ISO 10203:1992

The method is based on decomposition of the test portion by hydrochloric acid/nitric acid, evaporation, ignition of the residue and removal of silica, fusion with sodium carbonate and dissolution of the cooled melt in the filtrate, aspiration of the solution into the flame of an atomic absorption spectrometer, and comparison of the absorbance values obtained for calcium with those obtained from the calibration solutions. Applies to calcium contents between 0,01 % and 10,0 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products.