Hostname: page-component-6898cfcb55-w5hgh Total loading time: 0 Render date: 2026-11-11T03:15:10.715Z Has data issue: false hasContentIssue false

A new kaolinite order index based on XRD profile fitting

Published online by Cambridge University Press:  09 July 2018

P. Aparicio*
Affiliation:
Departamento de Cristalografía, Mineralogía y Química Agrícola, Facultad de Química, Universidad de Sevilla, Apdo. 553, 41071 Sevilla, Spain
E. Galán
Affiliation:
Departamento de Cristalografía, Mineralogía y Química Agrícola, Facultad de Química, Universidad de Sevilla, Apdo. 553, 41071 Sevilla, Spain
R. E. Ferrell
Affiliation:
Department of Geology and Geophysics, Louisana State University Baton Rouge, LA 70803, USA
*
*E-mail: paparicio@us.es

Abstract

The determination of kaolinite order-disorder by X-ray diffraction is problematic due to overlapping peaks from associated kaolin minerals and X-ray amorphous phases. This paper presents a new index (Aparicio-Gala´n-Ferrell index — AGFI), measured on 02l and 11l reflections after decomposing individual peaks in the complex diffraction band in an effort to reduce interferences. The new index was tested with three kaolins, of varying structural order, and their admixtures containing different percentages of quartz, feldspar, illite, smectite, chlorite, halloysite and Fe hydroxides and silica gels. The AGFI is highly correlated with the percentage of low-defect kaolinite and the Hinckley Index. It is not as prone to interference by associated minerals and X-ray amorphous phases as other indices. The AGFI can be used to determine kaolinite order-disorder in a wide variety of kaolins and kaolinitic rocks; the only prerequisite is that the kaolinite content should be >10 wt.% in order for the results to be reproducible.

Information

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable