal Samples for Analysis these procedures. However, strict adherence is necessary when
D 3173 Test Method for Moisture in the Analysis Sample of using these nitrogen procedures to obtain good reproducible
Coal and Coke results.
D 3176 Practice for Ultimate Analysis of Coal and Coke
7. Reagents
D 3180 Practice for Calculating Coal and Coke Analyses
7.1 Purity of Reagents—Reagent grade chemicals shall be
from As-Determined to Different Bases
used in all tests. Unless otherwise indicated, it is intended that
IEEE/ASTM SI 10 Standard for Use of the International
all reagents shall conform to the specifications of the Commit-
System of Units (SI): The Modern Metric System
tee on Analytical Reagents of the American Chemical Society,
3. Terminology
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
3.1 For definitions of terms used in these test methods, refer
sufficient purity to meet its use without lessening the accuracy
of the determination.
These test methods are under the jurisdiction of ASTM Committee D05 on Coal
and Coke and are the direct responsibility of Subcommittee D05.21 on Methods of
Analysis.
Current edition approved Sept. 29, 1989. Published February 1990. Originally Reagent Chemicals, American Chemical Society Specifications, American
e1
published as D 3179 – 73. Last previous edition D 3179 – 89 (1997) . Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Annual Book of ASTM Standards, Vol 05.06. listed by the American Chemical Society, see Analar Standards for Laboratory
Annual Book of ASTM Standards, Vol 11.01. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Annual Book of ASTM Standards, Vol 14.02. Excerpts appear in the gray pages and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
of all the volumes. MD.
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 discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3179
7.2 Water—Unless otherwise indicated, references to water sium sulfide (K S) and 500 g of sodium hydroxide (NaOH)
shall be understood to mean Type II reagent water, conforming (Warning—This solution becomes very hot. Cool the solution
to Specification D 1193. and dilute to 1 L. The use of appropriate amounts of sodium
sulfide (Na S) or potassium hydroxide (KOH) may be substi-
8. Sampling and Preparation
tuted (Note 13).)
8.1 The sample shall be the material pulverized to pass No.
11.2 Ethyl Alcohol (95 %)—Ethyl alcohol conforming to
60 (250-μm) sieve and well mixed in accordance with Method
Formula No. 30 or 2A of the U.S. Bureau of Internal Revenue.
D 346 or Method D 2013. In the case of coke and anthracite,
Methyl alcohol may be used.
grinding the sample to pass a No. 200 (75-μm) or finer sieve is
11.3 Mercury.
recommended.
NOTE 1—Other satisfactory and permissible catalysts for the digestion,
8.2 A separate portion of the analysis sample should be
together with the quantities of K SO required in their use are as follows:
2 4
analyzed for moisture content in accordance with Test Method
(1) Five grams of a mixture containing 32 parts by weight of K SO ,5
2 4
D 3173, in order to allow calculation of the as-analyzed data to
parts by weight of mercuric sulfate (HgSO ), and one part by weight of
other bases.
selenium.
(2) Three-tenths gram of mercuric selenite (HgSeO )with7to10gof
TEST METHOD A—MACRO-NITROGEN
K SO .
2 4
DETERMINATION WITH ALTERNATIVE METHOD
(3) Three-tenths gram of cupric selenite dihydrate (CuSeO ·2H O)
3 2
INCLUDED
with7to10gofK SO . When this mixture is used, the addition of a
2 4
sulfide to the alkali solution is not necessary.
9. Scope and Application
11.4 Potassium Permanganate (KMnO ), crystals.
9.1 This test method describes a macro procedure for the
11.5 Potassium Sulfate (K SO ), crystals.
2 4
determination of nitrogen in both coal and coke, by two
11.6 Sucrose, National Institute of Standards and Technol-
alternative procedures. In both procedures,a1g sample is
ogy primary-standard grade.
digested with a hot catalyzed mixture of concentrated sulfuric
11.7 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
acid and potassium sulfate, which converts the nitrogenous
(H SO ).
2 4
compounds to ammonium salts. The salts are then decomposed
11.8 Zinc, mossy or granular.
in a hot alkaline solution, releasing the ammonia, which is then
distilled into either standard sulfuric-acid or boric-acid solution
REAGENTS REQUIRED ONLY FOR
and finally determined by alkalimetric or acidimetric titration.
KJELDAHL-GUNNING METHOD
10. Apparatus
11.9 Methyl Red Indicator Solution (0.4 to 1 g/L)—Dissolve
0.04 to 0.1 g of methyl red in 50 mL of 95 % ethyl alcohol or
10.1 Digestion Unit—An electrically heated digestion rack
methyl alcohol and add 50 mL of water. Bromcresol green
or a gas burner; either type of heater shall be provided with
solutions to equal concentrations may be used.
adequate means of control to maintain digestion rates as
11.10 Sodium Hydroxide, Standard Solution (0.1 to 0.2
described in 12.1. It is essential that an electric digestion rack
N)—Prepare and accurately standardize a 0.1 to 0.2 N sodium
provides adjustable controls to regulate desirable digestion
hydroxide (NaOH) solution against a primary standard.
temperatures. To eliminate emission of sulfur-acid fumes, the
11.11 Sulfuric Acid (0.2 N)—Prepare and standardize a 0.2
digestion process must be carried out under a well-ventilated
N sulfuric acid (H SO ) solution. The solution need not be
fume hood. Commercially made multiple-unit digestion racks
2 4
standardized against a primary standard.
provided with fume exhaust ducts may be used.
10.2 Digestion Flasks—Made of heat-resistant glass, hav-
REAGENTS REQUIRED ONLY FOR ALTERNATIVE
ing a capacity of 500 or 800 mL.
METHOD
10.3 Distillation Unit—A suitable glass steam distillation
11.12 Boric Acid Solution (50 g/L)—Dissolve5gof boric
unit with a splash head to trap any entrained caustic soda and
acid (H BO ) in 100 mL of boiling water. Allow to cool before
also provided with adequate means of control to maintain
3 3
use.
distillation rates as described in 12.1. Commercially made
11.13 Mixed Indicator Solution—Prepare a solution con-
multiple unit distillation racks provided with water-cooled
glass or block-tin condensers may be used. taining 0.125 % methyl red and 0.083 % methylene blue in
95 % ethyl alcohol or in methyl alcohol. Prepare a fresh
10.4 Buret—Microburet graduated in 0.01 mL. A50 mL
microburet is needed for Method A. solution at bimonthly intervals.
11.14 Sulfuric Acid (0.1 to 0.2 N)—Prepare and accurately
10.5 Erlenmeyer Flask—Having a capacity of 250 to 300
mL. standardize a 0.1 to 0.2 N sulfuric acid (H SO ) solution
2 4
against a primary standard; hydrochloric acid (HCl) of similar
10.6 Rubber Tubing—Sufficient for attaching condenser to
cooling water supply and drain. concentration may be substituted.
10.7 Pipets—As required.
12. Procedure
11. Reagents
12.1 Weigh approximately 1 g (weighed to nearest 1 mg) of
11.1 Alkali Solution—Cautiously dissolve 8.0 g of potas-
the analysis sample and carefully transfer into a 500 or 800-mL
Kjeldahl flask containing 7 to 10 g of K SO and 0.6 to 0.8 of
2 4
Borosilicate glass has been found satisfactory for this purpose. mercury (Note 1). Add 30 mL of H SO (sp gr 1.84) to the
2 4
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3179
mixture by pouring down the neck of the flask with rotation, in 13. Calculation and Report
order to wash any adherent sample material into the mixture.
13.1 Calculate the percentage of nitrogen in the analysis
Swirl the contents of the flask several times to ensure thorough
sample as follows:
mixing and wetting of the sample. Incline the flask at an angle
Nitrogen, % 5 @~B 2 A!N 3 0.014/C# 3 100 (1)
of 45 to 60° on the digestion heater in a fume hood (Note 2),
and heat the contents to boiling; controlling the heat so the
where:
H SO vapors condense no more than halfway up the neck of A = millilitres of NaOH solution required for titration of
2 4
the sample,
the flask. Continue the boiling until all sample particles are
B = millilitres of NaOH solution required for titration of
oxidized, as evidenced by a nearly colorless solution, or for at
the blank,
least 2 h after the solution has reached a straw-colored stage.
N = normality of the NaOH solution, and
The total time of digestion will require 3 to 6 h, except in the
C = grams of sample used.
case of coke and anthracite, which may require 12 to 16 h
(Note 3). When the digestion is completed and the solution has
14. Procedure for Alternative Technique
cooled, a few crystals of KMnO may be added to ensure
14.1 Digest the sample as described in 12.1.
complete oxidation; further heating may be necessary to
14.2 Dilute and cool the digestion mixture as described in
destroy the excess permanganate and decolorize the solution.
12.2. Add to the 250 or 300-mL Erlenmeyer flask approxi-
NOTE 2—When fume exhaust ducts or hoods are not available, a mately 20 mL of H BO solution and 5 drops of mixed
3 3
Hengar tube may be inserted in the neck of the flask.
indicator solution. Then proceed as described in the remainder
NOTE 3—Addition of 0.1 g of chromic trioxide (CrO ) to the digestion of 12.2.
mixture has been found very helpful in reducing the time of digestion for
14.3 Distill the ammonia into the H BO solution exactly as
3 3
coke.
described in 12.3 and finally titrate the ammonia with 0.2 N
H SO .
2 4
12.2 Dilute the cooled digestion mixture to about 300 mL
14.4 Run a blank determination in the same manner as
with cold water, and remove any heat of dilution by cooling
described in 14.1-14.3, using approximately 1 g (weighed to
with water. Meanwhile, pipet into the 250 or 300-mL Erlenm-
the nearest 1 mg) of sucrose as the sample material. Blank
eyer flask, 20.0 mL of 0.2 N H SO and add 6 drops of methyl
2 4
determinations must be made to correct for nitrogen from
red or bromcresol green indicator solution. Attach the glass
sources other than the sample. A blank determination shall be
connecting tube to the discharge end of the condenser, using
made whenever a new batch of any one reagent is used in the
the short piece of rubber tubing as a seal. Incline the Erlenm-
analysis.
eyer flask at a suitable angle, and insert this tube so that the end
14.5 Calculation—Calculate the percentage of nitrogen in
is immersed to the maximum depth in the acid. Add 1 to2gof
the sample as follows:
granular zinc to the mixture in the Kjeldahl flask (two or three
Nitrogen, %, in the analysis sample
small pieces of mossy zinc is used), and slowly add 100 mL of
the alkali solution so that it forms a distinct layer under the acid
5 @~A 2 B!N 3 0.014/C# 3 100
solution. (Warning—If the layers are mixed, considerable heat
(2)
may be generated with subsequent spray of the flask contents.
where:
The flask opening should be directed away from the operator
A = millilitres of H SO required for titration of the
2 4
and others during this step.) This may be accomplished by
sample,
inclining the flask at an angle of 45 to 60° and pouring the
B = millilitres of H SO required for titration of the blank,
2 4
alkali solution down the neck. Failure to maintain discrete
N = normality of the H SO , and
2 4
layers during this operation may lead to loss of ammonia.
C = grams of the sample used.
Quickly connect the flask to the distilling condenser through
the Kjeldahl connecting bulb, and then swirl the contents to
15. Report
promote thorough mixing.
15.1 The results of the nitrogen analysis may be reported on
12.3 Bring the contents of the Kjeldahl flask to a boil
any of a number of bases, differing from
...
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