| Project/Area Number |
09651027
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
資源開発工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KANEDA Hiroaki Graduate School of Engineering, The university of Tokyo, Professor, 大学院・工学系研究科, 教授 (10092181)
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| Co-Investigator(Kenkyū-buntansha) |
SHOJI Tetsuya Graduate School of Frontier Sciences, The University of Tokyo, Professor, 大学院・新領域創成科学研究科, 教授 (40011093)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | zeolite / clay / analcime / boresilicate glass / geological disposal / high-level radioactive wastes / Sr / Cs / ホウケイ酸塩ガラス / 放射性廃棄物 / 硼珪酸塩ガラス / 蒸気圧 / 加熱 / 生成産物 / ポルサイト / 仮像型 / 風船型 / カオリナイト / イライト / 沸石 / 葉蝋石 / 蝋石鉱床 / 累帯構造 / 流紋岩 / 蘆花鉱床 |
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| Research Abstract |
Clay and zeolite minerals are usually characterized by considerably high adsorption or absorption effect of ions. Exactly, ions and anions are concentrated into mineral by substitution of crystallographic lattice and adsorption or absorption effect on the surface of mineral grains. In the present study some starting borosilicate glasses have been treated experimentally under the hydrothermal condition of a temperature of 200℃ and a vapor pressure of 15.3MPa In particular, the glass constituent elements such as Sr, Cs, Li and B have been examined in derail with respect to chemical behavior and distribution within zeolite formed in the present experiments. The present study program was established in order to apply for the assessment of geological disposal of high-level radioactive wastes. The starting borosilicate glasses consist of the system Na-Cs-Sr-B-Li-Si-Al-O. Experimental study has been performed by hydrothermal treatment of powdered borosilicate glass. The representative mineral
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species obtained in experiments is analcime (NaAlSi206 ・ nH2O) belonging to zeolite group. Na lattice of analcime is substituted usually by Cs element The Cs-bearing and Na-free species is named as pollucite (CsAlSi2O6). Pollucite is characterized by a deficient of H20 within its crystal In addition, the chemical reaction rate tends to decrease with the increase of Cs concentration of analcime. On the contrary, B and Li contribute obviously to progress in crystallization of analcime. The lattice parameter of analcime depends on amounts of Si of 48g site of the crystal, while the parameter doesn't necessarily depend on the contents of alkali or alkali earth elements. However the analcime formed from Li-bearing boroeilicate glass shows the feature of lattice properties larger than the one from Li-free borosilicate glass. Considering the charge balance of the crystal Li has to occupy the crystallographic lattice. The analcime formed from Sr-free borosilicate glass scarcely includes B, and the analcime formed from B-free borosilicate glass contains little Sr. It is concluded that the formation of Sr-bearing analcime should need necessarily B. Less
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