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.

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 and health practices and determine the applicability of regulatory limitations prior to use.