ASTM C867-94(2022)

Standard Test Method for Soluble Sulfate in Ceramic Whiteware Clays (Photometric Method)

ABSTRACT
This test method covers the procedures for determining soluble sulfate ions present in water or a filtrate using a photometer to measure the turbidity of precipitated barium sulfate. This test method also details a method for standardizing the photometer to be used. The soluble sulfate ions may be removed from clays or clay-water slurries by leaching with water during mixing and then filter pressing. An impractical number of washings would be needed to remove all sulfate ions, therefore, this test method should be considered only as a control test and not a quantitative analysis for sulfate ions. Test apparatus include a balance, high speed mixer, filter press, glass beakers, transfer pipets, spectrophotometer, measuring spoon, and other laboratory equipment. All reagents to be used should be of the required purity and concentration.
SCOPE
1.1 This test method covers the determination of soluble sulfate ions present in water or a filtrate by means of a photometer measuring the turbidity of precipitated barium sulfate. A method of standardizing the photometer for this test method is also given.  
1.2 Soluble sulfate ions may be removed from clays or clay-water slurries by leaching with water during mixing and subsequent filter pressing. To remove all the sulfate ions would require an impractical number of washings; therefore, this test method should be considered a control test and not a quantitative analysis for SO4 ions.  
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-Apr-2022
• ICS: 81.060.10 - Raw materials
• Technical Committee: C21 - Ceramic Whitewares and Related Products
• Drafting Committee: C21.04 - Raw Materials

Relations

• Refers: ASTM C324-01(2007) - Standard Test Method for Free Moisture in Ceramic Whiteware Clays
• Effective Date: 01-May-2007
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM C324-01e1 - Standard Test Method for Free Moisture in Ceramic Whiteware Clays
• Effective Date: 10-Oct-2001
• Refers: ASTM D1193-99e1 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999
• Refers: ASTM D1193-99 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999
• Refers: ASTM C324-82(1999) - Standard Test Method for Free Moisture in Ceramic Whiteware Clays
• Effective Date: 25-Jun-1982

Overview

ASTM C867-94(2022) is an international standard developed by ASTM International for the determination of soluble sulfate ions in ceramic whiteware clays using a photometric method. This test method utilizes photometric analysis to measure the turbidity caused by the precipitation of barium sulfate, thereby analyzing the presence of soluble sulfates in water or filtrate obtained from clay materials. The procedure includes standardized leaching, filtering, and measurement steps, making it a reliable control test for monitoring sulfate levels rather than a full quantitative analysis.

Key Topics

• Purpose: Establishes consistent procedures for detecting soluble sulfate ions in ceramic clay materials.
• Test Principle: Utilizes a photometer to assess turbidity from barium sulfate formation, correlating turbidity levels to sulfate concentration.
• Sample Preparation: Involves drying, grinding, mixing with water, and filter pressing clay to extract a representative filtrate for testing.
• Photometer Calibration: Details a method for standardizing the photometer with known sulfate solutions to ensure test accuracy and repeatability.
• Laboratory Equipment:
  • Analytical balance and high-speed mixer
  • Filter press operating up to 100 psi
  • Glass beakers, Erlenmeyer flasks, transfer pipettes
  • Spectrophotometer and necessary reagents (barium chloride, salt-acid reagent, glycerine reagent)
• Interpretation: Results offer a control test limiting the amount of washings needed, recognizing that complete sulfate removal by leaching is impractical.

Applications

The ASTM C867-94(2022) test method is primarily used in ceramic industries and laboratories concerned with raw material quality control:

• Quality Assurance: Helps ceramic manufacturers monitor and control the soluble sulfate content in whiteware clays, which is vital for consistent product quality and minimizing defects during production.
• Process Control: Supports routine checks during clay processing and slurry preparation, ensuring that soluble sulfate levels remain within acceptable operational limits.
• Research and Development: Aids materials scientists in developing new clay formulations and understanding the impact of soluble salts on ceramic properties.
• Regulatory Compliance: Assists manufacturers in adhering to industry and customer requirements regarding raw material purity and chemical content.

While the method is not intended for quantitative analysis of all sulfate ions present, it provides a standardized approach for comparative and routine testing.

Related Standards

Users of ASTM C867-94(2022) may also reference the following standards for complementary testing and procedures:

• ASTM C324: Test Method for Free Moisture in Ceramic Whiteware Clays
• ASTM D1193: Specification for Reagent Water
• American Chemical Society Reagent Chemicals: Specifications for laboratory reagents used during testing

Following these related standards further ensures the reliability of laboratory procedures and results when analyzing ceramic materials.

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Keywords: ASTM C867, soluble sulfate, ceramic whiteware clays, photometric method, sulfate test, barium sulfate turbidity, clay quality control, ceramic standards, raw material testing.

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: C867 − 94 (Reapproved 2022)
Standard Test Method for
Soluble Sulfate in Ceramic Whiteware Clays (Photometric
Method)
This standard is issued under the fixed designation C867; 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 2.2 American Chemical Society Document:
Specification for Reagent Chemicals
1.1 This test method covers the determination of soluble
sulfate ions present in water or a filtrate by means of a
3. Apparatus
photometer measuring the turbidity of precipitated barium
3.1 Balance, accurate to 0.0001 g.
sulfate. A method of standardizing the photometer for this test
method is also given. 3.2 High-Speed Mixer.
1.2 Soluble sulfate ions may be removed from clays or 3.3 Filter Press, capable of operating at 690 kPa (100 psi).
clay-water slurries by leaching with water during mixing and
3.4 Glass Beakers, Erlenmeyer Flasks.
subsequent filter pressing.To remove all the sulfate ions would
3.5 Transfer Pipets.
require an impractical number of washings; therefore, this test
method should be considered a control test and not a quanti- 3.6 Spectrophotometer and accessories.
tative analysis for SO ions.
3.7 Measuring Spoon, to hold approximately 0.2 g of BaCl
or THQ Cup.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.8 Other usual laboratory equipment, including timers, etc.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Reagents
mine the applicability of regulatory limitations prior to use.
4.1 Purity of Reagents—Reagent grade chemicals shall be
1.4 This international standard was developed in accor-
used in all tests. Unless otherwise indicated, it is intended that
dance with internationally recognized principles on standard-
all reagents shall conform to the specifications of the Commit-
ization established in the Decision on Principles for the
tee onAnalytical Reagents of theAmerican Chemical Society,
Development of International Standards, Guides and Recom-
where such specifications are available. Other grades may be
mendations issued by the World Trade Organization Technical
used, provided it is first ascertained that the regent is of
Barriers to Trade (TBT) Committee.
sufficiently high purity to permit its use without lessening the
accuracy of the determination.
2. Referenced Documents
4.2 Purity of Water—Unless otherwise indicated, references
2.1 ASTM Standards:
to water shall be understood to mean Type IV Grade reagent
C324 Test Method for Free Moisture in Ceramic Whiteware
water as defined in Specification D1193.
Clays
4.3 Barium Chloride (BaCl ·H O) crystals, 20 to 30 mesh.
2 2
D1193 Specification for Reagent Water
4.4 Salt-Acid Reagent—However, it can be prepared from:
23.6 mL HCl, 253.0 gm NaCl, 976.4 mL distilled water. This
solution should be stored in an automatic pipettor for accurate
measurement.
ThistestmethodisunderthejurisdictionofASTMCommitteeC21onCeramic
Whitewares and Related Products and is the direct responsibility of Subcommittee
C21.04 on Raw Materials. Available from American Chemical Society, 1155 16th Street, NW,
Current edition approved May 1, 2022. Published May 2022. Originally Washington, DC 20036.
approved in 1977. Last previous edition approved in 2014 as C867 – 94 (2014). ACS Reagent Chemicals, Specifications and Procedures for Reagents and
DOI: 10.1520/C0867-94R22. Standard-Grade Reference Materials, American Chemical Society, Washington,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
Standards volume information, refer to the standard’s Document Summary page on U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
the ASTM website. copeial Convention, Inc. (USPC), Rockville, MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C867 − 94 (2022)
4.5 Glycerine Reagent—a mixture of equal volumes of c. p. 6.2 A150-gportionofthegrounddriedclayisthenweighed
glycerine and reagent grade water or it may be purchased from to the nearest 0.1 g.
a laboratory supply house. This solution should be stored in an
6.3 Blunge the clay in 350 mLof reagent grade water for 30
automatic pipettor for accurate measurement.
min at high speed using the Hamilton Beach drink mixer.
4.6 Standard Sulfate Solution—a solution of c. p. sodium
6.4 Place a fresh piece of Baroid filter paper in the cylinder
sulfateinreagentgradewaterataconcentrationwhichcontains
of a Baroid Filter Press. Pour the slurry into the cylinder and
exactly 100 ppm of sulfate ion.
tighten the screw on the lid of the cylinder.
6.5 Pressure is applied gradually until 100 psi is obtained.
5. Standardization of Apparatus
Filtrate is caught in an Erlenmeyer flask. To eliminate errors
5.1 It should be noted that the instrument requires about 30
from initial turbidity, the first 5 mL of filtrate is discarded
...