If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

The charge of component layers of illite-smectite in bentonites and the nature of end-member illite

$28.00 plus tax (Refund Policy)

Buy Article:

Abstract:

The nature of component layers of mixed-layer illite-smectite and their possible evolution in the course of illitization have been debated since the 1960s. The present study is a new attempt to solve these problems, using samples collected from diverse geological formations around the world. Twenty three purified illite-smectites from bentonites and hydrothermal rocks, covering the complete range of expandability, were analyzed chemically, including NH4+ determination, and their structural formulae were calculated. The exchangeable cations (EXCH) were plotted vs. the fixed cations (FIX) yielding the following experimental regression:

EXCH = − 0.43 × FIX + 0.41 (R2 = 0.98)

FIX and EXCH depend on the charge of the illite (Qi) and smectite (Qs) interlayers, and the fractions of these interlayers in the bulk clay leading to:

EXCH = −Qs/Qi × FIX + Qs

Analysis of these relations and independent measurements of the total specific surface area (TSSA) indicate that the layer charges of both types do not change in the course of illitization. The smectite layer charge is equal to 0.41 and the illite layer charge is equal to 0.95 per O10(OH)2. End-member illite has a well defined composition that is close to intermediate between muscovite and phengite, with fixed cations content greater than that specified in the AIPEA classification of layer silicates:

FIX0.95(Si3.25Al0.75)(Al1.81Fe0.01Mg0.19)O10(OH)2

The established relationship allows the calculation of the mean number (N) of 2:1 layers in all fundamental particles and also the fraction of smectitic layers (fs) from FIX:

N = Qi/(Qi – FIX) fs = (Qi – FIX)/Qi

N and fs can be used to calculate TSSA, and all three parameters can also be calculated from cation exchange capacity and from X-ray diffraction peak positions, utilizing the regressions established here.
More about this publication?
  • The JOURNAL publishes articles of interest to the international community of clay scientists, including but not limited to areas in mineralogy, crystallography, geology, geochemistry, sedimentology, soil science, agronomy, physical chemistry, colloid chemistry, ceramics, petroleum engineering, foundry engineering, and soil mechanics. Clays and Clay Minerals exists to disseminate to its worldwide readership the most recent developments in all of these aspects of clay materials. Manuscripts are welcome from all countries.

    Clays and Clay Minerals is the official publication of The Clay Minerals Society.

    The Editor-in-Chief is Professor Joseph W. Stucki jstucki@illinois.edu

    Publications of The Clay Minerals Society
    Source Clays

  • Editorial Board
  • Information for Authors
  • Membership Information
  • Annual Meeting of The Clay Minerals Society
  • ingentaconnect is not responsible for the content or availability of external websites
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
UA-1313315-24
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more