Simple treatment of aluminum dross for odor removal

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21857
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Tohoku University
• Principal Investigator: Hiraki Takehito 東北大学, 工学研究科, 特任准教授 (60550069)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: アルミニウムドロス / 廃棄物 / リサイクル / 水処理 / 悪臭除去 / 硫化水素 / 水酸化アルミニウム

Outline of Final Research Achievements

The recycling and disposal of aluminum dross is extremely difficult due to foul odor and risk of ignition brought about by the reaction between AlN and metallic aluminum in the dross with water to form NH3 and H2 gas. This study investigated hydro-processing of dross to intentionally react dross and water. About 45 g of dross was placed in 450 ml of ultra-pure water at 50 oC and treated for 24 hours. Nitrides and metals in Al dross can be converted to Al(OH)3. Additionally, we focused on the ability of Al(OH)3 to remove H2S as an effective way to utilize hydro processed dross. Therefore, a fundamental study on H2S removal experiment using reagents corresponding to hydro processed dross and its composition phases was conducted. It was found that Al(OH)3, which is the phase present in the hydro processed dross, has the ability to remove H2S with the presence of oxygen, and H2S can be removed as S8.

Free Research Field

環境化学工学

Academic Significance and Societal Importance of the Research Achievements

全国各地でアルミニウムドロスの投棄による環境汚染がいつ起こってもおかしくない状況にあって、本研究にて提案するドロスの湿式処理は、現行システムで利用困難でありドロス問題の核であるメタル分含有率の低いドロスを無害化できる方法となった。湿式処理条件として50oC程度の温水をドロスの質量比で10倍用いることで24時間以内に低品位ドロス中のメタル分と窒化物をほぼ無害化可能である。1000oC以上の高温処理やそれに伴う燃料を使用しない安価な処理であり、本基礎データはドロスの無害化対策に対して直接的に貢献できる成果となった。