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X‐RAY INVESTIGATION OF THE PYROCHEMICAL CHANGES IN MISSOURI HALLOYSITE *
Author(s) -
Zvanut Frank J.,
Wood Lyman J.
Publication year - 1937
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.1151-2916.1937.tb19898.x
Subject(s) - halloysite , cristobalite , mullite , mineralogy , dehydration , petrography , crystallization , precipitation , materials science , kaolinite , geology , mineral , metallurgy , chemistry , geochemistry , physics , quartz , ceramic , biochemistry , organic chemistry , meteorology
A bstract Results are presented of an X‐ray study of the chemical changes that take place during the progressive firing of Missouri halloysite. A General Electric multiple‐diffraction unit was used to obtain patterns of samples that had been fired at temperatures ranging from 350 °C to the melting point (about 1800 °C) at 50 ° intervals. Twenty‐three of these samples were fired for 12‐hour periods, five for 200‐hour periods, and a few at the higher temperatures for shorter periods of time. The results seem to indicate the dehydration of the kaolin mineral to be near 450 °C, the precipitation of a modified phase of gamma‐alumina at 900 °C, the appearance of mullite at 1150 °C, and the crystallization of cristobalite at about 1350 °C, with its subsequent disappearance above 1500 °C. A short summary of the results of the chemical and petrographic studies which were made with the X‐ray study is appended.