Numéro de référence
ISO 5438:1993
ISO 5438:1993
© ISO 2024
ISO 5438:1993
Spaths fluor pour la fabrication de l'acide fluorhydrique et spaths fluor utilisables dans l'industrie céramique — Dosage de la silice — Méthode spectrométrique au molybdosilicate réduit
Edition 2
1993-03
1993-03
Annulée
Résumé
The method specified is based on decomposition of a test portion by fusion with sodium carbonate and subsequent acidification with hydrochloric acid in the presence of boric acid to complex fluoride, formation of the molybdosilicic acid complex and selective reduction to the blue molybdosilicic acid complex with addition of tartaric acid to prevent interference from phosphate, spectrometric measurement of the absorbance of the coloured complex at the wavelength of maximum absorption (about 795 nm). Applies to products having silica contents, expressed as SiO2, in the range 0,05 % (m/m) to 4,0 % (m/m).
Cycle de vie
-
Précédemment
AnnuléeISO 5438:1985
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Actuellement