Boron contamination from platinum crucibles

Abstract

38SHORT NOTES spectrum (below) of the product obtained after 16 days of ageing. That the reaction is still not complete is indicated by the broad band around 22 ~ 20 on the X-ray trace, (CuK~ radiation). This appears to be the first time that the crystallization of kaolinite is realized at such a low temperature from an amorphous material and in an almost neutral solution. It is thought that the transformation occurs through an undetectable "zeolitic" phase, which readily forms at high pH and facilitates the subsequent crystallization into kaolinite under neutral conditions. The direct transformation from the gel into a clay mineral using an acid solution or water is not feasible as it has been shown (De Kimpe, 1967) that under these conditions, the final products are pseudo-boehmite and an amorphous alumino-silicate with a different composition.Further experiments are in progress to investigate in more detail this reaction, and a complete report will be given later.