R2: Crystal structure, crystal chemistry, physical properties of minerals, crystal growth and applied mineralogy

[R2P-09] Synthesis Condition and Iron Valence in Vivianite

「発表賞エントリー」

*Kohei Chiba¹, Eriko Ohshima², Misaki Takahashi³, Kazumasa Sugiyama⁴ (1. NIT Ichinoseki Col., Adv. Chem. Eng., 2. NIT Ichinoseki Col., Dept. Eng. Fut. Innov., Div. Chem. Eng. & Bio., 3. NIT Ichinoseki Col., Dept. Chem. Eng., 4. Tohoku Univ., IMR)

Keywords:Vivianite, Metavivianite , Iron Phosphate

Vivianite is known as an iron (II) phosphate octa hydrate. Metavivianite is known as the oxidized vivianite. They are unearthed together. However, the mechanism of forming metavivianite is unknown. To resolve the thing, we synthesized iron phosphate in virous temperature conditions and analyzed their crystal structures. As a result, we discovered metavivianite obtained in 60 degrees. Above 70 degrees, vivianite and metavivianite are not obtained. It's considered that metavivianite is the metastable phase because it's obtained in a narrow temperature range.