Reference number
ISO 9438:1993
ISO 9438:1993
© ISO 2025
ISO 9438:1993
Metallurgical-grade fluorspar — Determination of total phosphorus content — Reduced-molybdophosphate spectrometric method
Edition 2
1993-03
1993-03
Withdrawn
Abstract
The principle of the method specified is to decompose a test portion by alkaline fusion and subsequent dissolution of the melt in excess of nitric acid, precipitation of iron(III) phosphate with ammonia solution, dissolution of the precipitate in nitric acid, formation of the molybdophosphate complex and extraction, followed by selective reduction of the complex to molybdenum blue, spectrometric measurement of the absorbance of the coloured complex at the wavelength of maximum absorption (about 710 nm). Applies to products having total phosphorus contents, expressed as PO4^3-, in the range 0,01 % (m/m) to 1,0 % (m/m).
Life cycle
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Previously
WithdrawnISO 9438:1989
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Now