Abstract 

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.


General information

  • Status :  Withdrawn
    Publication date : 1981-11
  • Edition : 1
    Number of pages : 5
  • :
    ISO/TC 47
    Chemistry
  • 71.060.30
    Acids

Got a question?

Check out our FAQs

Customer care
+41 22 749 08 88

Opening hours:
Monday to Friday - 09:00-12:00, 14:00-17:00 (UTC+1)

Keep up to date with ISO

Sign up to our newsletter for the latest news, views and product information