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ISO 4280:1977 (R2020)
Cryolite, natural and artificial, and aluminium fluoride for industrial use — Determination of sulphate content — Barium sulphate gravimetric method
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Summary
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.
Notes
90.93 : Norme internationale confirmée
Technical characteristics
| Publisher | International Organization for Standardization (ISO) |
| Publication Date | 11/01/1977 |
| Confirmation Date | 11/03/2020 |
| Edition | 1 |
| Page Count | 3 |
| EAN | --- |
| ISBN | --- |
| Weight (in grams) | --- |
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