ASTM E2296-21

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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: E2296 − 03 (Reapproved 2013) E2296 − 21
Standard Practice for
Silver Corrections in Metal Bearing Ores, Concentrates, and
Related Metallurgical Materials by Fire Assay Slag Recycling
and Cupel Proof Gravimetry
This standard is issued under the fixed designation E2296; 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 This practice covers the silver loss correction, utilizing slag recycling and cupellation of proof silver during the fire assay of
metal bearing ores, concentrates, and related metallurgical materials.
1.2 Units—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. (See Practices E50 and ISO 35:1989.)ISO 35:2006.)
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:
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E50 Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
2.2 ISO Documents:
ISO 35:1989ISO 35:2006 Certification of Reference Materials—General and Statistical Principles
ISO 10378:1994ISO 10378:2016 Copper Sulfide Concentrates—Determination of Gold and Silver Contents—Fire Assay
Gravimetric and Atomic Absorption Spectrometric Method
3. Terminology
3.1 Definitions—For definitions of terms used in this practice, refer to Terminology E135.
This practice is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
Subcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.
Current edition approved Oct. 1, 2013Nov. 15, 2021. Published October 2013December 2021. Originally approved in 2003. Last previous edition approved in 20082013
as E2296 – 03 (2008)ε1.(2013). DOI: 10.1520/E2296-03R13.10.1520/E2296-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.ISO Central
Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
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E2296 − 21
4. Summary of Practice
4.1 In the process of fire assay fusion, the slag is retained from the initial fusion and reprocessed through the fusion procedure.
The resulting lead button is combined with the preliminary lead button during cupellation. Proof silver is carried through the
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cupellation procedure to determine the silver losses. (See ISO 10378:1994, ISO 10378:2016, Bugbee, and Smith .)
5. Significance and Use
5.1 This practice is primarily intended to be used for the correction of silver loss in the fire assay process. Silver contents are
determined by fire assay for the purpose of metallurgical exchange between buyer and seller. It is assumed that all who use this
practice will be trained analysts capable of performing skillfully and safely. It is expected that work will be performed in a properly
equipped laboratory under appropriate quality control practices such as those described in Guide E882.
6. Apparatus
6.1 Assay Furnace, capable of temperatures up to 1100 °C, accurate to 6 5 °C with draft controls.
6.2 Analytical Balance, capable of weighing determining mass to 0.001 mg.
6.3 Hammer, blacksmith type.
6.4 Hammering Block, flat steel or iron.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
7.2 Borax, sodium tetraborate (Na B O ),technical grade.
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7.3 Crucibles, standard fire assay clay.
7.4 Cupels, magnesite (MgCO ) or bone ash, size determined by lead button weight.mass.
NOTE 1—Cupel size is determined by the weightmass of the lead button. Cupels must be large enough to hold all th
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