ASTM C866-11(2022)

Standard Test Method for Filtration Rate of Ceramic Whiteware Clays

ABSTRACT
This standard test method covers the rate determination of clay-water paste layer formation from a clay-water slip under pressure filtration. Filter pressing of clay shall be in accordance to the procedure indicated in this specification. Calculation of filtration rate and void fraction shall depend on thickness of wet filter cake and filtration time. Void fraction in the filter cake shall depend on filter cake weight, filter press cross-sectional area, and wet filter cake thickness.
SCOPE
1.1 This test method covers the determination of the rate at which a layer of clay-water paste is formed from a clay-water slip under pressure filtration. The filtration rate is directly related to such whiteware operations as filter pressing, slip casting, and drying of ware in which water permeability through a clay-water paste is the controlling mechanism.  
1.2 A straight-line relationship exists between the time of filter pressing and the square of the thickness of the paste layer. The filtration rate is directly related to the filter press pressure and the void fraction of the paste layer, and is inversely related to the square of the clay surface area, the ratio of solids to liquid in the slip, and the viscosity of water at the testing temperature.  
1.3 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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.

General Information

• Status: Published
• Publication Date: 31-Jan-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 C324-01e1 - Standard Test Method for Free Moisture in Ceramic Whiteware Clays
• Effective Date: 10-Oct-2001
• Refers: ASTM C324-82(1999) - Standard Test Method for Free Moisture in Ceramic Whiteware Clays
• Effective Date: 25-Jun-1982

Overview

ASTM C866-11(2022): Standard Test Method for Filtration Rate of Ceramic Whiteware Clays provides a systematic procedure for measuring the rate at which a clay-water paste layer forms from a clay-water slip under pressure filtration. This test method is essential for evaluating the filtration behavior of ceramic whiteware clays, a property directly influencing key manufacturing operations such as filter pressing, slip casting, and drying. By determining the filtration rate and void fraction, manufacturers and laboratories can better understand the water permeability of their clay bodies and optimize processing parameters for improved ceramic product quality.

Key Topics

• Filtration Rate Determination
  The method measures the thickness of the wet filter cake and the time taken to form it, offering insights into the permeability of various ceramic whiteware clays.
• Pressure Filtration Process
  The test uses defined pressure conditions to simulate real-world filter pressing operations, ensuring relevant and reproducible results.
• Void Fraction Calculation
  The void fraction of the filter cake is calculated using the cake's weight, filter press area, and wet cake thickness, providing valuable information on the packing structure of the clay particles.
• Data Relationships
  The test identifies the direct relationship between filtration rate and factors such as press pressure and void fraction, and an inverse relationship with clay surface area, solid-to-liquid ratio, and water viscosity.
• Relevant Equipment
  Simple laboratory apparatus such as a precise balance, blender, filter press, stop watch, and vernier calipers are used for repeatable measurements.

Applications

• Ceramic Whiteware Manufacturing
  The standard is widely used by ceramic manufacturers to monitor and control the filter pressing and slip casting steps, directly impacting product consistency and processing efficiency.
• Quality Control
  Laboratories employ this test method to assess raw clay materials for suitability in whiteware production, ensuring optimal filtration characteristics for their intended applications.
• Clay Body Formulation
  Material scientists use the filtration rate and void fraction results as critical parameters when developing or modifying clay formulations for specific production processes.
• Process Optimization
  Determining how quickly and efficiently water can be removed from clay bodies enables process engineers to optimize filter press cycle times and improve energy efficiency during drying.

Related Standards

• ASTM C324 - Test Method for Free Moisture in Ceramic Whiteware Clays:
  Provides a complementary procedure for determining the moisture content of clays, important for accurate and consistent filtration testing.
• Other ASTM C21 Committee Standards:
  ASTM C866 is part of a broader suite of standards aimed at raw materials and products for ceramic whiteware, which address additional properties such as particle size distribution, plasticity, and chemical composition.

Keywords: ASTM C866, filtration rate, ceramic whiteware clays, void fraction, filter press, slip casting, ceramic manufacturing, permeability, ASTM standards, quality control.

By following ASTM C866-11(2022), laboratories and manufacturers can ensure reliable measurement of filtration behavior in ceramic whiteware clays, supporting higher-quality products and more efficient production processes. For more details and the latest updates, refer to the ASTM website.

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: C866 − 11 (Reapproved 2022)
Standard Test Method for
Filtration Rate of Ceramic Whiteware Clays
This standard is issued under the fixed designation C866; 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 3. Apparatus
1.1 This test method covers the determination of the rate at 3.1 Balance, 0.001-g sensitivity.
which a layer of clay-water paste is formed from a clay-water
3.2 Blender.
slip under pressure filtration. The filtration rate is directly
3.3 Filter Press, capable of operation at 345 kPa (50 psi).
related to such whiteware operations as filter pressing, slip
casting, and drying of ware in which water permeability
3.4 Stop Watch.
through a clay-water paste is the controlling mechanism.
3.5 Vernier Calipers, capable of measuring thickness to the
1.2 A straight-line relationship exists between the time of
nearest 0.1 mm.
filter pressing and the square of the thickness of the paste layer.
4. Procedure
The filtration rate is directly related to the filter press pressure
and the void fraction of the paste layer, and is inversely related
4.1 Weigh 100 g of clay, dried in accordance with Test
to the square of the clay surface area, the ratio of solids to
Method C324, to the nearest 0.1 g and mix with 300 mL of
liquid in the slip, and the viscosity of water at the testing
water measured to the nearest 1.0 mL for 10 min in a blender.
temperature.
4.2 Store the slip in a closed container for at least 24 h to
1.3 The values stated in acceptable metric units are to be
allow the clay and water to reach equilibrium conditions.
regarded as the standard. The values given in parentheses are
4.3 Remix the clay-water slurry for 5 min in the blender.
for information only.
4.4 Pour the clay-water slurry into the filter press and apply
1.4 This standard does not purport to address all of the
345 kPa (50 psi) air pressure for 30 min.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.5 Relieve the pressure from the filter press and then pour
priate safety, health, and environmental practices and deter- the clay-water slurry from the top of the filter cake that has
mine the applicability of regulatory limitations prior to use. formed. A sharp movement of the wrist is required to remove
1.5 This international standard was developed in accor-
all of the remaining slip from the filter press.
dance with internationally recognized principles on standard-
4.6 Record the temperature of the filtrate.
ization established in the Decision on Principles for the
4.7 Reapply air pressure to the filter press for 10 min to
Development of International Standards, Guides and Recom-
force some of the water from the cake that has formed.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
NOTE 1—Some clays have a fast filtration rate and the air may pass
through the cake in less than 10 min. In this case, the air pressure should
be relieved as soon as the sound of air emitting from the press is detected.
2. Referenced Documents
4.8 Remove the filter cake from the press and measure the
2.1 ASTM Standards:
thickness to the nearest 0.1 mm with the vernier calipers.
C324 Test Method for Free Moisture in Ceramic Whiteware
Clays
...