ASTM D6558-22

Standard Test Method for Determination of TGA CO<inf>2</inf> Reactivity of Baked Carbon Anodes and Cathode Blocks

SIGNIFICANCE AND USE
5.1 The CO2 reactivity rates are used to quantify the tendency of a carbon artifact to react with carbon dioxide. Carbon consumed by these unwanted side reactions is unavailable for the primary reactions of reducing alumina to the primary metal. CO2  dusting rates are used to quantify the tendency of the coke aggregate or binder coke of a carbon artifact to selectively react with these gases. Preferential attack of the binder coke or coke aggregate of a carbon artifact by these gases causes some carbon to fall off or dust, making the carbon unavailable for the primary reaction of reducing alumina and, more importantly, reducing the efficiency of the aluminum reduction cell.  
5.2 Comparison of CO2 reactivity and dusting rates is useful in selecting raw materials for the manufacture of commercial anodes for specific smelting technologies in the aluminum reduction industry.  
5.3 CO2 reactivity rates are used for evaluating effectiveness and beneficiation processes or for research purposes.
SCOPE
1.1 This test method covers the thermogravimetric (TGA) determination of CO2  reactivity and dusting of shaped carbon anodes and cathode blocks used in the aluminum reduction industry. The apparatus selection covers a significant variety of types with various thermal conditions, sample size capability, materials of construction, and procedures for determining the mass loss and subsequent rate of reaction. This test method standardizes the variables of sample shape, reaction temperature, gas velocity over the exposed surfaces, and reaction time such that results obtained on different apparatuses are correlatable.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, 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: Published
• Publication Date: 30-Apr-2022
• ICS: 77.020 - Production of metals
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.05 - Properties of Fuels, Petroleum Coke and Carbon Material

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: D6558 − 22
Standard Test Method for
Determination of TGA CO Reactivity of Baked Carbon
2
1
Anodes and Cathode Blocks
This standard is issued under the fixed designation D6558; 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* Carbon Cathode Blocks Used in Aluminum Production
E691 Practice for Conducting an Interlaboratory Study to
1.1 This test method covers the thermogravimetric (TGA)
Determine the Precision of a Test Method
determination of CO reactivity and dusting of shaped carbon
2
anodes and cathode blocks used in the aluminum reduction
3. Terminology
industry.The apparatus selection covers a significant variety of
3.1 Definitions of Terms Specific to This Standard:
types with various thermal conditions, sample size capability,
3.1.1 dusting, n—that quantity of carbon that falls off the
materials of construction, and procedures for determining the
carbonartifactwhileinthereactionchamberandiscollectedin
mass loss and subsequent rate of reaction. This test method
the container at the bottom of the reaction chamber plus the
standardizes the variables of sample shape, reaction
quantity of carbon that is collected from the carbon artifact
temperature, gas velocity over the exposed surfaces, and
after cooling.
reactiontimesuchthatresultsobtainedondifferentapparatuses
are correlatable. 3.1.2 final CO reactivity, n—the mass loss of the carbon
2
artifact during the final 30 min of exposure to CO in the
2
1.2 The values stated in SI units are to be regarded as
reaction chamber divided by the initial geometric (right cylin-
standard. No other units of measurement are included in this
drical) exposed surface area of the sample, expressed as
standard.
milligrams per centimetre squared per hour.
1.3 This standard does not purport to address all of the
3.1.3 initial CO reactivity, n—the mass loss of the carbon
2
safety concerns, if any, associated with its use. It is the
artifact during the first 30 min of exposure to CO in the
2
responsibility of the user of this standard to establish appro-
reaction chamber divided by the initial geometric (right cylin-
priate safety, health, and environmental practices and deter-
drical) exposed surface area of the sample, expressed as
mine the applicability of regulatory limitations prior to use.
milligrams per centimetre squared per hour.
1.4 This international standard was developed in accor-
3.1.4 total CO reactivity, n—the total mass loss of the
dance with internationally recognized principles on standard-
2
carbon artifact (including dusting) during the total time that the
ization established in the Decision on Principles for the
sample is exposed to CO (60 min to 420 min) in the reaction
Development of International Standards, Guides and Recom-
2
chamber divided by the initial geometric (right cylindrical)
mendations issued by the World Trade Organization Technical
exposed surface area of the sample, expressed as milligrams
Barriers to Trade (TBT) Committee.
per centimetre squared per hour.
2. Referenced Documents
4. Summary of Test Method
2
2.1 ASTM Standards:
4.1 Initial, final, and total CO reactivity and dusting are
2
D6353 Guide for Sampling Plan and Core Sampling for
determined by passing carbon dioxide gas at flow rates giving
Prebaked Anodes Used in Aluminum Production
a standard velocity of reactant gas around cylindrically shaped
D6354 Guide for Sampling Plan and Core Sampling of
carbon artifacts under isothermal conditions for a specified
length of time. The reactivity is determined by continuously
1
This test method is under the jurisdiction of ASTM Committee D02 on monitoring the sample mass loss. The dusting term can be
Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of
determined by collecting and determining the mass of carbon
SubcommitteeD02.05onPropertiesofFuels,PetroleumCokeandCarbonMaterial.
particles that fall off the sample during reaction or collected
CurrenteditionapprovedMay1,2022.PublishedJuly2022.Originallyapproved
ɛ1
from the sample after the heat treatment.
in 2000. Last previous edition approved in 2015 as D6558 – 00a (2015) . DOI:
10.1520/D6558-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 5. Significance and Use
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.1 The CO reactivity rates are used to quantify the
Standards volume information, refer to the standard’s Document Summ
...

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: D6558 − 00a (Reapproved 2015) D6558 − 22
Standard Test Method for
Determination of TGA CO Reactivity of Baked Carbon
2
1
Anodes and Cathode Blocks
This standard is issued under the fixed designation D6558; 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
ε NOTE—SI unit formatting was corrected editorially in December 2015.
1. Scope Scope*
1.1 This test method covers the thermogravimetric (TGA) determination of CO reactivity and dusting of shaped carbon anodes
2
and cathode blocks used in the aluminum reduction industry. The apparatus selection covers a significant variety of types with
various thermal conditions, sample size capability, materials of construction, and procedures for determining the mass loss and
subsequent rate of reaction. This test method standardizes the variables of sample dimensions,shape, reaction temperature, gas
velocity over the exposed surfaces, and reaction time such that results obtained on different apparatuses are correlatable.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 safety, health, and healthenvironmental 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
2.1 ASTM Standards:
D6353 Guide for Sampling Plan and Core Sampling for Prebaked Anodes Used in Aluminum Production
D6354 Guide for Sampling Plan and Core Sampling of Carbon Cathode Blocks Used in Aluminum Production
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 dusting, n—that quantity of carbon that falls off the carbon artifact while in the reaction chamber and is collected in the
container at the bottom of the reaction chamber.chamber plus the quantity of carbon that is collected from the carbon artifact after
cooling.
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of Subcommittee
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved Oct. 1, 2015May 1, 2022. Published December 2015July 2022. Originally approved in 2000. Last previous edition approved in 20102015 as
ɛ1
D6558 – 00a (2010).(2015) . DOI: 10.1520/D6558-00AR15E01.10.1520/D6558-22.
2
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.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D6558 − 22
3.1.2 final CO reactivity,n—the mass loss of the carbon artifact during the final 30 min of exposure to CO in the reaction chamber
2 2
divided by the initial geometric (right cylindrical) exposed surface area of the sample, expressed as milligrams per centimetre
squared per hour.
3.1.3 initial CO reactivity,n—the mass loss of the carbon artifact during the first 30 min of exposure to CO in the reaction
2 2
chamber divided by the initial geometric (right cylindrical) exposed surface area of the sample, expressed as milligrams per
centimetre squared per hour.
3.1.4 total CO reactivity,n—the total mass loss of the carbon artifact (including dusting) during the total time that the sample is
2
exposed to CO (420 min) (60 min to 420 min) in the reaction chamber divided by the initial geometric (right cylindrical) exposed
2
surface area of the sample, expressed as milligrams per centimetre squared pe
...