Glass decomposition by hydrofluoric acid and perchloric acid under atmospheric pressure

Abstract

The experimentally verified glass decomposition procedure using HF and HCIO₄ acids in platinum dishes under atmospheric pressure is described. This procedure provides relatively low and reproducible amounts of fluorine and Silicon ions in the reaction products. These have been identified as potentially interfering ions during the following treatment of the decomposed sample and therefore, they are chosen as criteria for the evaluation of the quahty and reliability of the decomposition process. The decomposition procedure suggested differs from those published before especially in respect of concentrations, volumes and rates of decomposition acids per 1 g of sample. The weight of the decomposed sample and the matrix composition should also be considered. The formation of soluble, relatively stable (undissociated) or barely soluble "secondary phases" in reaction products is caused by unfavourable decomposition conditions, in most cases. This fact is presented by the example of X-ray diffraction of barely soluble reaction products isolated from HF-HCIO₄ decomposition of low alkah oxides-lime-alumina-magnesia-borosilicate glass, type E.