다구조형의 차이와 불순물이 카올린광물의 상전이에 미치는 영향: I. 카올리나이트와 딕카이트

Mullitization of kaolinite and dickite was examined with special attention to the influence of polytypism and impurities on the phase transformation. The phase transforation sequence in dickite. Difference in phase transformation above 1000℃ in kaolin minerals is attributed to the different crystal structures of metadickite and metakaolinite on the effect of impurities. A part of quartz is transformaed into cristobalite. Spinel-type phase produced in disordered kaolins including illite occurs over a short range of temperatures. Primary mullite is transformed into orthorhombic mullite at higher temperature as well. These results sustain the idea that disintegration of methkaolin and the spinel-type phase supplies extra sillica and promotes the growth of mullite cristobalite.