ASTM E738-20

Standard Test Method for Determination of Aluminum in Iron Ores and Related Materials by EDTA Complexometric Titrimetry

SIGNIFICANCE AND USE
5.1 This test method for the analysis of iron ore concentrates and agglomerates is primarily intended as a referee method to test for compliance with compositional specifications. It is assumed that all who use this test method 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 shall be followed, such as those described in Guide E882.
SCOPE
1.1 This test method2 covers the determination of aluminum in iron ores, concentrates, and agglomerates in the compositional range from 0.25 % to 5 % aluminum.
Note 1: As used in this test method (except as related to the term relative standard deviation), “percent” or “%” refers to mass fraction (mass/mass) of the form g/100 g.  
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-Jun-2020
• ICS: 73.060.10 - Iron ores
• 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 E135-19 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2019
• 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) - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• 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 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
• Refers: ASTM E50-11 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 15-Oct-2011
• Refers: ASTM E135-11b - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Sep-2011

Overview

ASTM E738-20 is the standard test method developed by ASTM International for the determination of aluminum content in iron ores, concentrates, and agglomerates using EDTA complexometric titrimetry. Covering the analytical range of 0.25% to 5% aluminum (by mass), this method is primarily used to verify compliance with material composition specifications. The procedure is intended for trained analysts using properly equipped laboratories and emphasizes adherence to comprehensive safety and quality control practices. As a referee method, ASTM E738-20 plays a crucial role in assuring the quality and integrity of iron ore materials throughout their supply chain.

Key Topics

• Scope and Purpose: Applicable to iron ores and related materials, this standard addresses compositional analysis for compliance purposes using an internationally recognized test procedure.
• Test Methodology: It involves fusing the sample, dissolving it, selective precipitation, and titrating aluminum with EDTA using a complexometric method and zinc standard solution.
• Analytical Range: Suitable for samples with 0.25% to 5% aluminum content by mass.
• Laboratory Requirements: Designed for skilled personnel in fully equipped analytical laboratories following strict safety, environmental, and quality guidelines.
• Data Quality and Accuracy:
  • Use of reagent grade chemicals and high-purity water per ASTM specifications.
  • Sample preparation standards ensure consistent, accurate results.
• Interferences: The method is robust-elements normally found in iron ores do not interfere with the determination of aluminum.
• Safety and Compliance: Laboratories must establish and follow proper health, safety, and waste disposal practices, in line with ASTM E50 and applicable regulations.

Applications

The ASTM E738-20 standard test method is widely used across various sectors where iron ore constitutes a critical raw material. Its main applications include:

• Iron & Steel Industry: Ensuring raw material quality in the production and processing of iron and steel by verifying that aluminum levels remain within allowable ranges.
• Mining and Metallurgy: Supporting exploration, beneficiation, and quality control activities by providing accurate compositional data for iron ore concentrates and agglomerates.
• Referee Analysis: Serving as an authority method for dispute resolution and verification of aluminum content in iron ore shipments between buyers, sellers, and regulatory authorities.
• Research and Development: Facilitating the development of new ore processing methods and material blends that rely on precise knowledge of elemental composition.
• Accredited Testing Laboratories: Meeting the requirements for ISO/IEC 17025-accredited laboratories and those participating in interlaboratory comparison programs.

Related Standards

ASTM E738-20 references and complements several other standards to ensure robust, harmonized testing protocols in the field of analytical chemistry for metals and ores:

• ASTM E135: Terminology relating to analytical chemistry for metals, ores, and related materials.
• ASTM E50: Practices for apparatus, reagents, and safety considerations for chemical analysis of metals, ores, and related materials.
• ASTM E877: Practice for sampling and sample preparation of iron ores and related materials for determination of chemical composition and physical properties.
• ASTM E882: Guide for accountability and quality control in the chemical analysis laboratory.
• ASTM D1193: Specification for reagent water, establishing water purity standards suitable for chemical analyses.
• ASTM E29: Practice for using significant digits in test data to determine conformance with specifications.

These related standards help ensure that testing is accurate, reliable, and in line with internationally recognized best practices, supporting global trade and regulatory compliance across the iron and steel value chain.

Keywords: ASTM E738-20, aluminum in iron ore, EDTA titrimetry, complexometric titration, iron ore analysis, metallurgical quality control, referee method, laboratory testing standard.

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: E738 − 20
Standard Test Method for
Determination of Aluminum in Iron Ores and Related
Materials by EDTA Complexometric Titrimetry
This standard is issued under the fixed designation E738; 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 E135 Terminology Relating to Analytical Chemistry for
2 Metals, Ores, and Related Materials
1.1 This test method covers the determination of aluminum
E877 Practice for Sampling and Sample Preparation of Iron
in iron ores, concentrates, and agglomerates in the composi-
Ores and Related Materials for Determination of Chemi-
tional range from 0.25 % to 5 % aluminum.
cal Composition and Physical Properties
NOTE 1—As used in this test method (except as related to the term
E882 Guide for Accountability and Quality Control in the
relative standard deviation), “percent” or “%” refers to mass fraction
(mass/mass) of the form g/100 g.
Chemical Analysis Laboratory
1.2 The values stated in SI units are to be regarded as
3. Terminology
standard. No other units of measurement are included in this
3.1 Definitions—For definitions of terms used in this test
standard.
method, refer to Terminology E135.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 The sample is fused in a zirconium crucible with a
priate safety, health, and environmental practices and deter-
mixed flux of sodium carbonate and sodium peroxide. The
mine the applicability of regulatory limitations prior to use.
fused mass is dissolved in dilute HCl. The R O (Note 2)
2 3
1.4 This international standard was developed in accor-
hydroxides are precipitated with NH OH and redissolved in
dance with internationally recognized principles on standard-
HCl. Iron, titanium, and so forth, are removed with cupferron
ization established in the Decision on Principles for the
and chloroform. The aqueous phase is treated with HNO and
Development of International Standards, Guides and Recom-
HClO and evaporated to dryness. After dissolving in dilute
mendations issued by the World Trade Organization Technical
HCl, the solution is filtered, and the filtrate is treated with an
Barriers to Trade (TBT) Committee.
excess of ethylenediaminetetraacetic acid (EDTA). The excess
EDTA is titrated with a standard zinc solution using xylenol
2. Referenced Documents
orange indicator. Ammonium fluoride is added to release the
2.1 ASTM Standards: EDTA bound to aluminum. This EDTA is then titrated with
D1193 Specification for Reagent Water standard zinc solution, and the percent aluminum is calculated.
NOTE 2—R O hydroxides are rare earth sesquioxides such as La O ,
E29 Practice for Using Significant Digits in Test Data to
2 3 2 3
Y O,Ce O,Gd O , and Eu O .
2 3 2 3 2 3 2 3
Determine Conformance with Specifications
E50 Practices for Apparatus, Reagents, and Safety Consid-
5. Significance and Use
erations for Chemical Analysis of Metals, Ores, and
5.1 Thistestmethodfortheanalysisofironoreconcentrates
Related Materials
and agglomerates is primarily intended as a referee method to
test for compliance with compositional specifications. It is
assumed that all who use this test method will be trained
This test method is under the jurisdiction of ASTM Committee E01 on
analysts capable of performing common laboratory procedures
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal- skillfully and safely. It is expected that work will be performed
lurgical Materials.
in a properly equipped laboratory and that proper waste
Current edition approved July 1, 2020. Published July 2021. Originally approved
disposal procedures will be followed. Appropriate quality
in1980.Lastpreviouseditionapprovedin2011asE738–11,whichwaswithdrawn
control practices shall be followed, such as those described in
January 2020 and reinstated in July 2020. DOI: 10.1520/E0738-20.
Bhargava, O. P., “Complexometric Determination of Aluminum in Iron Ore,
Guide E882.
Sinter, Concentrates, and Agglomerates,” Talanta, Vol 26, 1979, pp. 146 to 148.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6. Interferences
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.1 None of the elements normally found in iron ores
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. interfere with this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E738 − 20
7. Apparatus undissolved metal, add 2-mL increments of water followed by
simmering until complete solution is obtained. Add 50 mL of
7.1 Zirconium Crucible, 50-mL.
water and gently boil for 2 min. Cool. By dropwise addition of
NaOH solution B, adjust the pH to 4. Dilute to 1 L with water
8. Reagents and Materials
in a volumetric flask.
8.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
9. Hazards
all reagents conform to the specifications of the Committee on
9.1 For precautions to be observed in this method, refer to
Analytical Reagents of the American Chemical Society where
Practices E50.
such specifications are available. Other grades may be used,
provided it is first ascertained that the reagent is of sufficient
10. Sampling and Sample Preparation
high purity to permit its use without lessening the accuracy of
the determination.
10.1 Sample the material in accordance with Practice E877.
8.2 Purity of Water—Unless otherwise indicated, references
10.2 Pulverize the laboratory sample to pass a 150-µm (No.
towatershallbeunderstoodtomeanreagentwaterconforming
100).
to Type I or II of Specification D1193. Type III or IV may be
NOTE 3—To facilitate decomposition, some ores, such as specular
used if they effect no measurable change in the blank or
hematite, require grinding to pass a 75-µm (No. 200) sieve.
sample.
8.3 Ammonium Chloride Solution (10 g/L)—Dissolve 10 g
11. Procedure
ofammoniumchloride(NH Cl)inwateranddiluteto1L.Add
11.1 Select and weigh a test sample as follows:
2 drops (0.1 mL) of NH OH per 100 mL of solution.
Tolerance in Test Sample
8.4 Ammonium Fluoride Solution—Dissolve 10 g of ammo-
Aluminum, % Test Sample Mass, g mass, mg
nium fluoride (NH F) in 100 mL of water in a polyethylene
0.25 to 1 0.3 5
beaker. Prepare fresh each day.
1to2 0.2 5
2to5 0.1 5
8.5 Chloroform (CHCl ).
Transfer the prepared sample to a small weighing bottle
8.6 Cupferron Solution (60 g/L)—Dissolve6gof cupferron
previously dried at about 105 °C. Dry the bottle and contents
in 80 mL of cold water, dilute to 100 mL, and filter. Prepare
for1hat105°Cto110°C.Capthe bottle and cool to room
fresh as needed.
temperature in a desiccator. Momentarily release the cap to
8.7 Ethylenediaminetetraacetic Acid (EDTA) Solution (0.01
equalize the pressure and weigh the capped bottle and sample
mol/L).
to the nearest 0.1 mg. Repeat the drying and weigh
...