Quantitation of Chloride in Cupric Oxide Recovered from Copper-Containing Etchant Waste

摘要

Copper recycling technologies from copper-containing etchant waste have recently become more attractive. One of the challenges for the copper recycling technologies is the removal of chloride as a contaminant, which influences the plating reaction with recycled copper. Conventional methods for quantifying chloride in cupric oxide still face some challenges with regard to their robustness, sensitivity and simplicity. In this study, a precipitation method using AgCl precipitation titration with aqueous methanol solution was proposed that provides for robust and simple quantitation of chloride in cupric oxide. The titration condition for the proposed method was experimentally optimized, and its sensitivity, linearity and reproducibility were best characterized when the chloride concentration in cupric oxide was in the range of 0.003% to 0.02%. Consequently, 20% methanol was employed to optimize dissolution of CuO while minimizing CUSO_4 precipitation. Under these conditions, the titration method showed good linearity, reproducibility and sensitivity for practical use. The titration method was also compared with the official turbidimetric assay. The comparison showed that the measurements with the titration method was roughly in agreement with the data derived with the official turbidimetric assay.