Reclamation of irradiation contaminated soil by supercritical fluid washing technique

汚染土壌の超臨界CO洗浄法による減容効果

石山 新太郎; 神谷 昌岳*; 近藤 充記*

Ishiyama, Shintaro; Mamitani, Masataka*; Kondo, Mitsunori*

福島県における汚染土壌の洗浄・減容化のため実用化開発を進めている水洗浄法による性能実証フィールド試験を界面化学的分散制御/高せん断流解先洗浄実機スケールダウンプラントにより実施し、工学的データベースを構築するとともに、本データをもとに界面化学的分散制御/高せん断流解先洗浄実機プラント及び超臨界CO洗浄法を適用した場合の性能検討を行った結果、下記結果が得られた。水洗浄の場合、37000Bq/kgの汚染土壌の洗浄を行い全体の85%を再生土化できた。(2)洗浄後の洗浄度の汚染濃度で500Bq/kgを達成した。(3)天然モルデナイトが主要な汚染源鉱物である。

Contaminated soil washing verification test was planted on the base of engineering database obtained by our previous report and implemented in Fukushima for the purpose of performance verification of irradiation contaminated soil washing scale-down plant. Chemical interface controlled dispersion approach and high-speed shearing water washing and supercritical CO washing techniques were applied to wash highly contaminated soil over 10,000 Bq/kg at moor and the following results were obtained. (1) Over 85% volume reduction of contaminated soil and condensation up to 37,000 Bq/kg were achieved in the volume reduction process. (2) The collection rate of reclamation soil under 500 Bq/kg after washing process reached up to 30% and to be enhanced through the improvement of retention of soil in the process. (3) Mineral mordenite contained in contaminated soil is one of main contaminant source.