Iron powder production - by reduction of fine-grained iron ore, heating the prod. and grinding

摘要

Fe ore is ground to a size of Blaine surface area of ca 1800 cm2/g and pelleted with an organic binder. The pellets are then reduced by a direct process to a 90-99% degree of reduction, so that the C content of the reduced pellets is just sufficient for reducing the residual oxygen in a post-reduction stage in which the pellets are heated in a rotary kiln at 950-1120 degrees C in an H contg. atm. The heat treated pellets are then cooled and ground to about 160 u. The pellets are heated in the rotary kiln in an H2 atm. in which the rate of H2flow is adjusted so that the gas at exit from the kiln has a water vapour content of ca 20%. After grinding of the heat treated pellets a second heat treatment is applied in an H2 atm. at 750 degrees C pref. in a beam furnace.