Preparation of shape-controlled copper oxide powders from copper-containing solution

Shape-controlled copper oxides have been recovered from copper-containing waste etchant by neutralization with alkali hydroxide. Large amounts of copper-containing waste etchant composed of copper chloride, hydrochloric acid and water are generated from the printed circuit board (PCB) industry. In an environmental and economic point of view, the retrieval of the valuable natural resource from waste is important. In the recycling process of copper oxide from the waste etchant, reaction temperature controls the shapes and sizes of the products. Copper oxide recovered below the reaction temperature of 40 °C was of the needle shape, while copper oxide comes in a platy shape above 40 °C. As a result of the experiments, more than 99% of the copper in the waste etchant was recovered as copper oxide, and its by-products are only sodium chloride and water. Physical properties of the samples have been characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA) and atomic absorption spectroscopy. The particle size scatters in the range of 0.5–10 μm. Shape-controlled copper oxides are expected to be promising precursors for synthesizing copper powder by reduction.