ISO 848:1981 PDF
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Phosphoric acid for industrial use — Determination of calcium content — Titrimetric method
The general method is applicable to phosphoric acid not containing polyphosphoric acids and to products having a calcium content equal to or greater than 0.020 % (m/m). In special cases a preliminary hydrolysis of polyphosphoric acids is carried out by prolonged boiling in the presence of hydrochloric acid. Precipitation of calcium as calcium oxalate at pH 4 0.3, filtration of the precipitate, dissolution in hydrochloric acid and re-precipitation under the same operating conditions in order to purify the precipitate. Oxidimetric titration in sulphuric acid solution by means of potassium permanganate. – Cancels and replaces ISO Recommendation R 848-1968.
Edition | 1981 |
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Published Date | 1981 |
Published By | International Standardization Organisation |
Page Count | 5 |