ASTM D7582-24

Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis

SIGNIFICANCE AND USE
5.1 Moisture, as determined by this instrumental test method, is used for calculating other analytical results to a dry basis using procedures in Practice D3180.  
5.2 Moisture can be used in conjunction with the air-dry moisture loss determined by Test Method D3302 to determine total moisture in coal. Total moisture is used for calculating other analytical results to an as-received basis using Practice D3180.  
5.3 Ash yield is the residue remaining after heating the coal and coke samples (see Note 1).
Note 1: The ash obtained differs in composition and amount from the mineral constituents present in the original coal. Combustion causes an expulsion of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrite into iron oxides and sulfur oxides, and other chemical reactions. Ash yield, as determined by this test method, can differ from the amount of ash produced in furnace operations or other combustion systems because combustion conditions influence the chemistry and amount of ash.  
5.4 Ash yield is used, (1) as a parameter for evaluating sampling procedures and coal cleaning processes,  (2) in the ultimate analysis calculation of oxygen by difference using Practice D3176, (3) in calculations including material balance, reactivity and yields of products relevant to coal conversion processes such as gasification and liquefaction, (4)  in calculations to estimate the loading on electrostatic precipitators and on the fly ash and bottom ash disposal systems as well as erosion rates on boiler systems.  
5.5 Volatile matter yield, when determined as herein described, may be used to (1) indicate coke yield on carbonization, (2) provide the basis for purchasing and selling, or (3) establish combustion characteristics.  
5.6 Fixed carbon is a calculated value. It is the difference between 100 % and the sum of the mass fractions, in %, of moisture, ash, and volatile matter. All mass fractions shall be on the same moisture reference base.  
...
SCOPE
1.1 These instrumental test methods cover the determination of moisture, volatile matter, and ash, and the calculation of fixed carbon in the analysis of coal and coke samples prepared in accordance with Practice D2013 and Practice D346.  
1.2 These instrumental test methods are not applicable to thermogravimetric analyzers using microgram size samples.  
1.3 Test Methods D3173, D3174, and D3175 shall be considered the referee test methods.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 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.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2024
• ICS: 73.040 - Coals
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.21 - Methods of Analysis

Relations

• Replaces: ASTM D7582-15(2023) - Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis
• Effective Date: 01-Apr-2024
• Refers: ASTM D3176-24 - Standard Practice for Ultimate Analysis of Coal and Coke
• Effective Date: 01-Apr-2024
• Refers: ASTM D3176-15(2023) - Standard Practice for Ultimate Analysis of Coal and Coke
• Effective Date: 01-Dec-2023
• Referred By: ASTM D6357-21b - Standard Test Methods for Determination of Trace Elements in Coal, Coke, and Combustion Residues from Coal Utilization Processes by Inductively Coupled Plasma Atomic Emission Spectrometry, Inductively Coupled Plasma Mass Spectrometry, and Graphite Furnace Atomic Absorption Spectrometry
• Effective Date: 01-Apr-2024
• Referred By: ASTM D8247-19 - Standard Test Method for Determination of Total Fluorine and Total Chlorine in Coal by Oxidative Pyrohydrolytic Combustion Followed by Ion Chromatography Detection
• Effective Date: 01-Apr-2024
• Referred By: ASTM D3175-20 - Standard Test Method for Volatile Matter in the Analysis Sample of Coal and Coke
• Effective Date: 01-Apr-2024
• Referred By: ASTM D3180-15(2023) - Standard Practice for Calculating Coal and Coke Analyses from As-Determined to Different Bases
• Effective Date: 01-Apr-2024
• Referred By: ASTM D6349-21 - Standard Test Method for Determination of Major and Minor Elements in Coal, Coke, and Solid Residues from Combustion of Coal and Coke by Inductively Coupled Plasma-Atomic Emission Spectrometry
• Effective Date: 01-Apr-2024
• Referred By: ASTM D2013/D2013M-21 - Standard Practice for Preparing Coal Samples for Analysis
• Effective Date: 01-Apr-2024
• Referred By: ASTM D7348-21 - Standard Test Methods for Loss on Ignition (LOI) of Solid Combustion Residues
• Effective Date: 01-Apr-2024
• Referred By: ASTM D8010-18 - Standard Test Method for Determination of Water Soluble Alkali Content in Coal
• Effective Date: 01-Apr-2024
• Referred By: ASTM D5373-21 - Standard Test Methods for Determination of Carbon, Hydrogen and Nitrogen in Analysis Samples of Coal and Carbon in Analysis Samples of Coal and Coke
• Effective Date: 01-Apr-2024
• Referred By: ASTM D5865/D5865M-19 - Standard Test Method for Gross Calorific Value of Coal and Coke
• Effective Date: 01-Apr-2024
• Referred By: ASTM D6796-21e1 - Standard Practice for Production of Coal, Coke and Coal Combustion Samples for Interlaboratory Studies
• Effective Date: 01-Apr-2024
• Referred By: ASTM D2866-11(2018) - Standard Test Method for Total Ash Content of Activated Carbon
• Effective Date: 01-Apr-2024

Overview

ASTM D7582-24: Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis specifies instrumental test procedures to determine moisture, volatile matter, and ash, and to calculate fixed carbon in coal and coke. This standard is essential for laboratories involved in coal quality assessment, blending, trading, and process optimization in power generation and metallurgical industries.

The macro thermogravimetric analysis (macro-TGA) described offers automated, precise, and sequential measurement of key coal and coke characteristics using furnace-based sample mass tracking, making it a preferred method for both research and industrial laboratories.

Key Topics

• Proximate Analysis Parameters: Determines the mass fraction of moisture, volatile matter, and ash in coal and coke samples, and calculates the fixed carbon by difference. These are foundational metrics for coal and coke testing.
• Macro Thermogravimetric Analysis (TGA): Utilizes a macro-TGA instrument to monitor mass loss of a sample during controlled heating.
• Moisture Determination: Results are used for recalculating other analytical outcomes to various bases (e.g., dry, as-received).
• Ash Yield: Ash content is used to evaluate sampling and cleaning procedures, ultimate analysis, and process calculations relevant to combustion and conversion.
• Volatile Matter Measurement: Key for indicating coke yield, supporting combustion analysis, and determining purchase criteria.
• Fixed Carbon: Calculated as the remainder after subtracting measured moisture, volatile matter, and ash percentages.
• Precision and Repeatability: Evaluated following ASTM protocols, ensuring reliable, reproducible testing across laboratories.
• Safety and Calibration: Emphasizes the need for appropriate safety practices and regular calibration using certified reference materials.

Applications

The standardized methods in ASTM D7582-24 are widely applicable across:

• Coal and Coke Quality Control: Routine proximate analysis in mining, utilities, steel production, and coke manufacturing to monitor and control feedstock quality.
• Process Optimization: Input data for power plant and industrial boiler operations, helping adjust airflows, fuel blending, and combustion systems for efficiency and emissions control.
• Contractual Analysis: Ensures quality compliance for coal and coke trading by providing bases for pricing and specification.
• Coal Blending & Cleaning Plants: Assists in monitoring beneficiation effectiveness and adjusting processing strategies.
• Environmental Compliance: Data on ash and sulfur are used to calculate emissions and plan for fly ash/bottom ash disposal.
• Research & Development: Offers a standard approach for laboratory studies in fuel research and material characterization.

Related Standards

Users of ASTM D7582-24 often reference these related ASTM standards for fully compliant proximate and ultimate analysis:

• ASTM D2013 – Practice for Preparing Coal Samples for Analysis
• ASTM D346 – Practice for Collection and Preparation of Coke Samples for Laboratory Analysis
• ASTM D3173 – Test Method for Moisture in the Analysis Sample of Coal and Coke
• ASTM D3174 – Test Method for Ash in the Analysis Sample of Coal and Coke from Coal
• ASTM D3175 – Test Method for Volatile Matter in the Analysis Sample of Coal and Coke
• ASTM D3176 – Practice for Ultimate Analysis of Coal and Coke
• ASTM D3180 – Practice for Calculating Coal and Coke Analyses from As-Determined to Different Bases
• ASTM D3302 – Test Method for Total Moisture in Coal

Employing ASTM D7582-24 alongside these references enables standardized, internationally recognized reporting of coal and coke properties, supporting consistency, accuracy, and comparability across commercial and technical operations in the energy and metallurgical sectors.

Keywords: ASTM D7582-24, proximate analysis, coal analysis, coke analysis, macro thermogravimetric analysis, moisture, ash content, volatile matter, fixed carbon, coal testing, coke testing, quality control.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7582 − 24
Standard Test Methods for
Proximate Analysis of Coal and Coke by Macro
Thermogravimetric Analysis
This standard is issued under the fixed designation D7582; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D3174 Test Method for Ash in the Analysis Sample of Coal
and Coke from Coal
1.1 These instrumental test methods cover the determination
D3175 Test Method for Volatile Matter in the Analysis
of moisture, volatile matter, and ash, and the calculation of
Sample of Coal and Coke
fixed carbon in the analysis of coal and coke samples prepared
D3176 Practice for Ultimate Analysis of Coal and Coke
in accordance with Practice D2013 and Practice D346.
D3180 Practice for Calculating Coal and Coke Analyses
1.2 These instrumental test methods are not applicable to
from As-Determined to Different Bases
thermogravimetric analyzers using microgram size samples.
D3302 Test Method for Total Moisture in Coal
1.3 Test Methods D3173, D3174, and D3175 shall be D5016 Test Method for Total Sulfur in Coal and Coke
Combustion Residues Using a High-Temperature Tube
considered the referee test methods.
Furnace Combustion Method with Infrared Absorption
1.4 The values stated in SI units are to be regarded as
E691 Practice for Conducting an Interlaboratory Study to
standard. The values given in parentheses after SI units are
Determine the Precision of a Test Method
provided for information only and are not considered standard.
1.5 This standard does not purport to address all of the 3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 For definitions of terms used in this test method, refer to
responsibility of the user of this standard to establish appro-
Terminology D121.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Test Method
1.6 This international standard was developed in accor-
4.1 In thermogravimetric analysis, the mass of a sample in
dance with internationally recognized principles on standard-
a controlled atmosphere is recorded repeatedly as a function of
ization established in the Decision on Principles for the
temperature or time, or both. In macro thermogravimetric
Development of International Standards, Guides and Recom-
analysis, a sample size of approximately 1 g is used. All mass
mendations issued by the World Trade Organization Technical
measurements are conducted by the system. In a typical
Barriers to Trade (TBT) Committee.
analysis, the temperature is normally ramped from ambient to
a specific temperature and held at that temperature for a
2. Referenced Documents
prescribed length of time. The mass change is recorded
2.1 ASTM Standards:
repeatedly during the entire procedure. For the thermogravi-
D121 Terminology of Coal and Coke
metric analysis of coal and coke samples the moisture and ash
D346 Practice for Collection and Preparation of Coke
analyses are complete when the sample reaches a constant
Samples for Laboratory Analysis
mass as defined in the instrumental operating parameters.
D2013 Practice for Preparing Coal Samples for Analysis
Alternatively, the measurement of moisture and ash can be
D3173 Test Method for Moisture in the Analysis Sample of
considered complete after heating the sample for a fixed period
Coal and Coke
of time. In the volatile matter analysis, the mass of the samples
is determined after heating to 950 °C and held at this tempera-
This test method is under the jurisdiction of ASTM Committee D05 on Coal
ture for 7 min.
and Coke and is the direct responsibility of Subcommittee D05.21 on Methods of
Analysis.
4.2 Moisture is determined by measuring the loss in mass of
Current edition approved April 1, 2024. Published April 2024. Originally
the analysis specimen of coal or coke when heated under
approved in 2009. Last previous edition approved in 2023 as D7582 – 15 (2023).
specified conditions of temperature, time, atmosphere, speci-
DOI: 10.1520/D7582-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or men mass, and equipment specifications.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.3 Volatile matter is determined by measuring the loss in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. mass of the analysis specimen of coal or coke when heated
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7582 − 24
under rigidly controlled conditions. The measured mass loss is 5.4 Ash yield is used, (1) as a parameter for evaluating
used to calculate the volatile matter after correcting for the sampling procedures and coal cleaning processes, (2) in the
moisture level. ultimate analysis calculation of oxygen by difference using
Practice D3176, (3) in calculations including material balance,
4.4 Ash is determined by measuring the mass of the residue
reactivity and yields of products relevant to coal conversion
remaining after burning the coal or coke specimen under
processes such as gasification and liquefaction, (4) in calcula-
specified conditions of specimen mass, temperature, time,
tions to estimate the loading on electrostatic precipitators and
atmosphere, and equipment specifications.
on the fly ash and bottom ash disposal systems as well as
4.5 In these test methods, moisture, volatile matter, and ash
erosion rates on boiler systems.
can be determined sequentially in a single instrumental proce-
5.5 Volatile matter yield, when determined as herein
dure. Another procedure allows the moisture and ash to be
described, may be used to (1) indicate coke yield on
determined sequentially. Moisture and ash can also be deter-
carbonization, (2) provide the basis for purchasing and selling,
mined in separate determinations. Ruggedness testing and past
or (3) establish combustion characteristics.
experiences have shown the volatile matter values determined
on samples without first determining the moisture (drying the 5.6 Fixed carbon is a calculated value. It is the difference
sample) are always higher than those of the dried samples. between 100 % and the sum of the mass fractions, in %, of
moisture, ash, and volatile matter. All mass fractions shall be
4.6 Good laboratory practice requires checking for biases
on the same moisture reference base.
between analytical methods for contractual compliance. When
only a few coal types will be routinely tested, the instrument 5.7 Moisture, ash, and volatile matter are three of the
used in these test methods must be shown to yield results, for principal parameters used for assessing the quality of coal.
the coal(s) to be tested, that are equivalent to those obtained
6. Interferences
using Test Methods D3173, D3174, and D3175. If they are
found to be not equivalent, either the instrument used is
6.1 There are no known interferences for these test methods.
calibrated or the instrumental results are adjusted to establish
and maintain equivalence. Alternatively, when a broad spec- 7. Apparatus
trum of coal types will be tested, the instrument used in these
7.1 Macro Thermogravimetric Analyzer (Macro TGA)—A
test methods shall be calibrated using certified reference
computer controlled apparatus consisting of a furnace with a
materials of known composition covering the range of param-
cavity large enough to accept crucibles containing test speci-
eters being determined. The certified values shall be estab-
mens that meet the minimum mass requirements of the
lished using Test Methods D3173, D3174, and D3175. Section
procedure. The macro TGA system can accommodate multiple
16.2 lists a number of biases that have been shown to exist
crucibles, allowing for continuous analysis with one crucible
between instrumental results. Other biases, of unknown mag-
reserved for the blank or reference crucible. The furnace is
nitude and sign, may exist for other coals.
constructed so the cavity is surrounded by a suitable refractory
and insulated so as to develop a uniform temperature in all
5. Significance and Use
parts of the cavity, but with a minimum free space. The furnace
5.1 Moisture, as determined by this instrumental test shall be capable of being heated rapidly 30 °C ⁄min to
45 °C ⁄min from ambient temperature to 950 °C. The tempera-
method, is used for calculating other analytical results to a dry
basis using procedures in Practice D3180. ture shall be monitored and maintained at values specified for
each determination. The system shall have an integrated
5.2 Moisture can be used in conjunction with the air-dry
balance capable of determining the crucibles and test speci-
moisture loss determined by Test Method D3302 to determine
mens masses repeatedly throughout the analysis. All mass
total moisture in coal. Total moisture is used for calculating
measurements are conducted and recorded by the system. The
other analytical results to an as-received basis using Practice
sensitivity of the balance shall be at least 0.1 mg. Provision
D3180.
shall be made to introduce gases specified for this standard and
5.3 Ash yield is the residue remaining after heating the coal
to remove products of drying, devolatilization, and combus-
and coke samples (see Note 1).
tion. The macro TGA system shall have a venting fan, tolerant
of hot product gases, to efficiently remove the exhaust gases.
NOTE 1—The ash obtained differs in composition and amount from the
mineral constituents present in the original coal. Combustion causes an
7.2 Crucibles—with covers of composition and dimensions
expulsion of all water, the loss of carbon dioxide from carbonates, the
specified for the instrument by the instrument manufacturer.
conversion of iron pyrite into iron oxides and sulfur oxides, and other
The covers shall fit closely enough so that the carbon deposit
chemical reactions. Ash yield, as determined by this test method, can
differ from the amount of ash produced in furnace operations or other
from bituminous, subbituminous, and lignitic coals does not
combustion systems because combustion conditions influence the chem-
burn away from the underside of the cover during the deter-
istry and amount of ash.
mination of the volatile matter
8. Reagents and Materials
Riley J.T., Yanes E.G, Marsh M., Lawrenz D., and Eichenbaum L., “Coal and
8.1 Drying Gas—Nitrogen (99.5 % purity), Argon (99.5 %
Coke Volatile Matter Determination and Reconciliation of Differences in Yields
purity) or air, dried to a moisture level of 1.9 mg ⁄L or less (dew
Determined by Two ASTM Methods,” J. Testing and Evaluation, 2010, 38(4),
458-466. point –10 °C or less).
D7582 − 24
8.2 Inert Gas—Nitrogen (99.5 % purity) or Argon (99.5 % The calibration shall be performed at the same furnace ramp
purity). temperature as that used for the analysis. Do not use coal
reference material(s) for coke volatile matter calibration. Do
8.3 Oxidizing Gas—Oxygen (99.5 % purity) or air.
not use coke reference material(s) for coal volatile matter
8.4 Certified Reference Materials—Coal or coke material(s)
calibration. Use coal reference material(s) with a certified
meeting the requirements of 10.1, with a certificate of analysis
reference value and uncertainty based on measurements made
specifying the reference value and the uncertainty of the
employing Test Methods D3173, D3174, and D3175 to cali-
reference value. Reference material(s) can be employed to
brate this test method.
calibrate the instrument for the determination of volatile
matter. Certified reference values shall have been established
13. Procedure
using Test Methods D3173, D3174, and D3175. Reference
13.1 The determination of moisture, followed by volatile
materials used for the calibration of volatile matter shall
matter followed by ash can be carried out in sequence using the
include information on the certificate of analysis detailing the
same test specimen. Alternatively, the determination of
method(s) employed to determine volatile matter of the refer-
moisture, volatile matter, or ash can be carried out separately
ence material.
on test specimens of coal or coke.
9. Hazards
13.2 Sequential Determination of Moisture, Volatile Matter
9.1 The user shall insure acceptable documented safety
and Ash:
procedures are in place for the handling of all reagents and test
13.2.1 After verifying instrument setup according to Section
materials and for the operation of laboratory equipment speci-
11 on the preparation of apparatus, load and tare the crucibles.
fied for these test methods.
Add approximately 1 g of coal or coke to the crucible in the
balance position and determine the mass immediately before
9.2 Venting Equipment—Install equipment in the vicinity of
advancing the next crucible. Transfer the test specimen from
the apparatus to vent combustion and volatile gases evolved
the sample bottle to the crucible quickly to minimize the
during the test procedures from the laboratory.
exposure of the test specimen to the atmosphere during the
10. Analysis Sample
initial mass determination process.
10.1 The analysis sample shall be the material pulverized to 13.2.2 For moisture determinations, heat the test specimens
pass a 250 μm (No. 60 US Standard mesh) sieve in accordance
with determined mass in crucibles without the covers at 107 °C
with Practice D2013 or Practice D346. 6 3 °C. Use a drying gas flow rate of [0.4 to 1.4] furnace
volume changes per minute (see 8.1). Program the instrument
11. Preparation of Apparatus
to terminate the test when the test specimens and crucibles
11.1 Verify the instrument can meet all specifications in the
have reached a constant mass (see 11.3). Alternatively, pro-
standard with respect to gas flows, heating rates, and balance
gram the instrument to allow for moisture determination by
sensitivity prior to use. Condition the instrument after initial
heating the test specimens for 1 h.
setup, or repairs, by conducting a run through a complete cycle
13.2.3 For volatile matter determinations following the
without samples.
moisture analysis, place covers on the crucibles in the TGA
carousel (the covers are placed automatically in some systems
11.2 Condition new crucibles and covers for use in these test
and manually in others). Program the instrument to redeter-
methods by heating under the same conditions of the test and
mine the masses of the crucibles, with specimens inside, and
cool before use.
covers in place before initiating the volatile matter part of the
11.3 The macro TGA system can be programmed to termi-
cycle.
nate the measurement process when the test specimens and
13.2.3.1 To provide an inert atmosphere, use nitrogen or
crucibles have reached a constant mass. Crucibles masses are
argon with a flow rate of [0.7 to 1.4] furnace volume changes
determined by the instrument at specified intervals. The analy-
per minute to sweep away the volatile components. Raise the
sis is complete when the sample reaches constant mass.
furnace temperature at a rate such that the temperature is raised
Constant mass is defined as a point where the mass change is
from 107 °C to 950 °C 6 20 °C in a 26 min to 30 min time
< 0.05 % over a nine-minute period, either by using not less
period (See Note 2). Program the instrument to hold at this
than three successive mass determinations or a fixed nine-
temperature for 7 min. The TGA determines the masses of the
minute period of successive mass determinations. This mass
covered crucibles at regular intervals while the temperature of
change of 0.05 % is equivalent to 0.0005 g for a 1.0000 g
the furnace is raised. The masses of the crucibles and covers at
sample. Alternately, the instrument can be programmed to
the end of the 7 min hold period are used in the calculation of
allow for moisture and ash determination by heating the test
the volatile matter.
specimens for the time periods, heating rates and soak tem-
peratures specified in Test Methods D3173 and D3174. The
NOTE 2—It is the nature of resistance furnaces to start heating slowly
with a gradual increase in heating rate until the furnace heating element
mass measured at the end of the time period is used for
controller reduces the power to moderate the heating rate. As a result, high
calculations.
furnace ramp rates are seldom ever uniform over the temperature range
selected. Selecting a heating time 26 min to 30 min with a high heating
12. Calibration and Standardization
ramp rate accomplishes the desired result, to duplicate the conditions
12.1 The instrument shall be calibrated for the determina-
(Macro TGA furnaces set at 30 °C ⁄min to 45 °C ⁄min ramp rate) that were
tion of volatile matter employing certified reference materials. used by the laboratories in the interlaboratory study. At the same time, it
D7582 − 24
allows the Macro TGA furnaces to moderate the heating rate enough to
the end of 1 h. If the oxidizing gas is oxygen, the flow rate is
avoid overshooting the selected high temperature of 950 °C.
set at [0.4 to 0.5] furnace volume changes per minute. If the
13.2.3.2 With strongly caking low-volatile and medium- oxidizing gas is air, the flow rate is set at [1.3 to 1.4] furnace
volatile bituminous coals, the coke button can burst as a result volume changes per minute. Continue to heat and determine
of the rapid liberation of volatile matter within the button. This the masses of the test specimens at the high temperature until
is designated as popping. Such popping can blow the lid off the they reach a constant mass (See 11.3). Alternatively, program
crucible and cause mechanical loss of the coked material. the instrument to allow for ash determination by heating the
When evidence of such popping is observed, reject the deter- test specimens for not less than 2 h for coal, and 3 h for coke,
mination and repeat the test with smaller test specimen sizes after reaching the final high temperature (750 °C or 950 °C). If
until popping is no longer evident. Also, some high swelling there is evidence of carbonaceous material in the ash reject the
coals can expand beyond the volume of the crucible such that determination and repeat the test (See 13.4.3.1).
they raise the crucible cover and stick to the underside of the
13.4.3.1 Gradual heating allows sulfur-bearing materials to
cover. This material can be lost when the crucible cover is
be oxidized and release sulfur dioxide before calcium carbon-
removed. For swelling coals examine the crucible covers as
ate (calcite) decomposes. Some samples can contain a high
they are removed. If carbonaceous material clings to the
amount of carbonate minerals or pyrite, or both. In these cases,
underside of the cover, reject the determination and repeat the
sulfur retained as sulfates can be highly variable between
test with smaller test specimen sizes until there is no evidence
duplicate runs. In such cases, the sulfate sulfur in the ash can
of carbonaceous material clinging to the underside of the cover. be determined in accordance with Test Method D5016 and
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7582 − 15 (Reapproved 2023) D7582 − 24
Standard Test Methods for
Proximate Analysis of Coal and Coke by Macro
Thermogravimetric Analysis
This standard is issued under the fixed designation D7582; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 These instrumental test methods cover the determination of moisture, volatile matter, and ash, and the calculation of fixed
carbon in the analysis of coal and coke samples prepared in accordance with Practice D2013 and Practice D346.
1.2 These instrumental test methods are not applicable to thermogravimetric analyzers using microgram size samples.
1.3 Test Methods D3173, D3174, and D3175 shall be considered the referee test methods.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this The values
given in parentheses after SI units are provided for information only and are not considered standard.
1.5 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.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D121 Terminology of Coal and Coke
D346 Practice for Collection and Preparation of Coke Samples for Laboratory Analysis
D2013 Practice for Preparing Coal Samples for Analysis
D3173 Test Method for Moisture in the Analysis Sample of Coal and Coke
D3174 Test Method for Ash in the Analysis Sample of Coal and Coke from Coal
D3175 Test Method for Volatile Matter in the Analysis Sample of Coal and Coke
D3176 Practice for Ultimate Analysis of Coal and Coke
D3180 Practice for Calculating Coal and Coke Analyses from As-Determined to Different Bases
D3302 Test Method for Total Moisture in Coal
This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.21 on Methods of Analysis.
Current edition approved Dec. 1, 2023April 1, 2024. Published December 2023April 2024. Originally approved in 2009. Last previous edition approved in 20152023 as
D7582 – 15.D7582 – 15 (2023). DOI: 10.1520/D7582-15R23.10.1520/D7582-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7582 − 24
D5016 Test Method for Total Sulfur in Coal and Coke Combustion Residues Using a High-Temperature Tube Furnace
Combustion Method with Infrared Absorption
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 For definitions of terms used in this test method, refer to Terminology D121.
4. Summary of Test Method
4.1 In thermogravimetric analysis, the mass of a sample in a controlled atmosphere is recorded repeatedly as a function of
temperature or time, or both. In macro thermogravimetric analysis, a sample size of approximately 1 g is used. All mass
measurements are conducted by the system. In a typical analysis, the temperature is normally ramped from ambient to a specific
temperature and held at that temperature for a prescribed length of time. The mass change is recorded repeatedly during the entire
procedure. For the thermogravimetric analysis of coal and coke samples the moisture and ash analyses are complete when the
sample reaches a constant mass as defined in the instrumental operating parameters. Alternatively, the measurement of moisture
and ash can be considered complete after heating the sample for a fixed period of time. In the volatile matter analysis, the samples
are weighedmass of the samples is determined after heating to 950 °C and held at this temperature for 7 min.
4.2 Moisture is determined by measuring the loss in mass of the analysis specimen of coal or coke when heated under specified
conditions of temperature, time, atmosphere, specimen mass, and equipment specifications.
4.3 Volatile matter is determined by measuring the loss in mass of the analysis specimen of coal or coke when heated under rigidly
controlled conditions. The measured mass loss is used to calculate the volatile matter after correcting for the moisture content.level.
4.4 Ash is determined by measuring the mass of the residue remaining after burning the coal or coke specimen under specified
conditions of specimen mass, temperature, time, atmosphere, and equipment specifications.
4.5 In these test methods, moisture, volatile matter, and ash can be determined sequentially in a single instrumental procedure.
Another procedure allows the moisture and ash to be determined sequentially. Moisture and ash can also be determined in separate
determinations. Ruggedness testing and past experiences have shown the volatile matter values determined on samples without first
determining the moisture (drying the sample) are always higher than those of the dried samples.
4.6 Good laboratory practice requires checking for biases between analytical methods for contractual compliance. When only a
few coal types will be routinely tested, the instrument used in these test methods must be shown to yield results, for the coal(s)
to be tested, that are equivalent to those obtained using Test Methods D3173, D3174, and D3175. If they are found to be not
equivalent, either the instrument used is calibrated or the instrumental results are adjusted to establish and maintain equivalence.
Alternatively, when a broad spectrum of coal types will be tested, the instrument used in these test methods shall be calibrated using
certified reference materials of known composition covering the range of parameters being determined. The certified values shall
be established using Test Methods D3173, D3174, and D3175. Section 16.2 lists a number of biases that have been shown to exist
between instrumental results. Other biases, of unknown magnitude and sign, may exist for other coals.
5. Significance and Use
5.1 Moisture, as determined by this instrumental test method, is used for calculating other analytical results to a dry basis using
procedures in Practice D3180.
5.2 Moisture can be used in conjunction with the air-dry moisture loss determined by Test Method D3302 to determine total
moisture in coal. Total moisture is used for calculating other analytical results to an as-received basis using Practice D3180.
5.3 Ash yield is the residue remaining after heating the coal and coke samples (see Note 1).
Riley J.T., Yanes E.G, Marsh M., Lawrenz D., and Eichenbaum L., “Coal and Coke Volatile Matter Determination and Reconciliation of Differences in Yields Determined
by Two ASTM Methods,” J. Testing and Evaluation, 2010, 38(4), 458-466.
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NOTE 1—The ash obtained differs in composition and amount from the mineral constituents present in the original coal. Combustion causes an expulsion
of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrite into iron oxides and sulfur oxides, and other chemical reactions.
Ash yield, as determined by this test method, can differ from the amount of ash produced in furnace operations or other combustion systems because
combustion conditions influence the chemistry and amount of ash.
5.4 Ash yield is used, (1) as a parameter for evaluating sampling procedures and coal cleaning processes, (2) in the ultimate
analysis calculation of oxygen by difference using Practice D3176, (3) in calculations including material balance, reactivity and
yields of products relevant to coal conversion processes such as gasification and liquefaction, (4) in calculations to estimate the
loading on electrostatic precipitators and on the fly ash and bottom ash disposal systems as well as erosion rates on boiler systems.
5.5 Volatile matter yield, when determined as herein described, may be used to (1) indicate coke yield on carbonization, (2)
provide the basis for purchasing and selling, or (3) establish combustion characteristics.
5.6 Fixed carbon is a calculated value. It is the difference between 100100 % and the sum of the percent mass fractions, in %, of
moisture, ash, and volatile matter. All percents mass fractions shall be on the same moisture reference base.
5.7 Moisture, ash, and volatile matter are three of the principal parameters used for assessing the quality of coal.
6. Interferences
6.1 There are no known interferences for these test methods.
7. Apparatus
7.1 Macro Thermogravimetric Analyzer (Macro TGA)—A computer controlled apparatus consisting of a furnace with a cavity
large enough to accept crucibles containing test specimens that meet the minimum mass requirements of the procedure. The macro
TGA system can accommodate multiple crucibles, allowing for continuous analysis with one crucible reserved for the blank or
reference crucible. The furnace is constructed so the cavity is surrounded by a suitable refractory and insulated so as to develop
a uniform temperature in all parts of the cavity, but with a minimum free space. The furnace shall be capable of being heated
rapidly (30 °C30 °C ⁄min to 45 °C ⁄min from ambient temperature to 950 °C. The temperature shall be monitored and maintained
at values specified for each determination. The system shall have an integrated balance capable of weighingdetermining the
crucibles and test specimens masses repeatedly throughout the analysis. All mass measurements are conducted and recorded by
the system. The sensitivity of the balance shall be at least 0.1 mg. Provision shall be made to introduce gases specified for this
standard and to remove products of drying, devolatilization, and combustion. The macro TGA system shall have a venting fan,
tolerant of hot product gases, to efficiently remove the exhaust gases.
7.2 Crucibles—with covers of composition and dimensions specified for the instrument by the instrument manufacturer. The
covers shall fit closely enough so that the carbon deposit from bituminous, subbituminous, and lignitic coals does not burn away
from the underside of the cover during the determination of the volatile matter
8. Reagents and Materials
8.1 Drying Gas—Nitrogen (99.5 % purity), Argon (99.5 % purity) or air, dried to a moisture content of 1.9level of 1.9 mg mg/L
⁄L or less (dew point –10 °C or less).
8.2 Inert Gas—Nitrogen (99.5 % purity) or Argon (99.5 % purity).
8.3 Oxidizing Gas—Oxygen (99.5 % purity) or air.
8.4 Certified Reference Materials—Coal or coke material(s) meeting the requirements of 10.1, with a certificate of analysis
specifying the reference value and the uncertainty of the reference value. Reference material(s) can be employed to calibrate the
instrument for the determination of volatile matter. Certified reference values shall have been established using Test Methods
D3173, D3174, and D3175. Reference materials used for the calibration of volatile matter shall include information on the
certificate of analysis detailing the method(s) employed to determine volatile matter of the reference material.
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9. Hazards
9.1 The user shall insure acceptable documented safety procedures are in place for the handling of all reagents and test materials
and for the operation of laboratory equipment specified for these test methods.
9.2 Venting Equipment—Install equipment in the vicinity of the apparatus to vent combustion and volatile gases evolved during
the test procedures from the laboratory.
10. Analysis Sample
10.1 The analysis sample shall be the material pulverized to pass a 250-μm (No. 60) 250 μm (No. 60 US Standard mesh) sieve
in accordance with Practice D2013 or Practice D346.
11. Preparation of Apparatus
11.1 Verify the instrument can meet all specifications in the standard with respect to gas flows, heating rates, and balance
sensitivity prior to use. Condition the instrument after initial setup, or repairs, by conducting a run through a complete cycle
without samples.
11.2 Condition new crucibles and covers for use in these test methods by heating under the same conditions of the test and cool
before use.
11.3 The macro TGA system can be programmed to terminate the measurement process when the test specimens and crucibles
have reached a constant mass. Crucibles masses are weigheddetermined by the instrument at specified intervals. The analysis is
complete when the sample reaches constant mass. Constant mass is defined as a point where the mass change is < or = to 0.05 %
< 0.05 % over a nine-minute period, either by using not less than three successive weighings mass determinations or a fixed
nine-minute period of successive weighings. mass determinations. This mass change of 0.05 % is equivalent to 0.0005 g for a
1.0000 g sample. Alternately, the instrument can be programmed to allow for moisture and ash determination by heating the test
specimens for the time periods, heating rates and soak temperatures specified in Test Methods D3173 and D3174. The mass
measured at the end of the time period is used for calculations.
12. Calibration and Standardization
12.1 The instrument shall be calibrated for the determination of volatile matter employing certified reference materials. The
calibration shall be performed at the same furnace ramp temperature as that used for the analysis. Do not use coal reference
material(s) for coke volatile matter calibration. Do not use coke reference material(s) for coal volatile matter calibration. Use coal
reference material(s) with a certified reference value and uncertainty based on measurements made employing Test Methods
D3173, D3174, and D3175 to calibrate this test method.
13. Procedure
13.1 The determination of moisture, followed by volatile matter followed by ash can be carried out in sequence using the same
test specimen. Alternatively, the determination of moisture, volatile matter, or ash can be carried out separately on test specimens
of coal or coke.
13.2 Sequential Determination of Moisture, Volatile Matter and Ash:
13.2.1 After verifying instrument setup according to Section 11 on the preparation of apparatus, load and tare the crucibles. Add
approximately 1 g of coal or coke to the crucible in the balance position and weigh determine the mass immediately before
advancing the next crucible. Transfer the test specimen from the sample bottle to the crucible quickly to minimize the exposure
of the test specimen to the atmosphere during the initial weighing mass determination process.
13.2.2 For moisture determinations, heat the weighed test specimens with determined mass in crucibles without the covers at
107 °C 6 3 °C. Use a drying gas flow rate of 0.4 to 1.4[0.4 to 1.4] furnace volume changes per minute (see 8.1). Program the
instrument to terminate the test when the test specimens and crucibles have reached a constant mass (see 11.3). Alternatively,
program the instrument to allow for moisture determination by heating the test specimens for 1 h.
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13.2.3 For volatile matter determinations following the moisture analysis, place covers on the crucibles in the TGA carousel (the
covers are placed automatically in some systems and manually in others). Program the instrument to reweigh the redetermine the
masses of the crucibles, with specimens inside, and covers in place before initiating the volatile matter part of the cycle.
13.2.3.1 To provide an inert atmosphere, use nitrogen or argon with a flow rate of 0.7 to 1.4[0.7 to 1.4] furnace volume changes
per minute to sweep away the volatile components. Raise the furnace temperature at a rate such that the temperature is raised from
107 °C to 950 °C 6 20 °C in a 26 min to 30 min time period (See Note 2). Program the instrument to hold at this temperature for
7 min. The TGA weighs the determines the masses of the covered crucibles at regular intervals while the temperature of the furnace
is raised. The weightsmasses of the crucibles and covers at the end of the 7-min7 min hold period are used in the calculation of
the volatile matter.
NOTE 2—It is the nature of resistance furnaces to start heating slowly with a gradual increase in heating rate until the furnace heating element controller
reduces the power to moderate the heating rate. As a result, high furnace ramp rates are seldom ever uniform over the temperature range selected. Selecting
a heating time (26 min to 30 min)26 min to 30 min with a high heating ramp rate accomplishes the desired result, to duplicate the conditions (Macro TGA
furnaces set at 30 °C ⁄min to 45 °C ⁄min ramp rate) that were used by the laboratories in the interlaboratory study. At the same time, it allows the Macro
TGA furnaces to moderate the heating rate enough to avoid overshooting the selected high temperature of 950 °C.
13.2.3.2 With strongly caking low-volatile and medium-volatile bituminous coals, the coke button can burst as a result of the rapid
liberation of volatile matter within the button. This is designated as popping. Such popping can blow the lid off the crucible and
cause mechanical loss of the coked material. When evidence of such popping is observed, reject the determination and repeat the
test with smaller test specimen sizes until popping is no longer evident. Also, some high swelling coals can expand beyond the
volume of the crucible such that they raise the crucible cover and stick to the underside of the cover. This material can be lost when
the crucible cover is removed. For swelling coals examine the crucible covers as they are removed. If carbonaceous material clings
to the underside of the cover, reject the determination and repeat the test with smaller test specimen sizes until there is no evidence
of carbonaceous material clinging to the underside of the cover.
13.2.4 For ash determinations following the volatile matter determinations program the furnace to cool from 950 °C to 600 °C.
Remove the crucible covers. (The crucible covers are removed automatically in some systems and manually in others). Change
the furnace atmosphere to oxygen or air. For coals, raise the temperature at such a rate that a final temperature of 750 °C 6 15 °C
is reached at the end of 1 h. For cokes, raise the temperature at such a rate that a final temperature of 950 °C 6 20 °C is reached
at the end of 1 h. If the oxidizing gas is oxygen, adjust the flow rate to 0.4 to 0.5[0.4 to 0.5] furnace volume changes per minute.
If the oxidizing gas is air, adjust the flow rate to 1.3 to 1.4[1.3 to 1.4] furnace volume changes per minute. Program the instrument
to terminate the test when the test specimens and crucibles have reached a constant weightmass (See 11.3). Alternatively, program
the instrument to allow for ash determination by heating the test specimens for not less than 2 h for coal, and 3 h for coke, after
reaching the final hold temperature. If there is evidence of carbonaceous material in the ash, reject the determination and repeat
the test.
13.3 Sequential Determination of Moisture and Volatile Matter:
13.3.1 Follow the instructions in 13.2.1 to set up the instrument.
13.3.2 Follow the instructions in 13.2.2 for moisture dete
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