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High‐Temperature Reactions of Clay Mineral Mixtures and Their Ceramic Properties: IV, Dimensional and Weight Changes on Refiring and the Pore‐Size Distribution of Fired Kaolinite‐Muscovite‐Quartz Mixtures with 25 Wt% Quartz
Author(s) -
COLE W. F.,
CROOK D. N.
Publication year - 1968
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1968.tb11841.x
Subject(s) - muscovite , kaolinite , mica , moisture , mineralogy , water content , quartz , volume (thermodynamics) , materials science , chemistry , composite material , geology , geotechnical engineering , thermodynamics , physics
Dimensional and weight changes on refiring of clay mineral mixtures were used as a measure of moisture expansion and moisture uptake, respectively. Pore‐size distributions were measured by the mercury penetration method. With specimens containing more than 15% muscovite, the moisture expansion had a peak value when fired between 1000° and 1050°C. At 1050° the magnitude of moisture expansion and moisture uptake was approximately linear with the muscovite content. For specimens with less than 15% muscovite, the variation of moisture expansion with mica content was complex and this was ascribed to the fact that muscovite particles coated with kaolinite behaved differently from bulk mica in the original firing treatment and on subsequent exposure to moisture. The volume percentage of pores greater than 0.2μ in diameter increase as the muscovite content and firing temperature increased and reached a maximum when moisture expansion was at a maximum. The volume percentage of pores less than 0.2μ in diameter decreased under the same conditions but increased slightly in specimens of low muscovite content because the kaolinite reacted on firing with the mica which it coated.