Simultaneous determination of trace amounts of copper and cobalt in high concentration zinc solution using UV–vis spectrometry and Adaboost

Abstract

Simultaneous determination of trace ions in zinc metallurgical solution provides effective process information for optimal control in zinc hydrometallurgy. In this paper, Ultraviolet and Visible (UV–vis) spectrometry with the analytical system based on nitroso R salt is applied to simultaneously determine the trace concentrations of copper and cobalt in high and varying concentration zinc sulfate solution. Firstly, fractional differentiation is applied to reduce the overlap between ions and covering of zinc on trace ions. Then, a multi-indexes fusion wavelength selection is utilized to find the optimal combination of variables for the partial least squares model. Next, to reduce the interference caused by competitive reaction and matrix effect of zinc ions, Adaboost creates a group of weak models to analyze trace ion concentration from multiple perspectives. Finally, Adaboost trains the sample weights and model weights of weak models and integrates those weak models into a strong model to predict the trace ion concentration comprehensively. A spectrum dataset containing 72 samples of zinc, copper and cobalt ions mixture solution is prepared for the proposed method. Results show that the proposed method can simultaneously determine the trace concentrations of copper and cobalt in high and varying concentration zinc sulfate solution accurately.