This part of ISO 4687 specifies a molybdenum blue spectrophotometric method for the determination of the phosphorus content of iron ores.
This method is applicable to phosphorus contents between 0,003 % (m/m) and 2 % (m/m) in natural iron ores, iron ore concentrates and agglomerates, including sinter products.
The presence of arsenic, barium or titanium does not affect the result.