Abstract
A new sintering process was proposed which may cope with the increase in the ratio of fine iron ores. The basic concept associated with the new process using double layered mini-pellets (named duplex mini-pellets) was presented. The sintering experiments were conducted by using duplex mini-pellets and the quality of the produced sinter was evaluated by the various physical tests.
(1) Excellent permeability was observed for the sintering bed using the duplex mini-pellets compared with that for the current sinter practice.The bed-permeation resistance was reduced because size and structure of the pellets remained unchanged in the course of sintering before the fusion.
(2) By selecting the low melting region in CaO-Fe2O3 phase diagram as the chemical composition of the shell layer fines (CaO 20 wt%, Fe2O3 80 wt%), the sintering of the duplex mini-pellets was achieved at low temperature around 1230°C.
(3) The sinter produced by the method mentioned above had the texture of primary hematite and binary calciumferrite without secondary hematite.
(4) The sinter having such texture had excellent metallurgical properties, that is to say, low RDI, high JIS RI and good softening and melt-down properties.
