90.60 Close of review Mar 5, 2026
ISO
ISO/TC 226 Materials for the production of primary aluminium
International Standard
71.060.50 Salts
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.
PUBLISHED
ISO 4280:1977
90.60
Close of review
Mar 5, 2026