ASTM E1568-21

Standard Test Method for Determination of Gold in Activated Carbon by Fire Assay Gravimetry

SIGNIFICANCE AND USE
5.1 In the primary metallurgical processes used by the mineral processing industry for gold bearing ores, gold is extracted with alkaline cyanide solutions and adsorbed onto activated carbon for recovery of the metal. Metallurgical accounting, process control, and ore evaluation procedures for this type of mineral processing plant depend on accurate, precise, and prompt measurements of gold concentrations in the activated carbon.  
5.2 This test method for gold in activated carbon is intended primarily as a referee method to test such materials for metal content. It is assumed that those who use these procedures will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures will be followed. Appropriate quality control practices must be followed, such as those described in Guide E882.
SCOPE
1.1 This test method covers the determination of gold in activated carbon by fire assay collection and gravimetric measurement. It covers the range of 15 μg/g to 5000 μg/g gold.  
1.2 Units—The values stated in SI units are to be regarded as the 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. For specific hazards statements, see Section 9, 11.2.3 – 11.2.5, and 11.3.4.  
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: 14-Nov-2021
• ICS: 77.120.99 - Other non-ferrous metals and their alloys
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.02 - Ores, Concentrates, and Related Metallurgical Materials

Relations

• Refers: ASTM E135-20 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jan-2020
• Refers: ASTM E1601-19 - Standard Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
• Effective Date: 01-Nov-2019
• Refers: ASTM E135-19 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2019
• Refers: ASTM D2866-11(2018) - Standard Test Method for Total Ash Content of Activated Carbon
• Effective Date: 01-Jun-2018
• Refers: ASTM E50-17 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Sep-2017
• Refers: ASTM E882-10(2016)e1 - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E882-10(2016) - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E50-11(2016) - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Aug-2016
• Refers: ASTM E135-16 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2016
• Refers: ASTM E135-15a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jul-2015
• Refers: ASTM E135-15 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2015
• Refers: ASTM E135-14b - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Aug-2014
• Refers: ASTM E135-14a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Apr-2014
• Refers: ASTM E135-14 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Feb-2014
• Refers: ASTM E135-13a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Dec-2013

Overview

ASTM E1568-21 provides a standardized test method for the determination of gold content in activated carbon using fire assay collection and gravimetric measurement techniques. Developed by ASTM International, this standard is crucial for ensuring accurate and precise measurement of gold concentrations, particularly within the mineral processing industry. The method is designed for a gold concentration range of 15 μg/g to 5000 μg/g and supports key operational needs such as metallurgical accounting, process control, and ore evaluation.

Key Topics

• Test Scope and Range

  • Measures gold concentrations in activated carbon between 15 μg/g and 5000 μg/g.
  • Utilizes fire assay fusion followed by gravimetric analysis for quantification.

• Significance and Practical Use

  • Essential for accurate metallurgical accounting in gold extraction operations.
  • Used as a referee method for verifying gold content in activated carbon samples.

• Required Laboratory Practices

  • Appropriate for users proficient in laboratory techniques and proper safety procedures.
  • Emphasizes quality control and compliance with established laboratory standards.

• Sample Preparation and Analysis

  • Includes specific sample drying, pulverizing, and sieving steps.
  • Involves ignition, fusion, cupellation, parting, and weighing of gold beads.

• Hazards and Safety

  • Highlights risks due to toxic materials such as lead and recommends safety practices as per ASTM E50.
  • Stresses the importance of working in a controlled, well-ventilated laboratory environment.

Applications

The ASTM E1568-21 standard is primarily applicable to:

• Gold Extraction and Recovery Plants

  • Used to determine the gold loading on activated carbon in cyanide leaching plants.
  • Provides precise data for process monitoring, optimization, and gold yield assessment.

• Metallurgical Laboratories

  • Serves as a referee method for evaluating gold in activated carbon during lab analyses.
  • Supports interlaboratory comparison, quality assurance, and control processes.

• Mineral Processing Industry

  • Vital for accurate ore evaluation, especially for plants utilizing cyanide-based gold extraction methods.
  • Assists in compliance with regulatory and internal reporting requirements for gold content validation.

• Research and Development

  • Utilized in studies investigating gold adsorption efficiency or optimizing activated carbon use.

Related Standards

Several ASTM standards are referenced within ASTM E1568-21 to support sample preparation, analysis, and quality control:

• ASTM D2862 - Test Method for Particle Size Distribution of Granular Activated Carbon
• ASTM D2866 - Test Method for Total Ash Content of Activated Carbon
• ASTM D2867 - Test Methods for Moisture in Activated Carbon
• ASTM E29 - Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• ASTM E50 - Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• ASTM E882 - Guide for Accountability and Quality Control in the Chemical Analysis Laboratory

Summary

ASTM E1568-21 delivers a reliable, gravimetric method for determining gold in activated carbon, supporting the accuracy required for process control and regulatory compliance in gold recovery operations. By adhering to this standard, organizations can optimize their procedures, enhance gold recovery rates, and ensure the highest levels of data quality and laboratory safety.

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: E1568 − 21
Standard Test Method for
Determination of Gold in Activated Carbon by Fire Assay
Gravimetry
This standard is issued under the fixed designation E1568; 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 erations for Chemical Analysis of Metals, Ores, and
Related Materials
1.1 This test method covers the determination of gold in
E135 Terminology Relating to Analytical Chemistry for
activated carbon by fire assay collection and gravimetric
Metals, Ores, and Related Materials
measurement.Itcoverstherangeof15 µg⁄gto5000 µg⁄ggold.
E173 Practice for Conducting Interlaboratory Studies of
1.2 Units—The values stated in SI units are to be regarded
Methods for Chemical Analysis of Metals (Withdrawn
as the standard. No other units of measurement are included in 3
1998)
this standard.
E276 Test Method for Particle Size or Screen Analysis at
1.3 This standard does not purport to address all of the
4.75 mm (No. 4) Sieve and Finer for Metal-Bearing Ores
safety concerns, if any, associated with its use. It is the and Related Materials
responsibility of the user of this standard to establish appro-
E300 Practice for Sampling Industrial Chemicals
priate safety, health, and environmental practices and deter- E882 Guide for Accountability and Quality Control in the
mine the applicability of regulatory limitations prior to use.
Chemical Analysis Laboratory
For specific hazards statements, see Section 9, 11.2.3 – 11.2.5, E1601 Practice for Conducting an Interlaboratory Study to
and 11.3.4.
Evaluate the Performance of an Analytical Method
1.4 This international standard was developed in accor-
3. Terminology
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.1 Definitions—For definitions of terms used in this test
Development of International Standards, Guides and Recom-
method, refer to Terminology E135.
mendations issued by the World Trade Organization Technical
4. Summary of Test Method
Barriers to Trade (TBT) Committee.
4.1 The weighed test sample is ignited and fused with fire
2. Referenced Documents
assay flux in a clay crucible. The lead metal from the fusion is
2.1 ASTM Standards: separated and the precious metals concentrated by oxidation
D2862 Test Method for Particle Size Distribution of Granu- and adsorption of the lead on a cupel.The gold is annealed and
lar Activated Carbon the silver is parted with nitric acid. The mass is determined on
D2866 Test Method for Total Ash Content of Activated a semi-microbalance.
Carbon
5. Significance and Use
D2867 Test Methods for Moisture in Activated Carbon
E29 Practice for Using Significant Digits in Test Data to
5.1 In the primary metallurgical processes used by the
Determine Conformance with Specifications
mineral processing industry for gold bearing ores, gold is
E50 Practices for Apparatus, Reagents, and Safety Consid-
extracted with alkaline cyanide solutions and adsorbed onto
activated carbon for recovery of the metal. Metallurgical
accounting, process control, and ore evaluation procedures for
This test method is under the jurisdiction of ASTM Committee E01 on
this type of mineral processing plant depend on accurate,
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
precise, and prompt measurements of gold concentrations in
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
the activated carbon.
lurgical Materials.
Current edition approved Nov. 15, 2021. Published December 2021. Originally
5.2 This test method for gold in activated carbon is intended
approved in 1993. Last previous edition approved in 2013 as E1568 – 13. DOI:
primarily as a referee method to test such materials for metal
10.1520/E1568-21.
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 last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1568 − 21
content. It is assumed that those who use these procedures will 8.6 Litharge (PbO)—Lead oxide powder, with gold content
be trained analysts capable of performing common laboratory less than 0.001 µg/g.
proceduresskillfullyandsafely.Itisexpectedthatworkwillbe
8.7 Silicon Dioxide (SiO )—Silicon dioxide powder, with
performed in a properly equipped laboratory and that proper
gold content less than 0.001 µg/g.
waste disposal procedures will be followed. Appropriate qual-
8.8 Silver Foil—99.9 % minimum, with gold content less
ity control practices must be followed, such as those described
than 0.001 µg/g.
in Guide E882.
8.9 Sodium Carbonate (Na CO )—Sodium carbonate
2 3
6. Interferences
powder, with gold content less than 0.001 µg/g.
6.1 Elements normally found in ore processing activated
8.10 Strong HNO (1 + 2) Parting Solution—Add 330 mL
carbon do not interfere. When present, platinum group metals
HNO to 660 mL of water.
may be reported as gold in gravimetric fire assay determina-
8.11 Weak HNO (1 + 4) Parting Solution—Add 200 mL
tions and must be less than 0.1 mg in the final gold bead.
HNO to 800 mL water.
7. Apparatus
9. Hazards
7.1 Analytical Balance, capable of weighing to 0.1 g.
9.1 Refer to Practices E50 for precautions to be observed in
7.2 Assay Mold, 100 mL capacity.
this test method.
7.3 Cupel, magnesite, 30 g lead capacity.
9.2 Use care when handling hot crucibles and operating
7.4 Drying Oven, having forced air circulation, with tem-
furnaces in order to avoid personal injury by either burn or
perature control between 145 °C and 155 °C.
electrical shock.
7.5 Fire Clay Crucible, 30 g sample capacity.
9.3 Lead and litharge are toxic materials and are volatile at
relatively low temperatures. Use accepted safety procedures to
7.6 Hot Plate, having variable temperature control, used
avoid inhalation, ingestion, or skin contact.
with ventilation control for acid fumes.
9.4 Refer to Warnings in 11.2.3 – 11.2.5, and 11.3.4.
7.7 Jeweler’s Rolls, capable of flattening doré beads.
7.8 Muffle Furnace, having air circulation with draft
10. Sampling
controls, capable of temperatures to 1100 °C, accurate to 6
10.1 Collect the sample in accordance with Practice E300.
10 °C, used with ventilation controls for lead fumes.
Samplesmustbefreeofanyextraneousmaterialssuchassand,
7.9 Roasting Dish, 15 g sample capacity.
rocks, and wood.
7.10 Semi-Microbalance, capable of weighing to 0.01 mg.
10.2 Sample Preparation—Dry the sample, in accordance
with the Oven-Drying Method of Test Methods D2867,to
8. Reagents
constant weight at 150 °C. If the analysis of a particular
8.1 Purity of Reagents—Reagent grade chemicals shall be
particle size range is desired, separate fractions in accordance
used in all tests. Unless otherwise indicated, it is intended that
with Test Method D2862.
all reagents shall conform to the specifications of the Commit-
10.3 Test Sample—Pulverize the gross sample so that at
tee onAnalytical Reagents of theAmerican Chemical Society,
least90 %passesa150 µm(No.100or100mesh,Tyler)sieve,
where such specifications are available. Other grades may be
in accordance with Test Method E276. Mix the gross sample.
used, provided it is first ascertained that the reagent is of
Determine the mass of duplicate test samples of
sufficiently high purity to permit its use without lessenin
...

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.
Designation: E1568 − 13 E1568 − 21
Standard Test Method for
Determination of Gold in Activated Carbon by Fire Assay
Gravimetry
This standard is issued under the fixed designation E1568; 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 test method covers the determination of gold in activated carbon by fire assay collection and gravimetric measurement.
It covers the range of 15 μg ⁄g to 5000 μg ⁄g gold.
1.2 Units—The values stated in SI units are to be regarded as the 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. For specific hazards statements, see Section 9 and , 11.2.3 – 11.2.5, 11.3.4, and
11.3.4.
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:
D2862 Test Method for Particle Size Distribution of Granular Activated Carbon
D2866 Test Method for Total Ash Content of Activated Carbon
D2867 Test Methods for Moisture in Activated Carbon
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
E173 Practice for Conducting Interlaboratory Studies of Methods for Chemical Analysis of Metals (Withdrawn 1998)
E276 Test Method for Particle Size or Screen Analysis at 4.75 mm (No. 4) Sieve and Finer for Metal-Bearing Ores and Related
Materials
E300 Practice for Sampling Industrial Chemicals
E882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
This test method 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 April 1, 2013Nov. 15, 2021. Published June 2013December 2021. Originally approved in 1993. Last previous edition approved in 20082013 as
ε1
E1568 – 03 (2008)E1568 – 13. . DOI: 10.1520/E1568-13.10.1520/E1568-21.
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
E1568 − 21
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminology E135.
4. Summary of Test Method
4.1 The weighed test sample is ignited and fused with fire assay flux in a clay crucible. The lead metal from the fusion is separated
and the precious metals concentrated by oxidation and adsorption of the lead on a cupel, cupel. The gold is annealed and the silver
is parted with nitric acid, and the gold is annealed and weighed on a microbalance.acid. The mass is determined on a
semi-microbalance.
5. Significance and Use
5.1 In the primary metallurgical processes used by the mineral processing industry for gold bearing ores, gold is extracted with
alkaline cyanide solutions and adsorbed onto activated carbon for recovery of the metal. Metallurgical accounting, process control,
and ore evaluation procedures for this type of mineral processing plant depend on accurate, precise, and prompt measurements of
gold concentrations in the activated carbon.
5.2 This test method for gold in activated carbon is intended primarily as a referee method to test such materials for metal content.
It is assumed that those who use these procedures will be trained analysts capable of performing common laboratory procedures
skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal
procedures will be followed. Appropriate quality control practices must be followed, such as those described in Guide E882.
6. Interferences
6.1 Elements normally found in ore processing activated carbon do not interfere. When present, platinum group metals may be
reported as gold in gravimetric fire assay determinations and must be less than 0.1 mg in the final gold bead.
7. Apparatus
7.1 Analytical Balance, capable of weighing to 0.1 g.
7.2 Assay Mold, 100-mL100 mL capacity.
7.3 Cupel, magnesite, 30-g30 g lead capacity.
7.4 Drying Oven, having forced air circulation, with temperature control between 145 °C and 155 °C.
7.5 Fire Clay Crucible, 30-g30 g sample capacity.
7.6 Hot Plate, having variable temperature control, used with ventilation control for acid fumes.
7.7 Jeweler’s Rolls, capable of flattening doré beads.
7.8 Muffle Furnace, having air circulation with draft controls, capable of temperatures to 1100 °C, accurate to 6 10 °C, used with
ventilation controls for lead fumes.
7.9 Roasting Dish, 15 g sample capacity.
7.10 Semi-Microbalance, capable of weighing to 0.01 mg.0.01 mg.
7.10 Roasting Dish, 15-g sample capacity.
E1568 − 21
8. Reagents
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall 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.
8.2 Ammonia Wash Solution, NH OH (1 + 17)(1 + 17)——Add 100 mL NH OH to 1700 mL of water.
4 4
8.3 Borax—Borax (Na B O )—NaSodium B O —Sodium borate powder, with gold content less than 0.001 μg/g.
2 4 7 2 4 7
8.4 Fire Assay Flux Mixture—Mix 575 g of litharge (PbO) with 275 g of soda ash (Na CO ), 75 g of borax (Na B O ), 75 g of
2 3 2 4 7
silica silicon dioxide (SiO ), and 30 g of baking flour.
8.5 Lead Foil—99.9 % minimum, with gold content less than 0.001 μg/g.
8.6 PbO—Litharge (PbO)—Lead oxide powder, with gold content less than 0.001 μg/g.
8.7 SiOSilicon Dioxide (SiO —)—Silicon dioxide powder, with gold content less than 0.001 μg/g.
8.8 Silver Foil—99.9 % minimum, with gold content less than 0.001 μg/g.
8.9 NaSodium Carbonate (Na CO —)—Sodium carbonate powder, with gold content less than 0.001 μg/g.
2 3
8.10 Strong HNO (1 + 2) Parting Solution—Add 330 mL HNO to 660 mL of water.
3 3
8.11 Weak HNO (1 + 4) Parting Solution—Add 200 mL HNO to 800 mL water.
3 3
9. Hazards
9.1 Refer to Practices E50 for precautions to be observed in this test method.
9.2 Use care when handling hot crucibles and operating furnaces in order to avoid personal injury by either burn or electrical
shock.
9.3 Lead and PbOlitharge are toxic materials and are volatile at relatively low temperatures. Use accepted safety procedures to
avoid inhalation, ingestion, or skin contact.
9.4 Refer to WARNINGSWarnings in 11.2.3 – 11.2.5, 11.3.4, and 11.3.4.
10. Sampling
10.1 Collect the sample in accordance with Practice E300. Samples must be free of any extraneous materials such as sand, rocks,
and wood.
10.2 Sample Preparation—Dry the sample, in accordance with the Oven-Drying Method of Test Methods D2867, to constant
weight at 150 °C. If the analysis of a particular particle size range is desired, separate fractions in accordance with Test Method
D2862.
Reage
...