ASTM C831-98(2017)e1

Standard Test Methods for Residual Carbon, Apparent Residual Carbon, and Apparent Carbon Yield in Coked Carbon-Containing Brick and Shapes 

SIGNIFICANCE AND USE
3.1 These test methods are designed for use with carbon-containing products. The residual carbon content of a coked carbon-containing brick or shape is an indication of how much carbon may be available, in service, to resist slag attack on, or oxidation loss of, that body. Apparent carbon yield gives an estimate of the relative efficiency of the total carbonaceous matter to be retained as residual carbon.  
3.2 Residual carbon has a direct bearing on several properties of a pitch or resin containing refractory such as ignited porosity, density, strength, and thermal conductivity.  
3.3 These test methods are suitable for product development, manufacturing control, and specification acceptance.  
3.4 These test methods are very sensitive to specimen size, coking rates, etc.; therefore, strict compliance with these test methods is critical.  
3.5 Appreciable amounts of reducible components, such as Fe2O3, will have a noticeable effect on the results. Thus, values obtained by these test methods will be different when brick removed from service is tested. This must be kept in mind when attempting to use these test methods in an absolute sense.  
3.6 Oxidizable components such as metals and carbides can have a noticeable effect on the results. This must be kept in mind when using the second procedure, which is based on measuring weight loss after igniting the coked specimens.  
3.7 Testing of brick or shapes that contain magnesium metal presents special problems since this metal is highly volatile and substantial amounts of the magnesium can be lost from the sample during the coking procedure. This must be kept in mind when interpreting the results of testing of brick that contains magnesium. In addition, magnesium can react readily with atmospheric humidity. This must be kept in mind when storing brick that contains magnesium.
SCOPE
1.1 These test methods cover the determination of residual carbon content in carbon-bearing brick and shapes after a prescribed coking treatment. They provide two procedures. The first procedure is based on the combustion of carbon and its measurement as carbon dioxide. However, when using the first procedure for articles that contain silicon carbide or other carbides, no distinction will be made between carbon present in the form of a carbide and carbon present as elemental carbon. The second procedure provides a method for calculating apparent residual carbon (on the basis of weight loss after igniting the coked specimens), apparent carbonaceous material content, and apparent carbon yield. If the second procedure is used for brick or shapes that contain metallic additives or carbides, it must be recognized that there will be a weight gain associated with the oxidation of the metals, or carbides, or both. Such a weight gain can change the results substantially and this must be kept in mind when interpreting the data.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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: Historical
• Publication Date: 31-Oct-2017
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: C08 - Refractories
• Drafting Committee: C08.04 - Chemical Behaviors

Relations

• Replaces: ASTM C831-98(2017) - Standard Test Methods for Residual Carbon, Apparent Residual Carbon, and Apparent Carbon Yield in Coked Carbon-Containing Brick and Shapes 
• Effective Date: 01-Nov-2017
• Replaced By: ASTM C831-18 - Standard Test Methods for Residual Carbon, Apparent Residual Carbon, and Apparent Carbon Yield in Coked Carbon-Containing Brick and Shapes
• Effective Date: 01-Feb-2018
• Referred By: ASTM C1190-18(2022) - Standard Practice for Location of Test Specimens from Magnesia-Carbon and Impregnated Burned Basic Brick
• Effective Date: 01-Nov-2017
• Referred By: ASTM C607-88(2016) - Standard Practice for Coking Large Shapes of Carbon-Bearing Materials
• Effective Date: 01-Nov-2017

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: C831 − 98 (Reapproved 2017)
Standard Test Methods for
Residual Carbon, Apparent Residual Carbon, and Apparent
Carbon Yield in Coked Carbon-Containing Brick and
Shapes
This standard is issued under the fixed designation C831; 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.
ε NOTE—Footnote 4 was removed editorially in November 2017.
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of residual 2.1 ASTM Standards:
carbon content in carbon-bearing brick and shapes after a D2906 Practice for Statements on Precision and Bias for
prescribed coking treatment. They provide two procedures. Textiles (Withdrawn 2008)
The first procedure is based on the combustion of carbon and E11 Specification for Woven Wire Test Sieve Cloth and Test
its measurement as carbon dioxide. However, when using the Sieves
first procedure for articles that contain silicon carbide or other
3. Significance and Use
carbides,nodistinctionwillbemadebetweencarbonpresentin
the form of a carbide and carbon present as elemental carbon.
3.1 These test methods are designed for use with carbon-
The second procedure provides a method for calculating
containing products. The residual carbon content of a coked
apparent residual carbon (on the basis of weight loss after
carbon-containing brick or shape is an indication of how much
igniting the coked specimens), apparent carbonaceous material
carbon may be available, in service, to resist slag attack on, or
content, and apparent carbon yield. If the second procedure is
oxidation loss of, that body. Apparent carbon yield gives an
used for brick or shapes that contain metallic additives or
estimate of the relative efficiency of the total carbonaceous
carbides, it must be recognized that there will be a weight gain
matter to be retained as residual carbon.
associated with the oxidation of the metals, or carbides, or
3.2 Residual carbon has a direct bearing on several proper-
both. Such a weight gain can change the results substantially
ties of a pitch or resin containing refractory such as ignited
and this must be kept in mind when interpreting the data.
porosity, density, strength, and thermal conductivity.
1.2 The values stated in inch-pound units are to be regarded
3.3 These test methods are suitable for product
as the standard. The values given in parentheses are for
development, manufacturing control, and specification accep-
information only.
tance.
1.3 This standard does not purport to address all of the
3.4 These test methods are very sensitive to specimen size,
safety concerns, if any, associated with its use. It is the
coking rates, etc.; therefore, strict compliance with these test
responsibility of the user of this standard to establish appro-
methods is critical.
priate safety, health, and environmental practices and deter-
3.5 Appreciable amounts of reducible components, such as
mine the applicability of regulatory limitations prior to use.
Fe O , will have a noticeable effect on the results.Thus, values
1.4 This international standard was developed in accor-
2 3
obtained by these test methods will be different when brick
dance with internationally recognized principles on standard-
removed from service is tested. This must be kept in mind
ization established in the Decision on Principles for the
when attempting to use these test methods in an absolute sense.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.6 Oxidizable components such as metals and carbides can
Barriers to Trade (TBT) Committee.
have a noticeable effect on the results. This must be kept in
1 2
These test methods are under the jurisdiction of ASTM Committee C08 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Refractories and are the direct responsibility of Subcommittee C08.04 on Chemical contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Behaviors. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2017. Published November 2017. Originally the ASTM website.
approved in 1976. Last previous edition approved in 2017 as C831 – 98 (2017). The last approved version of this historical standard is referenced on
DOI: 10.1520/C0831-98R17E01. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
C831 − 98 (2017)
mind when using the second procedure, which is based on 4.1.2 Inner and Outer Box, stainless steel (or equivalent
measuring weight loss after igniting the coked specimens. alloy), as shown in Figs. 1-3.
3.7 Testing of brick or shapes that contain magnesium metal
4.2 For CO Absorption:
presentsspecialproblemssincethismetalishighlyvolatileand
4.2.1 Laboratory Pulverizer, designed to provide a sealed,
substantial amounts of the magnesium can be lost from the
dust-proof grinding chamber, and having a capacity of at least
sample during the coking procedure.This must be kept in mind
50 g of sample.
when interpreting the results of testing of brick that contains
4.2.2 Combustion-Tube Furnace, capable of operating at
magnesium. In addition, magnesium can react readily with
183 °F (1000 °C)
atmospheric humidity. This must be kept in mind when storing
4.2.3 CO Absorption Train, as described in Fig. 4.
brick that contains magnesium.
NOTE 2—Commercial automatic and semi-automatic carbon determi-
4. Apparatus
nators may replace the apparatus described in 4.2.2 and 4.2.3.
4.1 For Coking:
4.3 The precision obtained with these instruments shall
4.1.1 Gas or Electric Furnace, with heating chamber ca-
meet the requirements specified in Section 10.
pable of receiving the coking box shown in Fig. 1.
NOTE 1—Samples should not be subjected to thermal gradients greater 5. Preparation of Test Specimens
than 40 °F (22 °C) during heatup. In electric furnaces with silicon carbide
5.1 This method assumes that the number of specimens
heating elements, the length of the box should be parallel to these
elements. tested will be a statistically valid sample of the entire lot of
FIG. 1 Outer Coking Box (Dimensions are in Inches)
´1
C831 − 98 (2017)
FIG. 2 Inner Coking Box
brick or shapes being evaluated. The exact number is usually nominal size of each slice shall be 1 by 3 by 6 in. (25 by 76 by
arrived at by mutual agreement between parties concerned.
152 mm). The two 1 by 3-in. faces and the two 1 by 6-in. faces
1 must be original surfaces.
5.2 Although sample brick from either the 4 ⁄2-in. (114-mm)
or the 6-in. (152-mm) series may be tested, it is preferable to
5.3 Test specimens may be cut wet or dry except for
use the larger size for the test. Cut slices 1 6 ⁄32 in. (25 6
products capable of hydration, such as dolomite brick, which
0.8 mm) in thickness perpendicular to the length at the mid-
must be cut dry and stored in a dry container prior to coking.
section of each sample brick or shape.As shown in Fig. 5, the
´1
C831 − 98 (2017)
FIG. 3 Coking Box Arrangement
FIG. 4 CO Absorption Train
5.4 Specimens that are cut wet must be dried immediately pores of the brick. Drying can usually be done on a forced-air
with a paper or cloth towel and flash dried. For pitch- dryer at 220 °F (105 °C) by limiting exposure to 5 to 10 min.
impregnated samples, flash drying should be done at a suffi- Repeat if necessary. These drying procedures are especially
ciently low temperature to avoid “weeping” of pitch from the important for metal-containing brick because hydration of the
´1
C831 − 98 (2017)
FIG. 5 Location of Test Specimen
metals can occur. Specimens containing a coating of pitch on 6.6 Heatthefurnacesothatthethermocouplewithinthebox
uncut surfaces, as is typical of an impregnation process, must registers 250 °F (120 °C) after the first hour, then heat the
be scraped clean prior to drying. furnace so that the box is heated at a rate of 400 6 20 °F (220
6 11 °C)⁄h to 1800 6 20 °F (980 6 11 °C).
5.5 Weigh all specimens after drying to constant weight
(60.2 g), recording weight to the nearest 0.1 g. This weight is
6.7 Holdthetemperaturefor3 6 ⁄2h,startingfromthetime
“as-received weight, A.” (This step may be omitted if residual
1780 °F (970 °C) is reached in the inner box.
carbon is to be determined by CO absorption, as indicated in
6.8 After completing the hold period, shut off the furnace
1.1.)
and allow the coking box to cool naturally within the furnace.
6. Procedure for Coking
6.9 Remove the samples from the coking box after the box
6.1 Place the test specimens randomly into the inner box, has cooled sufficiently to handle. After removing specimens
Fig. 2
from the inner box, clean by brushing carefully with a nylon or
naturalbristlebrushtoremoveclingingparticles.Thenproceed
NOTE 3—Burned pitch-impregnated magnesite brick should not be
to either of the two alternatives for analyzing the specimens.
coked with tempered, tar-bonded, or dolomite brick because of carbon
pickup by the impregnated samples and disruption of the bottom of
NOTE 6—After each run, clean the muffle and the bottom carbon plate
tempered samples. Pitch-bonded, pitch-bonded tempered magnesite brick,
of any adhering coke breeze.
and dolomite brick may be coked in the same box or coking run.
NOTE 4—The number of samples coked per run should be constant
6.10 Samples that contain dolomite or aluminum metal
within a laboratory. Dummy uncoked samples consistent with Note 3 may
should be stored in a sealed container containing dessicant in
be used to fill any empty positions in the inner box.
the time interval between coking and measurement of carbon
6.2 Place the inner box into the center of the outer box (Fig.
content. This is to prevent hydration of dolomite or aluminum
3), on the bottom of which has first been placed a ⁄2-in.
carbide. The aluminum carbide is formed by reaction between
(13-mm) slab of carbon, covered with a thin layer of dust-free
aluminum and carbon in the shape during the coking operation.
metallurgical-grade coke breeze (No. 14 (1.40-mm) sieve size)
Aluminum carbide can react with a water source such as
(Note 5). To ensure that the
...

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.
´1
Designation: C831 − 98 (Reapproved 2017) C831 − 98 (Reapproved 2017)
Standard Test Methods for
Residual Carbon, Apparent Residual Carbon, and Apparent
Carbon Yield in Coked Carbon-Containing Brick and
Shapes
This standard is issued under the fixed designation C831; 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.
ε NOTE—Footnote 4 was removed editorially in November 2017.
1. Scope
1.1 These test methods cover the determination of residual carbon content in carbon-bearing brick and shapes after a prescribed
coking treatment. They provide two procedures. The first procedure is based on the combustion of carbon and its measurement as
carbon dioxide. However, when using the first procedure for articles that contain silicon carbide or other carbides, no distinction
will be made between carbon present in the form of a carbide and carbon present as elemental carbon. The second procedure
provides a method for calculating apparent residual carbon (on the basis of weight loss after igniting the coked specimens),
apparent carbonaceous material content, and apparent carbon yield. If the second procedure is used for brick or shapes that contain
metallic additives or carbides, it must be recognized that there will be a weight gain associated with the oxidation of the metals,
or carbides, or both. Such a weight gain can change the results substantially and this must be kept in mind when interpreting the
data.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information
only.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 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:
C571 Test Method for Chemical Analysis of Carbon and Carbon-Ceramic Refractories (Withdrawn 1995)
D2906 Practice for Statements on Precision and Bias for Textiles (Withdrawn 2008)
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
3. Significance and Use
3.1 These test methods are designed for use with carbon-containing products. The residual carbon content of a coked
carbon-containing brick or shape is an indication of how much carbon may be available, in service, to resist slag attack on, or
oxidation loss of, that body. Apparent carbon yield gives an estimate of the relative efficiency of the total carbonaceous matter to
be retained as residual carbon.
3.2 Residual carbon has a direct bearing on several properties of a pitch or resin containing refractory such as ignited porosity,
density, strength, and thermal conductivity.
3.3 These test methods are suitable for product development, manufacturing control, and specification acceptance.
These test methods are under the jurisdiction of ASTM Committee C08 on Refractories and are the direct responsibility of Subcommittee C08.04 on Chemical Behaviors.
Current edition approved Nov. 1, 2017. Published November 2017. Originally approved in 1976. Last previous edition approved in 20132017 as C831 – 98 (2013).(2017).
DOI: 10.1520/C0831-98R17.10.1520/C0831-98R17E01.
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.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
C831 − 98 (2017)
3.4 These test methods are very sensitive to specimen size, coking rates, etc.; therefore, strict compliance with these test
methods is critical.
3.5 Appreciable amounts of reducible components, such as Fe O , will have a noticeable effect on the results. Thus, values
2 3
obtained by these test methods will be different when brick removed from service is tested. This must be kept in mind when
attempting to use these test methods in an absolute sense.
3.6 Oxidizable components such as metals and carbides can have a noticeable effect on the results. This must be kept in mind
when using the second procedure, which is based on measuring weight loss after igniting the coked specimens.
3.7 Testing of brick or shapes that contain magnesium metal presents special problems since this metal is highly volatile and
substantial amounts of the magnesium can be lost from the sample during the coking procedure. This must be kept in mind when
interpreting the results of testing of brick that contains magnesium. In addition, magnesium can react readily with atmospheric
humidity. This must be kept in mind when storing brick that contains magnesium.
4. Apparatus
4.1 For Coking:
4.1.1 Gas or Electric Furnace, with heating chamber capable of receiving the coking box shown in Fig. 1.
NOTE 1—Samples should not be subjected to thermal gradients greater than 40 °F (22 °C) during heatup. In electric furnaces with silicon carbide
heating elements, the length of the box should be parallel to these elements.
4.1.2 Inner and Outer Box, stainless steel (or equivalent alloy), as shown in Figs. 1-3.
FIG. 1 Outer Coking Box (Dimensions are in Inches)
´1
C831 − 98 (2017)
FIG. 2 Inner Coking Box
4.2 For CO Absorption:
4.2.1 Laboratory Pulverizer, designed to provide a sealed, dustproofdust-proof grinding chamber, and having a capacity of at
least 50 g of sample.
4.2.2 Combustion-Tube Furnace, capable of operating at 183 °F (1000 °C)
4.2.3 CO Absorption Train, as described in Fig. 4 and in Test Method C571.
NOTE 2—Commercial automatic and semi-automatic carbon determinators may replace the apparatus described in 4.2.2 and 4.2.3.
4.3 The precision obtained with these instruments shall meet the requirements specified in Section 10.
´1
C831 − 98 (2017)
FIG. 3 Coking Box Arrangement
FIG. 4 CO Absorption Train
5. Preparation of Test Specimens
5.1 This method assumes that the number of specimens tested will be a statistically valid sample of the entire lot of brick or
shapes being evaluated. The exact number is usually arrived at by mutual agreement between parties concerned.
5.2 Although sample brick from either the 4 ⁄2-in. (114-mm) or the 6-in. (152-mm) series may be tested, it is preferable to use
the larger size for the test. Cut slices 1 6 ⁄32 in. (25 6 0.8 mm) in thickness perpendicular to the length at the mid-section of each
´1
C831 − 98 (2017)
sample brick or shape. As shown in Fig. 5, the nominal size of each slice shall be 1 by 3 by 6 in. (25 by 76 by 152 mm). The two
1 by 3-in. faces and the two 1 by 6-in. faces must be original surfaces.
5.3 Test specimens may be cut wet or dry except for products capable of hydration, such as dolomite brick, which must be cut
dry and stored in a dry container prior to coking.
5.4 Specimens that are cut wet must be dried immediately with a paper or cloth towel and flash dried. For pitch-impregnated
samples, flash drying should be done at a sufficiently low temperature to avoid “weeping” of pitch from the pores of the brick.
Drying can usually be done on a forced-air dryer at 220 °F (105 °C) by limiting exposure to 5 to 10 min. Repeat if necessary. These
drying procedures are especially important for metal-containing brick because hydration of the metals can occur. Specimens
containing a coating of pitch on uncut surfaces, as is typical of an impregnation process, must be scraped clean prior to drying.
5.5 Weigh all specimens after drying to constant weight (60.2 g), recording weight to the nearest 0.1 g. This weight is
“as-received weight, A.” (This step may be omitted if residual carbon is to be determined by CO absorption, as indicated in 1.1.)
6. Procedure for Coking
6.1 Place the test specimens randomly into the inner box, Fig. 2
NOTE 3—Burned pitch-impregnated magnesite brick should not be coked with tempered, tar-bonded, or dolomite brick because of carbon pickup by
the impregnated samples and disruption of the bottom of tempered samples. Pitch-bonded, pitch-bonded tempered magnesite brick, and dolomite brick
may be coked in the same box or coking run.
NOTE 4—The number of samples coked per run should be constant within a laboratory. Dummy uncoked samples consistent with Note 3 may be used
to fill any empty positions in the inner box.
6.2 Place the inner box into the center of the outer box (Fig. 3), on the bottom of which has first been placed a ⁄2-in. (13-mm)
slab of carbon, covered with a thin layer of dust-free metallurgical-grade coke breeze (No. 14 (1.40-mm) sieve size) (Note 5). To
ensure that the coke breeze is free of moisture which could oxidize carbon during cooking, dry the coke at 400 °F (205 °C) for
24 h, and keep in a closed container at room temperature until needed.
NOTE 5—Detailed requirements for sieves are given in Specification E11.
6.3 Place the thermocouple well into the center of the inner box and put the lid on the inner box. The thermocouple well must
be long enough to extend above the cover of the outer box.
6.4 Cover the inner box with metallurgical-grade coke breeze retained on a No. 14 sieve and place a loose-fitting lid over the
coke breeze (see Fig. 3). Pack the coke breeze between the edges of the lid and box.
6.5 Place the coking box assembly (Fig. 3) into the furnace, and insert a calibrated thermocouple into the thermocouple well.
6.6 Heat the furnace so that the thermocouple within the box registers 250 °F (120 °C) after the first hour, then heat the furnace
so that the box is heated at a rate of 400 6 20 °F (220 6 11 °C) ⁄h to 1800 6 20 °F (980 6 11 °C).
6.7 Hold the temperature for 3 6 ⁄2 h, starting from the time 1780 °F (970 °C) is reached in the inner box.
6.8 After completing the hold period, shut off the furnace and allow the coking box to cool naturally within the furnace
...