Cryolite, natural and artificial Determination of fluorine content Modified Willard-Winter method

Available format(s)

Hardcopy , PDF , PDF 3 Users , PDF 5 Users , PDF 9 Users

Language(s)

English, French

Published date

01-09-1976

Publisher

International Organization for Standardization

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.

DocumentType	Standard
Pages	6
PublisherName	International Organization for Standardization
Status	Current

Standards	Relationship
BS 5050:1974	Similar to
NBN T 03 433 : 1983	Identical

ISO/TR 4277:2009	Cryolite, natural and artificial Conventional test for evaluation of free fluorides content
PD ISO/TR 4277:2009	Cryolite, natural and artificial. Conventional test for evaluation of free fluorides content