ISO 1693:1976
Cryolite, natural and artificial — Determination of fluorine content — Modified Willard-Winter method
OVERVIEW
Specifies the determination for natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The principle consists in fusion of a test portion with sodium carbonate, separation of fluorine by distillation with sulphuric acid or perchloric acid. Titration with thorium nitrate solution in presence of sodium alizarinsulphonate/methylene blue as indicator. Alternatively, the thorium nitrate titration may be made using only sodium alizarinsulphonate, the end-point being*spectrophotometrically determined at 525 nm.
COMMENTS
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PRODUCT DETAILS
| Status | Current |
|---|---|
| Edition | 1976 |
| No. of Pages | 6 |
| ICS Classification | 71.060.50 Salts |
| Committee | ISO/TC 226 |
| Available for Purchase | For sale in Singapore only |
| Adoption | ISO |