A higher bustle temperature in midrex direct reduction process is always desirable due to its positive effect on the productivity and DRI quality. The limit of the bustle temperature is related to the sticking or clustering behaviour of oxide pellets during the reduction in the reactor. It has been well estabilished that coating of oxide pellets by a refractory material decreases its
tendency to clustering. In this study, the clustering behaviour of oxide pellets (produced from Golegohar-Chadormalu iron ore) during redution at different temperatures was investigated. The effect of coating with different amounts of hydrated lime on the clustering behaviour was also examined. Microscopic examination of coated pellets shows a porous, non-continious layer of Ca(OH)2 being fromed on the surface of the pellets. The clustering tendency of coated pellets, measured by the standard sticking test at pilot scale, was much lower, compared with normal (uncoated) pellets, while their reducibility was the same.


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