講演情報
[PPS02-P22]Reduction of FeO under ultra-high vacuum conditions simulated lunar surface
*遠山 晃太1、清末 雅人1、菊地 紘1、清宮 優作1、渡邉 匡人1、小林 真輝人2、清水 雄太2、竹村 知洋2、宮本 英昭2 (1.学習院大学、2.東京大学)
キーワード：
ISRU、鉄抽出実験、高真空環境
In recent years, the development of technologies related to the In-Situ Resource Utilization has become increasingly important. In modern steelmaking, the reduction of iron ore using carbon or hydrogen is commonly employed. However, for iron extraction on the lunar surface, a reduction-agent-free method utilizing an ultra-high vacuum environment is effective, and it is advantageous from the perspective of transporting planetary environmental protection as it involves no material transfer from Earth.
This study investigated the conditions for extracting iron from FeO without reductants by exploiting the ultra-high-vacuum environment of the lunar surface and conducted iron extraction experiments under vacuum conditions. The temperature conditions for extracting Fe from FeO were calculated across a pressure range of 10-1 Pa to 10-12 Pa by thermodynamic equilibrium calculation. From the calculations, it was found that FeO is in equilibrium in four phases-FeO(s), Fe(s), Fe2O3(s), and Fe(g) depending on the temperature and pressure conditions. We attempted to reproduce these temperature and pressure conditions and to extract high-purity Fe by collecting vapor species. FeO compressed powder was heated for 60 seconds in a vacuum using a wavelength of 1080 nm fiber laser at 200 W under a pressure of 10-8 Pa. During heating, the sample surface temperature reached approximately 1700 K. After heating, deposits were found on the quartz glass substrate placed near the sample. We analyzed deposits by powder X-ray diffraction. The XRD patterns of the deposits showed α-Fe peak. However, the chamber pressure could not be measured during heating, as gas generation raised the pressure above the measurement range of the pressure gauge. Next, the chamber pressure prior to heating was reduced to the 10-6 Pa order, the laser output was lowered to 100 W, and the sample was heated for 60 seconds. At this time, the sample surface temperature reached approximately 1500 K, and the pressure increased to the order of 10-2 Pa due to gas generation. Simultaneously, monitoring the gas composition using a quadrupole mass spectrometer revealed an increase in the QMS signal at m/z=56, attributed to Fe, at the start of heating. After heating, deposits were found on the quartz glass substrate placed near the sample and were analyzed by powder X-ray diffraction. The XRD patterns of the deposits showed a weak α-Fe peak.
Consistent with the thermodynamic equilibrium calculations, the experiments indicate that heating to approximately 1500 K on the order 10-2 Pa leads to the generation of Fe-containing vapor. However, gas analysis also detected FeO vapor. In addition, the extracted mass of Fe of the deposits could be quantified because the amount of deposited material was insufficient. In the presentation, we will report the results of measurements conducted under precisely controlled temperature conditions. Moreover, it will focus on the Fe vapor collection system to increase the amount collected.
Acknowledgement: This work was supported by JAXA SSF Program Japan Grant Number JPJXSSF24MX17002.
References: [1] Li, Guangshi, et al. "Lunar in-situ ironmaking through laser-assisted flash vacuum
pyrolysis of iron oxide." Vacuum 230 (2024): 113690.
This study investigated the conditions for extracting iron from FeO without reductants by exploiting the ultra-high-vacuum environment of the lunar surface and conducted iron extraction experiments under vacuum conditions. The temperature conditions for extracting Fe from FeO were calculated across a pressure range of 10-1 Pa to 10-12 Pa by thermodynamic equilibrium calculation. From the calculations, it was found that FeO is in equilibrium in four phases-FeO(s), Fe(s), Fe2O3(s), and Fe(g) depending on the temperature and pressure conditions. We attempted to reproduce these temperature and pressure conditions and to extract high-purity Fe by collecting vapor species. FeO compressed powder was heated for 60 seconds in a vacuum using a wavelength of 1080 nm fiber laser at 200 W under a pressure of 10-8 Pa. During heating, the sample surface temperature reached approximately 1700 K. After heating, deposits were found on the quartz glass substrate placed near the sample. We analyzed deposits by powder X-ray diffraction. The XRD patterns of the deposits showed α-Fe peak. However, the chamber pressure could not be measured during heating, as gas generation raised the pressure above the measurement range of the pressure gauge. Next, the chamber pressure prior to heating was reduced to the 10-6 Pa order, the laser output was lowered to 100 W, and the sample was heated for 60 seconds. At this time, the sample surface temperature reached approximately 1500 K, and the pressure increased to the order of 10-2 Pa due to gas generation. Simultaneously, monitoring the gas composition using a quadrupole mass spectrometer revealed an increase in the QMS signal at m/z=56, attributed to Fe, at the start of heating. After heating, deposits were found on the quartz glass substrate placed near the sample and were analyzed by powder X-ray diffraction. The XRD patterns of the deposits showed a weak α-Fe peak.
Consistent with the thermodynamic equilibrium calculations, the experiments indicate that heating to approximately 1500 K on the order 10-2 Pa leads to the generation of Fe-containing vapor. However, gas analysis also detected FeO vapor. In addition, the extracted mass of Fe of the deposits could be quantified because the amount of deposited material was insufficient. In the presentation, we will report the results of measurements conducted under precisely controlled temperature conditions. Moreover, it will focus on the Fe vapor collection system to increase the amount collected.
Acknowledgement: This work was supported by JAXA SSF Program Japan Grant Number JPJXSSF24MX17002.
References: [1] Li, Guangshi, et al. "Lunar in-situ ironmaking through laser-assisted flash vacuum
pyrolysis of iron oxide." Vacuum 230 (2024): 113690.