ISO 4277:1977 PDF
Cryolite, natural and artificial — Conventional test for evaluation of free fluorides content
Cryolite, natural and artificial — Conventional test for evaluation of free fluorides content
- Статус документа:
- Отменён
- Формат:
- Электронный (PDF)
- Количество страниц:
- 3
- Дата публикации:
- 1 ноября 1977 г.
- Издание:
- ISO IS 4277 edition 1 version 1
- ICS:
- 71.060.50
Applicable to products having contents of AlF3 of more than 0.15 % (m/m) or of NaF of more than 0.4 % (m/m). Covers sintering of a test portion with a known quantity of sodium fluoride in a muffle furnace at a temperature of (790 10) °C. Under these conditions, aluminium fluoride in excess of that required by the stoichiometric formula AlF3 .3NaF reacts to form cryolite; extraction of the ground sintered mass with boiling water. Acidification with hydrochloric acid solution to a pH less than 3.7 and titration of the excess sodium fluoride with thorium nitrate solution in the presence of alizarin-S as indicator. Has also been approved by the IUPAC.
Технические детали
- Технический комитет
- ISO/TC 226 - Materials for the production of primary aluminium
- SKU
- ISO 4277:1977