ISO 6676:1993
Acid-grade and ceramic-grade fluorspar; determination of total phosphorus content; reduced-molybdophosphate spectrometric method
- Standard No.
- ISO 6676:1993
- Release Date
- 1993
- Published By
- International Organization for Standardization (ISO)
- Status
- Latest
- ISO 6676:1993
- Scope
- The method specified is based on dissolution of a test portion by fusion with a mixture of sodium carbonate, boric acid and sodium nitrate and subsequent acidification with nitric acid, formation of the molybdophosphate complex and extraction with a mixture of ethyl acetate and butyl acetate, followed by selective reduction of the complex to molybdenum blue by means of tin(II) chloride added to the organic phase, 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 6676:1993 history
- 1993 ISO 6676:1993 Acid-grade and ceramic-grade fluorspar; determination of total phosphorus content; reduced-molybdophosphate spectrometric method
- 1990 ISO 6676:1990 Acid-grade and ceramic-grade fluorspar — Determination of total phosphorus content — Reduced-molybdophosphate spectrometric method
- 1981 ISO 6676:1981 Acid-grade fluorspar — Determination of total phosphorus content — Molybdophosphate photometric method
