Abstract:

With the copper/iron cinder as the starting material, ferrous ions were obtained through maturing, acid leaching, reducing and purifying processes, and then iron nanoparticles were prepared by reacting with sodium borohydride in the system of ethanol-water.The nano Fe/SiO₂ core-shell composite particles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and reflectance absorption infrared spectroscopy (RA-IR).The particles were randomly dispersed in paraffin at a mass ratio of 5.5∶4.5 for microwave electromagnetic parameters detection in the frequency range of 2.0—18.0 GHz by vector network analyzer.The results showed that there were two characteristic absorption peaks of Si—O and Si—O—Fe bond appearing at 1389 cm^-1 and 878 cm^-1, which indicated that the nano iron was successfully coated by SiO₂.Through measuring and calculation, the minimal reflection loss was -39.0 dB at 17.2 GHz when the sample thickness was 4.5 mm.So nano Fe/SiO₂ core-shell composite particles can be prepared from copper/iron cider to be used as an effective microwave absorbing material.

Key words:

微波吸收, Fe/SiO₂, 纳米复合材料, 溶胶-凝胶法, 铜铁尾矿制酸烧渣

摘要： 以铜铁尾矿制酸烧渣为原料，经熟化、酸浸、还原和净化等步骤制备亚铁离子；在乙醇-水液相体系中，以NaBH₄作为还原剂，反应生成纳米Fe粒子；最后通过正硅酸四已酯（TEOS）水解包覆制得纳米Fe/SiO₂核壳复合粒子。产物分别采用XRD、TEM、IR等手段进行表征。进一步地，使用矢量网络分析仪在2.0 ~ 18.0 GHz波段内来研究样品的吸波性能。结果表明，IR光谱上在1389 cm^-1和878 cm^-1分别出现对应于四配位Si—O键和Si—O—Fe键的特征吸收峰，说明在Fe粒子表面包覆有SiO₂。通过测试计算得知，当吸波样品厚度为4.5 mm时，其微波吸收性能在17.2 GHz处达到最小值-39.0 dB。由此可见，以铜铁尾矿制酸烧渣为原料，可制得吸波性能优良的纳米Fe/SiO₂核壳复合粒子微波吸收材料。

关键词:

微波吸收, Fe/SiO₂, 纳米复合材料, 溶胶-凝胶法, 铜铁尾矿制酸烧渣