ISO 9779:1993

Metallurgical-grade fluorspar — Determination of lead content — Solvent extraction atomic absorption spectrometric method

The principle of the method specified is to decompose a test portion by a mixture of nitric, hydrofluoric and perchloric acids, dissolving the salts in hydrochloric acid after evaporation to dryness, extracting the lead from a dilute hydrochloric acid solution of the decomposed test portion into a solution of tri-n-octylphosphine oxide in 4-methyl-2-pentanone, aspirating the extract into the air/acetylene flame of an atomic absorption spectrometer, and measuring the absorbance at 283,3 nm. Applies to products having lead contents in the range 0,0006 % (m/m) to 0,01 % (m/m).