• 铝热还原NEU-1模拟月壤的热力学及动力学

    Thermodynamics and Kinetics of Aluminothermic Reduction of NEU-1 Lunar Soil Simulant

    • 熔盐电解法可实现月壤原位资源利用中金属与氧气的同步制备,然而月壤自身成分复杂,因此有必要研究脱除月壤中的Si、Fe和Ti等元素的方法。以NEU-1模拟月壤为原料,探究铝热还原模拟月壤的热力学和动力学过程。热分析结果表明,铝热还原模拟月壤的差热曲线出现两个放热峰,对应反应的温度分别为1039 ℃和1258 ℃,表观活化能分别为375 kJ/mol和324 kJ/mol,反应级数分别为2.87和2.85。研究了模拟月壤在高温下的物相演变机制,结果表明1100 ℃以下模拟月壤的物相不发生变化,1200 ℃以上大部分模拟月壤转变为非晶态,而1500 ℃时大部分模拟月壤分解为CaAl2O4、SiO2、Fe2O3和Fe3O4。研究了反应温度对铝热还原模拟月壤产物物相的影响规律,结果表明:1000 ℃以上模拟月壤中的含硅矿物可被铝还原为单质硅,1200 ℃以上模拟月壤中的含铁矿物可被铝还原为Al3FeSi2,1300 ℃以上模拟月壤中的含钙矿物可被铝还原为Al2Ca;升温有利于铝热还原模拟月壤反应的进行,但金属产物与渣相难以分离。

       

      Abstract: The molten salt electrolysis method is suitable for in-situ resource utilization of lunar soil to simultaneously produce metals and oxygen. However, the complex composition of lunar soil leads to intricate electrolyte components, thereby necessitating studies on the thermite reduction of simulated lunar soil for the removal of Si, Fe, and Ti. NEU-1 simulated lunar soil is used as the raw material in this paper to investigate the thermodynamic and kinetic processes of thermite reduction. Thermogravimetric analysis results indicate that the differential thermal curve of thermite-reduced simulated lunar soil exhibits two exothermic peaks at 1039 ℃ and 1258 ℃, with apparent activation energies of 375 kJ/mol and 324 kJ/mol, respectively, and reaction orders of 2.87 and 2.85. The phase evolution mechanism of simulated lunar soil at high temperatures was studied, revealing that the phase of simulated lunar soil remains unchanged below 1100 ℃. Above 1200 ℃, most of the simulated lunar soil transforms into an amorphous state, while at 1500 ℃, most of the simulated lunar soil decomposes into CaAl2O4, SiO2, Fe2O3, and Fe3O4. Finally, the influence of reaction temperature on the phase of thermite-reduced simulated lunar soil products was investigated. The results show that silicon-containing minerals in simulated lunar soil can be reduced to elemental silicon above 1000 ℃. Iron-containing minerals can be reduced to Al3FeSi2 above 1200 ℃, and calcium-containing minerals can be reduced to Al2Ca above 1300 ℃. Increasing temperature facilitates the thermite reduction reaction of simulated lunar soil, but the separation of metal products from slag phases remains challenging.

       

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