LAUSR

Abstract In purification process of zinc hydrometallurgy, excessive amounts of cobalt and copper not only affect production efficiency and product quality, but also waste resources. A spectrophotometric method combining continuous wavelet transform (CWT) with zero-crossing technology is developed to determine cobalt and copper in zinc hydrometallurgy by Ultraviolet-visible (UV–vis) spectroscopy without any separation steps. Firstly, CWT is used for separating overlapping spectra of cobalt and copper by the characteristics of scale decomposition. Then, the precise zero-crossing points of cobalt and copper are obtained by polynomial fitting, which can improve the accuracy of model detection. Finally, the linear regression graphs of cobalt and copper are established by zero-crossing technology. The linear detection range is 0.3–3 mg/L for cobalt and 0.5–5 mg/L for copper. The average relative deviation is 2.71% for cobalt and 3.12% for copper. The RMSEP for cobalt and copper is 0.051 and 0.092, respectively. The outcomes of present study show that the developed method is fast, easy to apply and suitable for detecting and controlling of trace ions of cobalt and copper in purification process of zinc hydrometallurgy.