2022 Fiscal Year Final Research Report
Magnetic classification of radioactive Cs-polluted soil using formation of magnetite
Project/Area Number |
20H04365
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 64020:Environmental load reduction and remediation-related
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Research Institution | Prefectural University of Hiroshima |
Principal Investigator |
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Co-Investigator(Kenkyū-buntansha) |
片山 裕美 八戸工業大学, 工学部, 講師 (30823661)
奥田 哲士 龍谷大学, 先端理工学部, 教授 (60343290)
水原 詞治 龍谷大学, 先端理工学部, 講師 (70638999)
澤田 剛 鹿児島大学, 総合科学域共同学系, 准教授 (90240902)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 磁力選別 / 分級 / 放射性セシウム / 減容化 / マグネタイト / 除染 |
Outline of Final Research Achievements |
Since radioactive cesium is strongly trapped inside clay in soil, the development of techniques for classifying the clay fraction in contaminated soil is an urgent matter. Under these circumstances, we developed our new method by mixing a divalent iron/alkali agent with the contaminated soil heating to simultaneously generate a magnetic substance and thermally reduce the volume at 250°C. Using FeSO4 7H2O as a magnetic material and NaOH as an alkaline agent and applying the above-mentioned developed technology to black soil (containing 23% organic matter), it was found that a maximum of 11.8% of the treated soil could be magnetically separated under moderate heating conditions. Moreover, we clarified the conditions for suppressing the formation of secondary particles with unburned carbon, which is abundant in residual soil, as a binder between fine soil particles, and found that magnetic substances are preferentially generated and adsorbed on specific soil components.
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Free Research Field |
環境化学
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Academic Significance and Societal Importance of the Research Achievements |
先行する湿式除染法においても,有機物含有土の除染は不得手で,加熱分離法に期待が集まるものの廃棄物量の削減などに課題が残る。そこで本研究では,機能性マグネタイトが湿式合成されることに注目し,鉄系イオン種を土壌粒子表面に付着させ,次いでアルカリ処理し,続いて加熱しマグネタイトを生成させた。これにより,熱減容プロセスにより有機物を減容し,同一反応場でマグネタイトを生成させ,連続的に磁選により分級するシステムとした。本手法は,加熱温度の最小化,前処理工程の簡略化,選択性向上の可能性(2:1型粘土鉱物を標的),総廃棄物量の削減により処理コストも同等に抑えられる見込みである。
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