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Influence of Impurities on High‐Temperature Reactions of Kaolinite
Author(s) -
JOHNSON SYLVIA M.,
PASK JOSEPH A.,
MOYA JOSE S.
Publication year - 1982
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.1151-2916.1982.tb09918.x
Subject(s) - cristobalite , exothermic reaction , mullite , differential thermal analysis , kaolinite , impurity , crystallization , materials science , phase (matter) , mineralogy , analytical chemistry (journal) , chemistry , metallurgy , chromatography , optics , diffraction , organic chemistry , ceramic , quartz , physics
When kaolinite is heated for differential thermal analysis (DTA) the second exothermic peak (∼1275°C) is due to growth of mullite crystals accelerated by formation of a liquid phase. The third exothermic peak (∼1460°C) is due to crystallization of cristobalite. Addition or presence of impurity oxides causes the second peak to shift in temperature and accelerates the formation of cristobalite so that the third peak may appear as low as the second exothermic peak temperature.