Attempted Low-Temperature Syntheses of Kaolin Minerals
Abstract
ALTHOUGH kaolin minerals appear to be formed in Nature under acidic conditions at relatively low temperatures and low water-vapour pressures, their synthesis in the laboratory under similar conditions has been found exceptionally difficult. It appears that a proper choice of many variables is essential. In previous investigations1,2, individual kaolinite crystals have been obtained by ageing mixed alumina and silica gels for 2 months at 100° C. and under pH. conditions around 4.5, but the crystalline yield was extremely poor and the kaolinite could be proved only by single-crystal, electron diffraction methods ; X-ray diffraction failed to detect the small yield. It seems that the ready polymerization of silica, with aluminium incorporated in the structure, inhibited the crystallization of a layer structure. Similar difficulties are not encountered in forming hydrous magnesian silicates.
- Publication:
-
Nature
- Pub Date:
- April 1961
- DOI:
- 10.1038/190254a0
- Bibcode:
- 1961Natur.190..254B