アケルマナイト-ゲーレナイト系固溶体中のケイ酸イオンの形態

抄録

The constitutive component of blast furnace slag consisted of solid solution in akermanite (Ca₂MgSi₂O₇) -gehlenite (Ca₂Al (SiAl) O₇) system. The structure, especially structure and distribution of silicate anions in the synthetic solid solution were studied by means of X-ray diffraction, infrared spectroscopy, fluorescent X-ray and trimethylsilylation method.
The complete akermanite-gehlenite solid solution presented when Al³⁺ was continually substituted for Mg²⁺ or Si⁴⁺ in akermanite. Consequently, lattice constant, α continually decreased with changing the component from akermanite to gehlenite. From chemical shifts of Al Ka fluorescent X-ray peaks for compounds of akermanite-gehlenite system as glasses or crystals, the chemical shifts for crystals were fourfold-coordinated Al³⁺ by O^2- but those of glasses showed a tendency to change of coordination number of AP+ from 4 to 6. The quantitative results from structure and distribution of silicate anions by four kinds of trimethylsilylation methods were compared.
It was cleared that Lentz's method gave much better results for high purity akermanite and gehlenite. Also SiO4^4- increased and Si₂O₇^6- decreased with continuous substituting Al³⁺ for Mg²⁺ or Si4+ in akermanite as glasses or crystals. In the case of the same compositions, the structure and distribution of silicate anions in glasses against crystals observed over a wide range of SiO₄^4--Si₄O₁₂^8-. It was found that trimethylsilylation methods were a useful technic for structural analysis of blast furnace slag.