A succinct process for recovering Cu from acidic waste etchant (AWE) was developed in this work, which included recycling Cu via oxalate precipitation, preparing CuO nanoparticles by thermal decomposing the precipitate, and recovering NaCl via evaporation crystallization. A comparison of copper precipitation by H₂C₂O₄ and Na₂C₂O₄ suggested that an efficient recovery efficiency of Cu was obtained by Na₂C₂O₄ (∼99%), which was higher than that by H₂C₂O₄ (80.31%). Through thermodynamic analysis, a H⁺-release mechanism was proposed to explain the significant difference in copper precipitation between Na₂C₂O₄ and H₂C₂O₄. By parameter optimization, 99.8% of Cu was recovered without adjusting pH value under optimal conditions, such as temperature of 40 °C, sodium oxalate of 1.2 mol/mol, and reaction time of 2 h. Furthermore, CuO nanoparticles with a purity of 99.92% and particle size of 30 nm were prepared, and the phase transformation of Cu was investigated in-depth using X-ray diffraction (XRD), Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrum (FT-IR). Finally, the chloride ions were recovered as NaCl at 99.51% purity. This study provides a potential route to deal with strongly acidic waste etchant and achieve its high-value utilization.

本工作开发了一种从酸性废蚀刻剂 (AWE) 中回收铜的简洁工艺，包括通过草酸盐沉淀回收铜、通过热分解沉淀物制备 CuO 纳米颗粒以及通过蒸发结晶回收 NaCl。比较 H₂C₂O₄和 Na₂C₂O₄₂C₂O₄对铜的回收效率较高（~99%），高于 H₂C₂O₄(80.31%)。通过热力学分析，H^提出了+释放机制来解释Na ₂ C ₂ O ₄和H ₂ C ₂ O _{4之间铜沉淀的显着差异}。通过参数优化，在温度为40 ℃、草酸钠为1.2 mol/mol、反应时间为2 h等最佳条件下，无需调整pH值即可回收99.8%的Cu。此外，制备了纯度为99.92%、粒径为30 nm的CuO纳米颗粒，并利用X射线衍射（XRD）、扫描电子显微镜（SEM）、X射线光电子等手段对Cu的相变进行了深入研究。光谱学 (XPS) 和傅里叶变换红外光谱（FT-IR）。最后，氯离子以 99.51% 的纯度作为 NaCl 回收。该研究为处理强酸性废蚀刻剂并实现其高价值利用提供了一条潜在途径。