Preparation of ultra fine copper powder from hazardous copper oxide waste

【Objective】 The objective of this study was to purify copper oxide from electronic industrial waste, prepare ultrafine copper powder by hydrogen reduction, and analyze the effects of reduction temperature and reduction time on the micro morphology, particle size and specific surface area of ultrafine copper powder, so as to determine the optimal preparation process conditions.
【Method】 First, copper oxide from electronic industrial waste was purified. Then, the treated copper oxide powder was subjected to high-energy ball milling to obtain a copper oxide powder precursor. Ultrafine copper powder was prepared by hydrogen reduction. The micro morphology of the ultrafine copper powder was observed by scanning electron microscope, and its particle size and specific surface area were detected by laser particle size analyzer. Finally, combined with the experimental data, the effects of reduction temperature and reduction time on the micro morphology, particle size and specific surface area of ultrafine copper powder were analyzed.
【Result】 The experimental results show that the optimal process conditions for preparing ultrafine copper powder are ball milling to an average particle size of 0.18 μm, reduction temperature of 600 ℃, reduction time of 60 min, and hydrogen flow rate of 0.5 L/min. Under these conditions, the average particle size of the obtained copper powder is 8.72 μm, the reduction rate reaches 99.7%, the reduction degree is high, and the powder surface is smooth and not easy to oxidize. The particle size of copper powder increases with the increase of reduction temperature and the extension of reduction time.
【Conclusion】 The purification of copper oxide from electronic industrial waste combined with high-energy ball milling and hydrogen reduction is an effective method to prepare ultrafine copper powder. The optimal process conditions determined in this study can obtain high-quality ultrafine copper powder with high reduction rate, smooth surface and good anti-oxidation performance. The reduction temperature and reduction time are key factors affecting the particle size of ultrafine copper powder, specifically, higher reduction temperature and longer reduction time will lead to larger particle size of copper powder.