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ISO 1694:1976

Cryolite, natural and artificial — Determination of iron content — 1,10- Phenanthroline photometric method

Sep 1, 1976

General information

90.60     Mar 5, 2026

ISO

ISO/TC 226

International Standard

71.060.50  

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Scope

Applies for the determination of natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The method is applicable to products having an iron content equal to or greater than 0,020 % (m/m). The principle consists in dissolution of a test portion by either alkaline or acid fusion. Reduction of iron(III) with hydroxylammonium chloride, formation of the complex iron(II)-1, 10-phenathroline in a buffered medium at pH value between 3,5 and 4,2. Photometric measurement of the coloured complex at a wavelength of about 510 nm. Applies ISO Recommendation R 1694-1970.

Life cycle

NOW

PUBLISHED
ISO 1694:1976
90.60 Close of review
Mar 5, 2026

National adoptions

Cryolite, natural and artificial — Determination of iron content — 1,10- Phenanthroline photometric method

95.99   Withdrawal of Standard

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