Status : Published (Under review)

This standard was last reviewed and confirmed in 2020. Therefore this version remains current.
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Abstract

Phosphorus content can be determined in the range of 0,001 % (m/m) to 0,025 % (m/m). Cr(III) and silica cause interference which is eliminated. The principle is dissolution of a test portion in a mixture of nitric and hydrochloric acids, fuming with sulfuric acid, oxidation of Cr(III) to Cr(VI), precipitation of Fe(III) phosphate and redissolution of the precipitate, addition of boric, tartaric and sulfamic acids, formation and extraction of molybdophosphoric acid, reduction of the heteropoly acid to molybdenum blue and back-extraction into an aqueous phase, measurement of the absorbance of the aqueous solution at 700 nm.

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General information

  • Status
     : Published
    Publication date
     : 1992-08
    Stage
    : International Standard confirmed [90.93]
  • Edition
     : 1
    Number of pages
     : 6
  • Technical Committee :
    ISO/TC 155
    ICS :
    77.120.40 
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