1982 年 68 巻 15 号 p. 2207-2214
From the standpoint of mineralogy, mainly morphology of crystal, hematite in self-fluxed sinter is classified into eight types, and it is confirmed that size degradability during the reduction of sinter intensively depends on such morphology. Especially skeletal rhombohedral hematite, which has not been yet described among natural hematite ores, has an extraordinary destructive force during the reduction. Skeletal rhombohedral hematite crystallizes out at a falling temperature stage of sintering reaction when phases of solid magnetite and liquid slag transit into a temperature range of hematite crystallization in phase diagrams, and magnetite changes to hematite abruptly. The more rapid cooling of sintering, the less such hematite and so size degradation during the reduction is improved. Intensive destructive force is considered to be closely related to mineralogical characteristics, those are, skeletal form and locally generation of such crystal groups in state of parallel intergrowth near open pores of sinter. Also one of stable operations applied above principle has been introduced.