ISO 9438:1993
Metallurgical-grade fluorspar; determination of total phosphorus content; reduced-molybdophosphate spectrometric method
- Standard No.
- ISO 9438:1993
- Release Date
- 1993
- Published By
- International Organization for Standardization (ISO)
- Status
- Latest
- ISO 9438:1993
- Scope
- 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<(hoch)3->, in the range 0,01 % (m/m) to 1,0 % (m/m).
ISO 9438:1993 history
- 1993 ISO 9438:1993 Metallurgical-grade fluorspar; determination of total phosphorus content; reduced-molybdophosphate spectrometric method
- 1989 ISO 9438:1989 Metallurgical-grade fluorspar — Determination of total phosphorus content — Reduced molybdophosphate spectrometric method
