ASTM D3906-97

1.1 This test method covers determining relative zeolite diffraction intensities.

1.2 The term "zeolite" here is restricted to those zeolites having the faujasite crystal structure, including X and Y zeolites, the various cation exchange forms, and the dealuminized, decationated, and ultrastable forms. These zeolites have cubic symmetry with unit cell parameter within the limits 24.2 and 25.0 A (2.42 and 2.50 nm). The samples contemplated include zeolite preparations in the various forms and catalysts containing these zeolites.

1.3 The term "intensity of an X-ray powder diffraction (XRD) peak" is the "integral intensity," either the area of counts under the peak or the product of the peak height and the peak width.

1.4 The method provides a number that is the ratio of intensity of portions of the XRD pattern of the sample to intensity of the corresponding portion of the pattern of a reference zeolite, NaY. (Laboratories may use other zeolite, for example, REY as a secondary standard.) The intensity ratio, expressed as a percentage, is then labeled "% XRD intensity/NaY."

1.5 Under certain conditions such a ratio is the percent zeolite in the sample. These conditions include:

1.5.1 The zeolite in the sample is the same as the reference zeolite.

1.5.2 The absorption for the X-rays used is the same for the zeolite and the nonzeolite portions of the sample.

1.6 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.