ASTM D3906-19

4.1 Zeolites Y and X, particularly for catalyst and adsorbent applications, are a major article of manufacture and commerce. Catalysts and adsorbents comprising these zeolites in various forms plus binder and other components have likewise become important. 4.2 This X-ray procedure is designed to monitor these 4.3 Drastic changes in intensity of individual peaks in the XRD patterns of Y and X can result from changes of distribution of electron density within the unit cell of the zeolite. The electron density distribution is dependent upon the extent of filling of pores in the zeolite with guest molecules, and on the nature of the guest molecules. In this XRD method, the guest molecule H_{4.3.1 Because of the factors mentioned in 4.3 that could vary the intensities of the XRD peaks, this XRD method will provide the best determination of relative crystallinity when the reference and sample have a similar history of preparation and composition.}

4.4 Corrections are possible that can make this XRD method accurate for measuring percent zeolite in many specific situations. These corrections are well known to those skilled in X-ray diffraction. It is not practical to specify those corrections here.

1.1 This test method covers the determination of relative X-ray diffraction intensities of zeolites having the faujasite crystal structure, including synthetic 1.2 The samples include zeolite preparations in the various forms, and catalysts and adsorbents 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 This test 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 a modified 1.5 Under certain conditions such a ratio is the percent zeolite in the sample. These conditions include:

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

1.7 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.