Thermally modified clay minerals

L. Heller-Kallai*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

65 Scopus citations

Abstract

Changes in temperature alter the structure and properties of clay minerals. Four temperature ranges are distinguished: (1) Temperatures sufficiently low to cause partial freezing of clay mineral dispersions or pastes: in this temperature range some of the water is converted into ice, but some remains in a liquid or semi-liquid state. (2) Temperatures above dehydration, but below dehydroxylation, when clay minerals lose adsorbed and hydration water: the interlayer spaces collapse, pore space is changed and surface acidity is substantially altered. (3) Temperatures above dehydroxylation, but below those leading to complete breakdown of the structure: the changes occurring in this temperature range vary for different clay mineral groups. Dehydroxylation destroys the layer structure of trioctahedral, but not that of dioctahedral 2:1 type minerals. Kaolinite group minerals become amorphous to X-rays, although some features of the structural framework are preserved. (4) Temperatures at which some minerals turn amorphous, others recrystallise to new phases.

Original languageEnglish
Title of host publicationHandbook of Clay Science Fundamentals
PublisherElsevier B.V.
Pages411-433
Number of pages23
ISBN (Print)9780080982588
DOIs
StatePublished - 2013

Publication series

NameDevelopments in Clay Science
Volume5
ISSN (Print)1572-4352

Keywords

  • acidity
  • de- and rehydration
  • dehydroxylation
  • Freezing
  • porosity
  • structural changes
  • texture

Fingerprint

Dive into the research topics of 'Thermally modified clay minerals'. Together they form a unique fingerprint.

Cite this