ISO 2598-2:1992

The method is based on decomposition of the test portion by fusion with sodium tetraborate and treatment with dilute nitric acid, addition of ammonium molybdate to convert silicate into a molybdatosilicate complex, reduction to molybdenum blue with ascorbic acid, and spectrophotometric measurement of the absorbance of the molybdenum blue complex at a wavelength of approximately 600 nm. Applies to silicon contents between 0,1 % and 5,0 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products, especially for ores containing fluorine.