Khan Md Arifur Rahman, Rashed H M M A
Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
Pilot Plant and Process Development Centre, Bangladesh Council of Scientific and Industrial Research, Dhaka, 1205, Bangladesh.
Sci Rep. 2025 Jul 2;15(1):23195. doi: 10.1038/s41598-025-05862-9.
Waste printed circuit boards were collected and shredded by a shredder in the current work. Shredded boards were treated by NaOH solution to remove or loosen up the polymer coating painted on the boards. As copper was the target element in this experiment two step leaching process was adopted. In the first step, low concentration HNO treatment was done to leach the solders and other metals except copper and second step leaching was done by HO added HCl solution for copper leaching. Copper was reclaimed as nanoparticles by electrowinning using this copper-pregnant leach liquor as the electrolyte. Concentration of various elements in the leach liquors of two step leaching process was determined. Different techniques such as particle size analysis, electron microscopy, diffraction and Rietveld refinement were applied to characterize copper nanoparticles. The final copper rich solution found a concentration of copper 29,437.5 ppm with the presence of few other elements. Reclaimed copper particles were approximately 200 to 300 nm revealed by micrographs while having the average crystallite size of 76 nm determined by Rietveld refinement. The presence of metastable cuprous oxide phase was found from the diffraction analysis and the elemental copper phase percentage was 65. Microscopy also confirmed that vacuum drying of the copper particles reduced oxygen contamination from 30 to 6%.
在当前工作中，废弃印刷电路板由一台粉碎机收集并粉碎。粉碎后的电路板用氢氧化钠溶液处理，以去除或疏松涂覆在电路板上的聚合物涂层。由于铜是本实验的目标元素，因此采用了两步浸出工艺。第一步，进行低浓度硝酸处理，以浸出除铜以外的焊料和其他金属；第二步，通过添加过氧化氢的盐酸溶液进行浸出，以浸出铜。使用这种含铜浸出液作为电解液，通过电解沉积将铜回收为纳米颗粒。测定了两步浸出工艺浸出液中各种元素的浓度。应用了不同的技术，如粒度分析、电子显微镜、衍射和Rietveld精修，以表征铜纳米颗粒。最终的富铜溶液中铜的浓度为29437.5 ppm，还含有少量其他元素。显微照片显示回收的铜颗粒约为200至300纳米，而通过Rietveld精修确定的平均微晶尺寸为76纳米。衍射分析发现存在亚稳氧化亚铜相，元素铜相的百分比为65%。显微镜检查还证实，铜颗粒的真空干燥将氧污染从30%降低到了6%。
