Metallurgical performance evaluation of space-weathered Chang’e-5 lunar soil

Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in situ.However,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the Earth.In this study,scanning electron microscopy and transmission electron microscopy analyses were performed on Chang’e-5 powder lunar soil samples.The microstructural characteristics of the lunar soil may drastically change its metallurgical performance.The main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral crystals.The nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar soil.Hydrogen ions injected by solar wind may promote the hydrogen reduction process.The widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar soil.Therefore,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar soil.This is a property that earth samples and tradi-tional simulated lunar soil lack.The application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.

A novel strategy to extract lunar mare KREEP-rich metal resources using a silicon collector

The lunar mare potassium(K)-,rare-earth elements(REEs)-and phosphorous(P)-rich(KREEP-rich) region is a unique late-stage product of magma crystallization,in which ilmenite and incompatible elements have high grades,thus forming a giant natural reservoir.The extraction and purification of the high-value metal resources in the KREEP-rich region not only meet the construction needs of the lunar base but also solve the problem of resource scarcity on Earth.In this study,photovoltaic elemental silicon(Si) was used as a collector to extract ilmenite resources,REEs,and nuclear energy elements from basalt in the lunar mare KREEP-rich region at 1873 K.Based on experimentation,the metals titanium(Ti)and iron(Fe) in the lunar mare ilmenite are found to be enriched and solidified in the form of Si-based alloys.The contents of valuable incompatible elements in the KREEP-rich area are also found to be enriched and contained in the incompatible trace elements(ITEs) phase of the alloy.Among them,REEs(e.g.,cerium(Ce) and thulium(Tm)) and nuclear elements(e.g.,thorium(Th) and uranium(U)) are found to account for 82.61 wt% of the ITEs phase.This process provides a simple and feasible scheme for the insitu resource utilization(ISRU) of the lunar surface and is suitable for the extraction and enrichment of lunar metal resources.

电场对CaO-SiO2-Al2O3熔渣的结构调控

针对硅中硼难去除的问题,从熔渣结构层面进行研究,通过观察熔渣不同部位在不同电场条件下熔渣结构的变化,分析不同电场条件下高温骤冷所得熔渣结构变化,探索引入电场对熔渣结构影响。结果表明,引入电场会引起熔渣中离子定向移动与重新分配,改变熔渣结构。熔渣上部结构在电场作用下解聚更彻底,远离渣金界面处熔渣结构变化较小。电场增强有利于熔渣解聚,电场强度达10V时,熔渣中结构单元会转变为聚合度更低的Q0结构单元。熔渣上部结构对电场变化更敏感,电场改变,熔渣下部结构变化较小。