This International Standard specifies a flame atomic absorption method for the determination of the manganese content of aluminium oxide primarily used for the production of aluminium. The method is applicable to products of which the manganese content, expressed as Mn, is between 0,000 2 and 0,005 % (m/m) (0,000 258 and 0,006 46 % (m/m), expressed as MnO). NOTE — If the apparatus available does not have a sufficient sensitivity for the lower contents of manganese, it is recommended that there should be prior extraction of the manganese, by the method specified in annex A.