ASTM D3872-05(2019)

Standard Test Method for Ferrous Iron in Iron Oxides

SIGNIFICANCE AND USE
3.1 This test method may be used for production quality control or specification acceptance.
SCOPE
1.1 This test method covers the quantitative determination of ferrous oxide (FeO) by oxidation of ferrous iron (Fe++) in an acid solution to the ferric state (Fe+++) and titration with potassium dichromate using diphenylamine as the indicator.  
1.2 This test method is applicable to synthetic black iron oxide, natural black iron oxide, magnetite or brown iron oxide where part of the iron content is present in the ferrous state (Note 1). It is applicable to iron oxides where the ferrous iron content ranges from 50 to 0.20 %.  
Note 1: Natural iron oxides and magnetite may contain traces of metallic iron that will be combined with and analyzed as FeO.  
1.3 This standard does not purport to address the safety concerns if any, problems 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-2019
• ICS: 71.060.20 - Oxides
• ICS: 77.080.10 - Irons
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.31 - Pigment Specifications

Relations

• Replaces: ASTM D3872-05(2011) - Standard Test Method for Ferrous Iron in Iron Oxides
• Effective Date: 01-May-2019
• Refers: ASTM D280-01(2012) - Standard Test Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• Effective Date: 01-Nov-2012
• Refers: ASTM D280-01(2007) - Standard Test Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• Effective Date: 01-Feb-2007
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D280-81(1995) - Standard Test Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• Effective Date: 10-May-2001
• Refers: ASTM D280-01 - Standard Test Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• Effective Date: 10-May-2001
• Refers: ASTM D1193-99 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999
• Refers: ASTM D1193-99e1 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999
• Referred By: ASTM D769-01(2019) - Standard Specification for Black Synthetic Iron Oxide
• Effective Date: 01-May-2019
• Referred By: ASTM D3724-01(2019) - Standard Specification for Synthetic Brown Iron Oxide Pigment
• Effective Date: 01-May-2019

Overview

ASTM D3872-05(2019), Standard Test Method for Ferrous Iron in Iron Oxides, establishes a precise procedure for determining the quantity of ferrous oxide (FeO) through the oxidation of ferrous iron (Fe²⁺) to the ferric state (Fe³⁺) in an acid solution, followed by titration with potassium dichromate and diphenylamine as the indicator. This method is applicable to a range of iron oxides-such as synthetic black iron oxide, natural black iron oxide, magnetite, or brown iron oxide-where a portion of the iron content exists in the ferrous form.

This ASTM standard is essential for production quality control and specification acceptance in industries utilizing iron oxides, providing a reliable analytical approach for evaluating the ferrous iron content across a broad concentration range. The method covers ferrous iron concentrations from 50% down to 0.20%, making it suitable for both high and low FeO content materials.

Key Topics

• Quantitative Analysis of Ferrous Iron: Uses oxidation and titration to precisely measure FeO in iron oxide samples.
• Applicable Material Types: Effective for synthetic and natural iron oxides, including magnetite, where ferrous iron is present.
• Concentration Range: Suitable for samples with 0.20% to 50% ferrous iron content.
• Test Method Steps:
  • Digestion of sample in acid (with careful handling to prevent oxidation of Fe²⁺)
  • Titration using potassium dichromate and diphenylamine indicator
  • Calculation and reporting of FeO content
• Quality and Specification: Provides a standardized approach for routine quality assurance and acceptance criteria.
• Precision and Reproducibility: Outlines expected repeatability and reproducibility between laboratories for reliable results.
• Sample and Reagent Handling: Highlights the importance of careful sample preparation and reagent purity for accurate outcomes.

Applications

ASTM D3872-05(2019) is widely used in industries where iron oxide materials play a critical role, including:

• Pigments Manufacturing: Ensures iron oxide pigments meet quality standards for color and performance.
• Metallurgical Processes: Controls ferrous iron content in ore and sintering processes for steel and iron production.
• Ceramics and Building Materials: Verifies iron oxide additives comply with product specifications.
• Environmental and Geological Analysis: Assesses mineral composition and iron cycling in soils and rocks.
• Research & Development: Used in laboratory studies to characterize and compare iron oxide materials.

The method's reliability and broad concentration range make it a default choice for specification acceptance, supply chain verification, and routine process control.

Related Standards

When implementing or referencing ASTM D3872-05(2019), the following standards are also commonly associated:

• ASTM D280 - Test Methods for Hygroscopic Moisture (and Other Matter Volatile Under the Test Conditions) in Pigments
• ASTM D1193 - Specification for Reagent Water
• Reference Standards for Reagents - American Chemical Society Specifications
• National Institute of Standards and Technology (NIST) standard samples for method calibration

These related standards help ensure that test results are consistent, accurate, and comparable across different laboratories and industries.

By following ASTM D3872-05(2019), laboratories and manufacturers can maintain rigorous quality control, ensure regulatory compliance, and guarantee the specification acceptance of iron oxide materials in various applications. For more information, visit the ASTM International website and refer to the full standard documentation.

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: D3872 − 05 (Reapproved 2019)
Standard Test Method for
Ferrous Iron in Iron Oxides
This standard is issued under the fixed designation D3872; 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 4. Apparatus
1.1 This test method covers the quantitative determination
4.1 The digestion apparatus consists of a standard 500-mL
++
of ferrous oxide (FeO) by oxidation of ferrous iron (Fe )inan
Erlenmeyer flask fitted with a two-hole rubber stopper and
+++
acid solution to the ferric state (Fe ) and titration with
glass tubing, as shown in Fig. 1, to provide for the introduction
potassium dichromate using diphenylamine as the indicator.
of the inert gas and vent for gas and digestion fumes.
1.2 This test method is applicable to synthetic black iron
oxide, natural black iron oxide, magnetite or brown iron oxide 5. Reagents
where part of the iron content is present in the ferrous state
5.1 Purity of Reagents—Reagent grade chemicals shall be
(Note 1). It is applicable to iron oxides where the ferrous iron
used in all tests. Unless otherwise indicated, it is intended that
content ranges from 50 to 0.20 %.
all reagents shall conform to the specifications of the Commit-
NOTE 1—Natural iron oxides and magnetite may contain traces of
tee onAnalytical Reagents of theAmerican Chemical Society,
metallic iron that will be combined with and analyzed as FeO. 3
where such specifications are available. Other grades may be
1.3 This standard does not purport to address the safety
used, provided it is first ascertained that the reagent is of
concerns if any, problems associated with its use. It is the
sufficiently high purity to permit its use without lessening the
responsibility of the user of this standard to establish appro-
accuracy of the determination.
priate safety, health, and environmental practices and deter-
5.2 Purity of Water—Unless otherwise indicated, references
mine the applicability of regulatory limitations prior to use.
to water shall be understood to mean Type II of Specification
1.4 This international standard was developed in accor-
D1193.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5.3 Diphenylamine Indicator—Dissolve1gof diphenylam-
Development of International Standards, Guides and Recom-
ine in 100 mL of concentrated (H SO ) (sp gr 1.84).
2 4
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5.4 Hydrochloric Acid (1+1)—Dilute concentrated hydro-
chloric acid (HCl, sp gr 1.19) with an equal volume of reagent
2. Referenced Documents
water.
2.1 ASTM Standards:
5.5 Iron Ore, Standard, Sibley No. 27-f.
D280 Test Methods for Hygroscopic Moisture (and Other
5.6 Potassium Dichromate, Standard Solution (0.1 N)—
Matter Volatile Under the Test Conditions) in Pigments
D1193 Specification for Reagent Water Dissolve 4.904 g of K Cr O in water and dilute to 1 L.
2 2 7
Standardize against National Institute of Standards and Tech-
3. Significance and Use
nology standard sample No. 27f of Sibley iron ore. Calculate
the Fe factor in grams per millilitre for the solution as:
3.1 This test method may be used for production quality
control or specification acceptance.
Fe 5 W/V (1)
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of Reagent Chemicals, American Chemical Society Specifications, American
Subcommittee D01.31 on Pigment Specifications. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Current edition approved May 1, 2019. Published May 2019. Originally listed by the American Chemical Society, see Analar Standards for Laboratory
approved in 1979. Last previous edition approved in 2011 as D3872 – 05 (2011). Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
DOI: 10.1520/D3872-05R19. and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or MD.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM May be secured from National Institute of Standards and Technology, Depart-
Standards volume information, refer to the standard’s Document Summary page on ment of Commerce, Washington, DC 20234. Other recognized primary iron
the ASTM website. standard may be substituted.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3872 − 05 (2019)
FIG. 1 Digestion Apparatus
to avoid generating heat, as additional grinding could oxidize ferrous to
where:
ferric iron.
W = weight of Fe in the standard iron ore (not the solution,
as there is none), and
7. Procedure
V =K Cr O required f
...