Laser Alumina Reduction Group

Laser-induced reduction of alumina from moon resources

Introduction

Welcome to our research group.
This is the website of “Alumina Reduction group” of the Komurasaki Lab belonging to The University of Tokyo. We have been conducting research on new method of aluminum reduction toward lunar resources utilization.

Background

Currently, plans for construction of lunar bases are being formulated by various institutions. And also in Japan, JAXA has a project for lunar base construction in about 20 years as a space exploration policy.
Utilization of lunar resources is one of the possible ways to obtain their metallic material and oxygen which is necessary for sustainable life on the moon. By producing metal and oxygen on the moon without relying on transportation from the earth, the costs and time can be reduced. Such a concept is called ISRU (In Situ Resource Utilization).

Thus, our research team is researching a method to reduce alumina using a laser. It accounts for 25% of the moon resources and aluminum is the most common metal element. This method consumes only the power that can be produced on the moon, and can produce aluminum and oxygen without relying on transportation from the earth.


Mechanism of Reduction

The direction in which a redox reaction proceeds is determined by the pressure and temperature. The relationship is shown by a graph called Ellingham diagram like the figure on the left. The vertical axis shows Gibb's free energy, and with the value larger than 0, the reduction reaction proceeds. It can be known from this graph that about 4000 ℃ is required for reduction reaction of alumina.


Reduction Method Using Laser Sustained Plasma

We had been researching a method of reducing powdery alumina using heating by the plasma generated by the laser. This plasma is called LSP, which stands for Laser Sustained Plasma. The temperature of the central area of LSP is about 15000 ℃ and it heats alumina at this quite high temperature.
Although this method succeeded in reducing alumina, the energy efficiency was low because much of laser energy was used to maintain LSP. Therefore, in order to improve the efficiency, we are currently researching reduction by another method.



Reduction Method Using Laser Ablation

We are currently researching reduction methods using laser ablation.
The laser is focused on solid alumina and it is heated instantaneously by high density energy. With this method, higher energy efficiency can be expected because the alumina is directly heated by laser without LSP. As shown in the photo, heated alumina spouts gas in a cylindrical shape and emits light intensely. This phenomenon is called ablation.

This method also succeeded in reducing aluminum oxide. In the future, we will conduct research on efficiency measurement and construction of a collection system of aluminum and oxygen produced.



Test Chamber

The laser passes the window on the right side in the photo to heat alumina placed in the chamber.
There are multiple observation windows on the side of the chamber, which allow us to measure spectra and take pictures inside the chamber.

This new chamber was set in 2021.
The size was 10 times as large as that of the previous chamber, and the number of observation windows are increased to three.
Aluminum collection experiments with complicated system have benn conducted by using this new chamber.


CO2 Laser

Our CW CO2 laser has the power of 2 kW. The laser beam irradiated from this device is focused on the alumina rod by ZnSe convex lens after the beam radius is expanded.

Product number:YB-2000B7 （Panasonic）


Journal Paper
Laser spot size and preheating effects on alumina reduction using laser ablation,
Seiya Tanaka, Shin Yamada, Kimiya Komurasaki, and Hiroyuki Koizumi, Journal of Thermophysics and Heat Transfer, Published online, (2020).

Characterization of Reduction Products Generated by Laser Ablation of Alumina,
Shin Yamada, Seiya Tanaka, Kimiya Komurasaki, Rei Kawashima, and Hiroyuki Koizumi, Vacuum, Journal of IAPS, Vol.26 (2018), No.1, pp. 33-38.

Alumina reduction by laser ablation using a continuous-wave CO2 laser toward lunar resource utilization,
Seiya Tanaka, Shin Yamada, Kimiya Komurasaki, Rei Kawashima, and Hiroyuki Koizumi, Vacuum, (2017).

Alumina Reduction by Coupling Laser Ablation and Laser Sustained Plasma,
Soichiro SANO, Ryota SOGA, Maximillian Frank, Kimiya KOMURASAKI, Hiroyuki KOIZUMI, and Tsuruo KOBAYASHI, Frontier of Applied Plasma Technology, Vol.9 (2016), No.2, pp. 49-54.

Alumina reduction by laser sustained plasma for aluminum-based renewable energy cycling,
Makoto Matsui, Naohiro Fukuji, Masakatsu Nakano, Kimiya Komurasaki, Yoshihiro Arakawa, Tetsuya Goto, Hirofumi Shirakata, J. Renewable Sustainable Energy 5, 039101 (2013).

発光分光によるレーザープラズマ風洞気流の気流特性とアルミナ還元効率の評価,
福路直大、松井信、山極芳樹、中野正勝、小林明、小紫公也、荒川義博、後藤徹也、白形弘文, プラズマ応用科学 Vol.21, No. 1, (2013) pp. 47-50.

International Conference
Aluminum Collection by Heterogeneous Condensation in Alumina Laser Reduction for Lunar Regolith,
Seiya Tanaka, Shin Yamada, Kimiya Komurasaki, and Hiroyuki Koizumi, The 2020 AIAA Propulsion and Energy Forum, online, August, (2020).

Effect of Preheating in Alumina Reduction using Laser Ablation Toward Utilization of Lunar Resources,
Seiya Tanaka, Shin Yamada, Kimiya Komurasaki, Rei Kawashima, and Hiroyuki Koizumi, The 2019 AIAA Propulsion and Energy Forum, Indianapolis, America, August, (2019).

Aluminum Collection at Close Range from Laser Ablated Alumina toward Aluminum Smelting from Lunar Regolith,
Shin Yamada, Seiya Tanaka, Kimiya Komurasaki, Makoto Matsui, Rei Kawashima, and Hiroyuki Koizumi, 32nd ISTS, Fukui, Japan, June, (2019).

Alumina Reduction by Laser Ablation Using a Continuous-Wave CO2 Laser Toward Aluminum Energy Cycle,
Seiya Tanaka, Shin Yamada, Kimiya Komurasaki, Makoto Matsui, Rei Kawashima, and Hiroyuki Koizumi, The 2018 AIAA Propulsion and Energy Forum, Ohio, America, July, (2018).

Alumina Reduction by Laser Ablation Towards Use of Moon Resources,
Seiya Tanaka, Soichiro Sano, Ryota Soga, Kimiya Komurasaki, Hiroyuki Koizumi, and Rei Kawashima, Vacuum, The 11th International Symposium on Applied Plasma Science, Warsaw, Poland, September, (2017).

Domestic conference in Japan
月資源レーザー還元法におけるレーザー照射アルミナ表面でのアルミニウム粒子生成,
田中聖也, 田中直輝, 小紫公也, 小泉宏之, JASMAC日本マイクログラビティ応用学会第32回学術講演会, オンライン, 2020年10月.

レーザーアルミナ還元におけるジルコニア混合によるプルーム温度上昇効果,
田中聖也, 佐藤彰太, 山田慎, 小紫公也, 小泉宏之, 日本航空宇宙学第51期年会講演会, COVID-19により中止, 2020年4月.

月面でのレーザーアルミナ還元に向けたレーザースポット径拡大の効果,
田中聖也, 山田慎, 佐藤彰太, 小紫公也, 小泉宏之, 第63回宇宙科学技術連合講演会, 徳島県, 2019年11月.

月面でのアルミナ還元に向けたアブレーションガス温度のレーザースポット径依存性の計測,
田中聖也, 山田慎, 小紫公也, 小泉宏之, 日本航空宇宙学会第50期年会講演会, 東京都, 2019年4月.

レーザーアブレーションを用いたアルミナ還元における試料予加熱によるエネルギー変換効率向上,
田中聖也, 山田慎, 小紫公也, 小泉宏之, 一般社団法人レーザー学会学術講演会第39回年次大会, 東京都, 2019年1月.

レゴリスからのアルミニウムおよび酸素の獲得を目指したCWレーザーアブレーションによるアルミナ還元,
田中聖也, 山田慎, 小紫公也, 小泉宏之, 川嶋嶺, 日本航空宇宙学会第49期年会講演会, 東京都, 2018年4月.

Alumina reduction by CW laser ablation towards metal recovery from regolith,
田中聖也, 山田慎, 小紫公也, 小泉宏之, 川嶋嶺, 第37回宇宙エネルギーシンポジウム, 神奈川県, 2018年3月.

Master thesis
2019
アルミナレーザー還元における生成アルミニウムの不均一凝縮核生成による回収
2018
レーザーアブレーションアルミナ還元手法における試料予加熱による還元率向上
2011
レーザー維持プラズマを用いたアルミナ還元技術に関する研究

Bachelor thesis
2020
レーザー加熱を⽤いたアルミナ還元におけるアルミニウム粒析出・蒸着現象の研究
2019
ジルコニア混合によるレーザーアルミナ還元率向上
2017
アルミナのレーザーアブレーションにより生ずるAl-O系プルームの回収板付着実験
2016
月資源利用を目指したレーザーによるアルミナアブレーション還元実験
2015
レーザー維持プラズマによるアルミナアブレーションガスの還元実験
2014
CO2連続レーザーによるアブレーション実験
2013
レーザーアブレーションによるアルミナ還元の基礎研究

Joint Group
Japan EXpert Clone Corporation　2012.1.1.-　「プラズマジェットによる酸化アルミニウム還元技術」
Aluminum Energy Cycle Study Group


Shizuoka University Matsui Laboratory
Tokyo Metropolitan College of Industrial Technology Nakano Laboratory

KAKENHI
Grant-in-Aid for challenging Exploratory Research　2017-06-30 – 2020-03-31 「月資源利用を目指した先進的アルミナ還元技術の研究」
Grant-in-Aid for challenging Exploratory Research　2014-04-01 – 2017-03-31 「レーザープラズマ風洞を用いた革新的アルミナ還元技術」


Aluminum Energy Cycle

Alumina reduction using laser is useful not only on the moon but also on the earth.
Natural energy power generation, which does not discharge carbon dioxide, is not used so much because of its instability. herefore, we have an idea that the generated energy is stored in the form of aluminum by reducing alumina with a laser using surplus energy. Energy can be extracted by burning aluminum or forming hydrogen from reaction of aluminum and water. Thus, the laser reduction of aluminum oxide can stabilize the natural energy power generation.
This cycle of storage and utilization of energy mediated by aluminum is called aluminum energy cycle.

Click here for the HP of Aluminum Energy Cycle study group.


CW Laser Propulsion

We used to research CW laser propulsion.
A brief description of the CW laser thruster. Here, CW laser means Continuous Wave = continuous wave laser. There are other types of lasers that oscillate like pulses. Details are here.
This propulsion unit is an organization that receives the laser emitted from the earth and satellites and converts it into energy. There are many ways to convert a laser into energy, but we were researching how to make a plasma from a laser (LSP) and heat the propellant with it.
The photo on the right is a photo during the operation test of the propeller manufactured in the laboratory.


Plasma Wind Tunnel

We also researched application of the exhaust jet of the laser propulsion unit for a wind tunnel.
When a space shuttle re-enters the atmosphere, the surface is heated violently. A device that blows a wind on a vehicle to simulate such influence of gas around the body of the vehicle on the ground is called a wind tunnel. Here are details.