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Optical Spectra of Nickel‐Bearing Silicate Gels Prepared by the Geopolymer Technique, with Special Reference to the Low‐Temperature Formation of Liebenbergite (Ni 2 SiO 4 )
Author(s) -
Onikura Kyoichi,
Nakamura Yoshinori,
Vedanand Swaroop
Publication year - 2001
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.1151-2916.2001.tb00904.x
Subject(s) - crystallization , cristobalite , thermogravimetry , silicate , nickel , materials science , differential thermal analysis , amorphous solid , sol gel , chemical engineering , thermal analysis , sodium silicate , inorganic chemistry , chemistry , thermal , metallurgy , organic chemistry , quartz , diffraction , engineering , physics , optics , meteorology , nanotechnology
A nickel‐bearing silicate gel was prepared from sodium disilicate and nickel nitrate solutions at room temperature. Then, the gel was heat‐treated in air up to 800°C at intervals of 200°C. The products were completely amorphous after heating at ≤600°C. However, liebenbergite and cristobalite were identified as products of the crystallization of the gel after heating at 800°C. The polycondensation process of the gel was discussed based on X‐ray diffractometry, thermogravimetry‐differential thermal analysis, and optical spectroscopy, to clarify the easy crystallization of the gel to liebenbergite and cristobalite. The present technique is very useful for the low‐temperature preparation of liebenbergite, which has potential application in the decomposition catalysis of chlorofluorocarbons, in connection with the problem with the ozone layer.