Research on Advanced Alumina Reduction Technology for Lunar Resources Utilization

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18935
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Aerospace engineering, Naval and maritime engineering, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: KOMURASAKI KIMIYA 東京大学, 大学院工学系研究科(工学部), 教授 (90242825)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 航空宇宙工学 / エネルギー全般 / プラズマ / レーザー / アルミニウム

Outline of Final Research Achievements

I studied the technology that reduces aluminum oxide (alumina)　and separates it into aluminum and oxygen by using laser ablation of alumina sintered rod. First, the laser intensity on the surface of the sintered rod and the area occupancy of the laser spot were optimized, and the theoretical maximum ablation rate (42 mg/s) was achieved. Next, an attempt was made to improve the ablation plume temperature upper limit (superheat limit temperature) by using an alumina/zirconia mixture, but it was found that this combination has a positive azeotrope, and the temperature did not rise. Finally, by observing the state of aluminum deposited on the surface of the sintered rod for the recovery of aluminum and examining the analysis and optimization of theoretical precipitation conditions, the surface temperature of the recovery system needs to exceed the aluminum melting point.

Free Research Field

航空宇宙工学

Academic Significance and Societal Importance of the Research Achievements

提案するアルミ製錬技術が完成すると月面における長期有人活動に道を開くことができる。また水素貯蔵技術・サイクルとしても画期的であり、アルミ燃料輸送の方が液体水素輸送よりも安全で効率的なこともあり、温室化ガスを排出しない航空機や船舶用燃料としても期待でき、月面、宇宙ステーション、地上、極地などにおいて、太陽光と水のみの環境でエネルギーサイクル（エネルギーの備蓄と発生）を構築することもできる。