鉄質沈殿物の熱的性質 [in Japanese] Thermal properties of ferrugineous sinters [in Japanese]
Access this Article
Ferrugineous sinters from various origins and synthetic hydrous ferric oxide were investigated by DTA, TG, and X-ray diffraction techniques and chemical analysis. The samples studied showed an endothermic peak at 100° due to dehydration and an exothermic peak at 850°, possibly due to the formation of α-Fe<sub>2</sub>O<sub>3</sub>. From DTA curve, natural samples can be divided in the following three groups: (1) Those having an endothermic peak at 650°, which is characteristic to the sinters formed at pH's below 5.4. The peak represents the elimination of SO<sub>3</sub>. (2) Those having an exothermic peak at 650°, but without any weight loss. The sinters, high in SiO<sub>2</sub> and/or Al<sub>2</sub>O<sub>3</sub> and formed at pH's above 5.6, belong to this group. (3) Those having exothermic peaks at 650° and 750°. No weight change was recorded for these peaks. The sinters of this group are similar to those the second group in the chemical composition, but low in SiO<sub>2</sub>. The effect of formation pH on thermal behavior of the sinters was also confirmed by synthetic studies.
Chikyukagaku 7.8(1), 1-8, 1974
The Geochemical Society of Japan