ISO-1693 › Cryolite, natural and artificial -- Determination of fluorine content -- Modified Willard-Winter method
The following bibliographic material is provided to assist you with your purchasing decision:
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.
To find similar documents by classification:
This document comes with our free Notification Service, good for the life of the document.
This document is available in either Paper or PDF format.
Document Number
ISO 1693:1976
Revision Level
1ST EDITION
Status
Current
Publication Date
Sept. 15, 1976
Committee Number
ISO TC 47/SC 7