This method ist applicable to a concentration range of 0,05 to 10 % (m/m) of combined water in natural iron ores, and iron ore concentrates and agglomerates including sinter products. The term combined water means that part of the water content of an iron ore that can be removed only at temperatures substantially higher than 100 to 110 °C. Figures show the general arrangement of the test apparatus for the Karl Fischer measurement, the heating tube, and the absorption cell. Includes three annexes.