Experimental investigation on inducement mechanism of compressive strength of iron ore granule

Granulation experiment was carried out by using four kinds of iron ores, and the compressive strength of granules was measured. Moreover, inducement mechanism of compressive strength of iron ore granule was investigated by adding clay or reagent hematite. The results obtained are follows: (1) From the results of strength measurement of granule made from iron ores which have different kinds of gangue mineral and have different amount of gangue, in the case of Ore A which has little gangue quantity, the wet strength exceeded the dry strength. On the other hand, the dry strength of Ore B, C and D including the gangue minerals exceeded the wet strength. (2) The wet strength of granules was not changed when clay or reagent hematite was added, even if the amount of added clay and reagent hematite increased. It is thought that the effect of gangue mineral and particle size on the wet strength are small, and the adhesion force between particles by liquid bridge is dominant. (3) The dry strength of granule was improved only when clay was added. It is considered that clay mineral and iron ore adhered with electric action when clay mineral and iron ore closed with van der Waals forces range in the process of drying the water because clay mineral was charged negative and iron ore was charged positive.