ASTM D7348-07
(Test Method)Standard Test Methods for Loss on Ignition (LOI) of Solid Combustion Residues
Standard Test Methods for Loss on Ignition (LOI) of Solid Combustion Residues
SCOPE
1.1 These test methods cover the determination of the mass loss from solid combustion residues upon heating in an air or oxygen atmosphere to a prescribed temperature. The mass loss can be due to the loss of moisture, carbon, sulfur, and so forth, from the decomposition or combustion of the residue.
1.2 The values given in SI units are to be considered as the standard.
1.3 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.
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Designation: D 7348 – 07
Standard Test Methods for
Loss on Ignition (LOI) of Solid Combustion Residues
This standard is issued under the fixed designation D 7348; 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 D 6357 Test Methods for Determination of Trace Elements
in Coal, Coke, and Combustion Residues from Coal
1.1 These test methods cover the determination of the mass
Utilization Processes by Inductively Coupled Plasma
loss from solid combustion residues upon heating in an air or
Atomic Emission Spectrometry, Inductively Coupled
oxygen atmosphere to a prescribed temperature. The mass loss
Plasma Mass Spectrometry, and Graphite Furnace Atomic
can be due to the loss of moisture, carbon, sulfur, and so forth,
Ab
from the decomposition or combustion of the residue.
1.2 The values given in SI units are to be considered as the
3. Terminology
standard.
3.1 Definitions—For definitions of terms used in these test
1.3 This standard does not purport to address all of the
methods, refer to Terminology D 121.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
4.1 Loss on ignition (LOI) is determined by measuring the
bility of regulatory limitations prior to use.
loss in mass of the test specimen when heated under controlled
2. Referenced Documents conditions of temperature, time, atmosphere, specimen mass,
2 and equipment specifications. The LOI can be determined by
2.1 ASTM Standards:
measuring the mass loss in a single procedure or in a two-step
D 121 Terminology of Coal and Coke
procedure in which mass losses, equivalent to the moisture and
D 3174 TestMethodforAshintheAnalysisSampleofCoal
ash values of the test specimen, are determined.
and Coke from Coal
D 3180 Practice for Calculating Coal and Coke Analyses
5. Significance and Use
from As-Determined to Different Bases
5.1 LOI refers to the mass loss of a combustion residue
D 3682 Test Method for Major and Minor Elements in
when it is heated in an air or oxygen atmosphere to high
Combustion Residues from Coal Utilization Processes
temperatures. In the cement industry, use of the term LOI
D 3683 Test Method for Trace Elements in Coal and Coke
normally refers to a mass loss in a sample heated to 950°C. To
Ash by Atomic Absorption
combustion engineers, the term LOI normally refers to mass
D 4326 Test Method for Major and Minor Elements in Coal
losses in samples heated to temperatures normally less than
and Coke Ash By X-Ray Fluorescence
950°C. These test methods establish a procedure for determin-
D 5142 Test Methods for Proximate Analysis of the Analy-
ing LOI values for combustion residues heated to 950°C. LOI
sis Sample of Coal and Coke by Instrumental Procedures
values from these test methods can be used by industries that
D 6316 Test Method for Determination of Total, Combus-
utilize combustion residues in various processes and products.
tible and Carbonate Carbon in Solid Residues from Coal
5.2 If the solid combustion residue is heated to estimate the
and Coke
combustible or unburned carbon in the sample, it has been
D 6349 Test Method for Determination of Major and Minor
shown that LOI and estimation of unburned carbon do not
Elements in Coal, Coke, and Solid Residues from Com-
necessarily agree well with each other and that LOI should not
bustion of Coal and Coke by Inductively Coupled
be used as an estimate of unburned carbon in all combustion
Plasma—Atomic Emission Spectrometry
residues. . Direct determination of unburned (combustible)
carbon can be carried out using Test Method D 6316.
5.3 If the solid combustion residue is heated to prepare an
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD05onCoal
ash for the determination of the concentrations of major and
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
Elements in Ash and Trace Elements of Coal.
Current edition approved May 1, 2007. Published May 2007.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contactASTM Customer Service as service@astm.org. ForAnnual Book ofASTM S.C. Burris, D. Li, and J.T.Riley, “Comparison of Heating Losses and Macro
Standards volume information, refer to the standard’s Document Summary page on Thermogravimetric Analysis Procedures for Estimating Unburned Carbon in Com-
the ASTM website. bustion Residues,” Energy Fuels, Vol 19, 2005, pp. 1493-1502.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7348–07
minor elements, use the heating procedure described in Test 7.5 Operation of the instrumental system in its entirety shall
Methods D 3682, D 4326, and D 6349. be verified in accordance with the manufacturer’s operating
instructions.
5.4 If the solid combustion residue is heated to prepare an
ash for the determination of the concentrations of trace 7.6 Venting Equipment—Combustion and decomposition
gases evolved during the test procedures shall be vented from
elements, use the heating procedure described in Test Methods
D 3683 and D 6357. thelaboratoryandsuitableventingequipmentshallbeinstalled
in the vicinity of the apparatus.
NOTE 1—Combustion residues produced in furnace operations or other
combustion systems can differ from the ash yield, as determined in Test
8. Reagents and Materials
Methods D 3174 and D 5142, because combustion conditions influence
8.1 Drying Gases—Air dried to a moisture content of 1.9
the chemistry and amount of ash. Combustion causes an expulsion of all
water, the loss of carbon dioxide from carbonates, the conversion of metal mg/L or less (dew point –10°C or less). Nitrogen (99.5 %
sulfides into metal oxides, metal sulfates and sulfur oxides, and other
purity) is normally used with the macro TGA system. Argon
chemicalreactions.Likewise,the“ash”obtainedafterignitingcombustion
can also be used.
residues can differ in composition and amount from Test Methods D 3174
8.2 Oxidizing Gases—Oxygen (99.5 % purity) or air.
and D 5142 ash yields because of different heating procedures, combus-
tion of unburned carbon, and decomposition of materials in the residue.
9. Hazards
9.1 The user shall insure acceptable documented safety
6. Interferences
procedures are in place for the handling of all reagents and test
6.1 Therearenoknowninterferencesforthesetestmethods.
materials and for the operation of laboratory equipment speci-
fied for these test methods.
7. Apparatus
10. Sampling, Test Specimens, and Test Units
7.1 Furnace—The apparatus shall consist of a furnace with
a cavity large enough to accept multiple crucibles. The furnace
10.1 The sample used for analysis shall be thoroughly
shall be constructed so the cavity is surrounded by a suitable
mixed and of such fineness to pass through a 250-µm (No. 60)
refractoryandinsulatedsoastodevelopauniformtemperature
sieve. Pulverizing the sample to this fineness is required.
in all parts of the cavity but with a minimum free space. The
11. Preparation of Apparatus
furnace shall be capable of being heated rapidly (10°C/min or
faster) from ambient to 950°C. The temperature shall be
11.1 ForLOIdeterminationsusingamacroTGA,followthe
monitored and maintained at values specific to each of the
manufacturer’s recommended procedure for verifying system
determinations. Provisions shall be made to introduce drying
stability and for loading and taring the crucibles. Various
and oxidizing gases and to remove products of drying, decom-
modes of operation are possible depending on the instrument
position, and combustion. A recommended flow rate is one
used and the manner in which the determinations are com-
furnace volume change per minute, but higher flow rates (that
pleted.Theinstrumentcanbeprogrammedtoterminatethetest
is, two furnace volumes per minute as in some other standard
when the test specimens and crucibles have reached a constant
testmethodsforcoalandcoke)areacceptable.Thefurnacecan
weight. Typically, crucibles are weighed automatically at
be a stand alone muffle furnace or a computer-controlled
specified intervals, and the analysis is complete when two
macrothermogravimetric analyzer (macro TGA) system. In
successiveweighingsagreewithinaplateaudeviationspecified
macroTGA,asamplesizeof1g(orlarger)isused.Inatypical
for the instrument. Alternately, the instrument can be pro-
analysis, the temperature is ramped from ambient to a specific
grammed to allow for moisture determination by heating the
temperatureandheldatthattemperatureforaprescribedlength
test specimens for a specified time period (for example, 1 h) at
of time. In thermogravimetric analysis, the mass of a sample in
the prescribed temperature limits.
a controlled atmosphere is recorded repeatedly as a function of
11.2 When using a muffle furnace for LOI determinations,
temperature or time.
always start the test with the muffle furnace at ambient
7.2 Drying Oven—For determining the moisture in solid
temperature.
combustion residue samples, use a drying oven with openings
12. Conditioning
for drying gas circulation and capable of temperature regula-
tion between the limits of 104 and 110°C. A drying gas flow
12.1 Heat new crucibles for use in these test methods under
rate of approximately one volume change per minute is
the conditions of the test and cool before use.
recommended but higher flow rates, that is, two volume
13. Procedure
changes per minute as in some other standard test methods for
coal and coke, are acceptable. 13.1 For LOI of moisture and ash, in analyses of solid
7.3 Crucibles, use a crucible of a convenient form that
combustion residues using a macro TGA, the analyses are
allows extensive contact between the specimen and reactant normally complete when the sample reaches a constant weight
gas. The crucibles can be made of porcelain, fused silica, or
as defined in the instrumental operating parameters.
similar materials. The crucibles shall have the dimensions 13.2 For LOI determinations using a single-step procedure,
specified by the instrument manufacturer.
add approximately1gof solid combustion residue to each
7.4 Balance, sensitive to 0.1 mg. In the macro TGA, the successive crucible and weigh. Select oxygen or air as the
balance is an integral part of the system. For other systems, the furnace atmosphere and raise the temperature of the furnace at
balance is a separate piece of a
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