This International Standard specifies a method for the preparation of predried test samples of natural iron ores, and iron ore concentrates and agglomerates, including sinter products, which are to be used for the determination of analytical values of constituents on a dry basis. The method is not applicable to the following types of ores: a) processed ores containing metallic iron (direct-reduced iron); b) natural or processed ores in which the mass fraction of sulfur is higher than 0,2 %; c) natural or processed ores in which the content of combined water is higher than 2,5 % by mass. NOTE 1 Alternatively, the loss on ignition may be determined as an estimate of the combined water content. Where this method is not applicable, ISO 2596:1994, Iron ores — Determination of hygroscopic moisture in analytical samples — Gravimetric and Karl Fischer methods is used. NOTE 2 A laboratory may elect to use ISO 2596 for all samples to determine the dry sample mass.