ASTM E2295-21

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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
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Designation: E2295 − 13 E2295 − 21
Standard Practice for
Fire Assay Silver Corrections in Analysis of Metal Bearing
Ores, Concentrates, and Related Metallurgical Materials by
Silver Determination in Slags and Cupels
This standard is issued under the fixed designation E2295; 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 determination of silver corrections for fire assay of metal bearing ores, concentrates, and related
metallurgical materials using the spent slags and cupels from the fire assay process, by gravimetry and atomic absorption
spectrophotometry.
1.2 The test methods appear in the following order:
Sections
Gravimetric Method 10–11
Atomic Absorption Method 12–13
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.4 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 Guide 35:1989.)
1.5 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:
D1193 Specification for Reagent Water
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
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 Nov. 1, 2013Nov. 15, 2021. Published December 2013December 2021. Originally approved in 2003. Last previous edition approved in 20082013
ε1
as E2295 – 03E2295 – 13. (Reapproved 2008) . DOI: 10.1520/E2295-13.10.1520/E2295-21.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2295 − 21
E1024 Guide for Chemical Analysis of Metals and Metal Bearing Ores by Flame Atomic Absorption Spectrophotometry
(Withdrawn 2004)
E1335 Test Methods for Determination of Gold in Bullion by Fire Assay Cupellation Analysis
2.2 ISO Documents:
ISO Guide 35:1989 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.
4. Summary of Practice
4.1 In the process of fire assay fusion slags and cupels are collected, retreated and silver is determined in them to provide a
correction value for the fire assay determination of silver (see Guide E1024, Test Methods E1335, ISO 10378:1994,
5 6
ISO 10378:2016, Bugbee, and Smith ).
5. Significance and Use
5.1 These methods are primarily intended to be used for the determination of silver correction in the fire assay silver
determination. Silver assays are determined by fire assay for the purpose of metallurgical exchange between seller and buyer.
5.2 It is assumed that all who use this method 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 Analytical Balance, capable of weighing to 0.01 g.
6.2 Analytical Balance, capable of weighing to 0.001 mg.
6.3 Assay Furnace, capable of temperatures up to 1100 °C, accurate to 6 5 °C.
6.4 Atomic Absorption Spectrophotometry, AAS.
6.5 Ring Grinder, 250 g capacity.
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 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Type I or II of Specification D1193. Type III or IV may be used if they effect no measurable change in the blank or sample.
The last approved version of this historical standard is referenced on www.astm.org.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.ISO
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
Bugbee, E. E., A Textbook of Fire Assaying, Third Ed., John Wiley and Sons, Inc., Hoboken, NJ, 1946.
Smith, E. A., The Sampling and Assay of the Precious Metals, Second Ed., Charles Griffin and Co., Ltd., 1947.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
E2295 − 21
7.3 Borax, sodium tetraborate (Na B O ), technical grade.
2 4 7
7.4 Ammonium Chloride Solution (NH Cl 250g/L)—Add 250 g of ammonium chloride to 500 mL of water in a 1-L1 L volumetric
flask. Dilute to the mark and mix.
7.5 Crucibles, standard fire assay.
7.6 Cupels, magnesite (MgCO ) or bone ash.
7.7 Flour, common baking grade.
7.8 Litharge (PbO),technical grade, silver free.
7.9 Silica Sand (SiO ),technical grade.
7.10 Sodium Carbonate (Na CO ),technical grade.
2 3
8. Hazards
8.1 For precautions to be observed in this practice, refer to Practice E50.
8.2 All precautions and safe laboratory operating procedures should be followed when using HClO .
9. Sampling and Sample Preparation
9.1 Weigh the Determine the mass of the fire assay slags and cupels (7.6) from the duplicate fusion and cupellation processes for
each test sample on a balance to 0.
...