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目的：研究不同等离子体还原介质和还原时间对氧化铜还原的影响。方法采用等离子焰流扫描试样,应用扫描电镜观察还原后试样的表面微观形貌,通过X射线衍射仪分析试样处理前后表面相成分的变化。结果采用N2+热氨为气体介质,其还原产物为Cu4 O3和Cu3 O,相对于其他气体介质得到的还原产物Cu2 O,能将Cu2+还原至更低的价态。还原时间为40 s时,主要还原产物为Cu3 O,其氧含量低于CuO,随着时间延长,亚稳相Cu3 O逐渐转变成较稳定的Cu2 O；当还原时间为100 s时,析出Cu单质。结论 N2+热氨是还原性较强的气体介质。氧化铜中铜离子价态随还原时间增加而降低,同时伴随亚稳定相Cu3 O向Cu2 O转变现象。还原过程中高能电子对CuO颗粒有加热熔融作用,激发态的活性粒子发挥主要的还原作用。

Objective To investigate the influence of different plasma gas and reduction time on the reduction process of CuO. Methods Plasma jet was used to scan the surface of samples. The microstructure after reduction and the change in phase composi-tion before and after reduction were studied by SEM and XRD analysis after the reduction process. Results The reduction products consisted of Cu4 O3 and Cu3 O when using N2+ decomposed NH3 , the valence state of which was lower than that of the reduction product obtained by other gas media, all of which gave the reduction product of Cu2 O. The results showed that the main reduction product consisted of Cu3 O at 40 s, the valence state of which was lower than that of CuO. Metastable phase Cu3 O was gradually transformed into the relatively stable phase Cu2 O as time went by. With extending reduction time, Cu was segregated as the reduc-tion time reached 100 s. Conclusion N2+decomposed NH3 had better reducibility than other gas media. With increasing reduction time, copper ion valence decreased and the Cu3 O phase was transformed from metastable state into a relatively stable state. During the reduction process, the high energy electrons had the heating effect on the CuO particles, and the active particles in the excited state played a major role in the reduction.