Reference number
ISO 4280:1977
ISO 4280:1977
© ISO 2025
International Standard
ISO 4280:1977
Cryolite, natural and artificial, and aluminium fluoride for industrial use — Determination of sulphate content — Barium sulphate gravimetric method
Edition 1
1977-11
1977-11
ISO 4280:1977
10120
Published
(Edition 1, 1977)
This publication was last reviewed and confirmed in 2020.
Therefore this version remains current.
Abstract
Applicable to products having a content, expressed as sulphur trioxide, equal to or more than 0.1 % (m/m). Bases on alkaline fusion of a test portion with a mixture of sodium carbonate and boric acid. Extraction of the fused mass with perchloric acid solution and precipitation of the sulphate ions with barium chloride in an acidified medium. Filtration on a fine-texture, ashless filter paper (pore diameter approximately 0.4 to 1.0 m). Calcination after drying in an electric oven at (850 20) °C. Weighing of the residue.
General information
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Status: PublishedPublication date: 1977-11Stage: International Standard confirmed [90.93]
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Edition: 1Number of pages: 3
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Technical Committee :ISO/TC 226ICS :71.060.50
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