カオリナイトと酸化鉄(II)の高温での固相反応の機構論的研究

概要

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A mechanistic investigation of the solid-state reaction occurring in the mixture of kaolinite and ferric oxide heated in a mildly reducing atmosphere at 900-1300℃ was performed, and the following reaction scheme was postulated. Above 950℃, FeO reacted with Al_2O_3 in both the spinel phase (SiO_2・6Al_2O_3) and the amorphous phase (6SiO_2・Al_2O_3) which were formed as the result of phase separation of metakaolin to produce hercynite (FeAl_2O_4). This extraction of Al_2O_3 from the amorphous phase should decrease the Al content. The mineralizing action of FeO caused the crystallization of quartz solid solution from the SiO_2-enriched amorphous phase. On the other hand, the spinel phase which lost a considerable amount of Al_2O_3, also due to the formation of hercynite, yielded mullite. Concentration analyses by electron spectroscopy for chemical analysis (ESCA) combined with the Ar etching treatment for Al, Si and Fe revealed that, during the above solidstate reaction, migration of Al toward FeO grains occurred.
社団法人日本セラミックス協会の論文
2000-10-01