Recovery of Gold and Copper from Their Mixed Solution by Electrolytic Extraction
摘要
Gold and copper are indispensable metals in the development of modern industry. This work explores a method combining electrolysis and extraction to achieve the simultaneous recovery of gold and copper in a mixed solution. Electrolysis-extraction coupled operation or extraction-electrolysis sequenced operation was conducted in mixed solutions of Au(III)/Cu(II). For the mixed solution system of treating 2 ml of 1000 ppm Au(III), 1000 ppm Cu(II) and 3 ml of 330 ppm Au(III), 1000 ppm Cu(II), we determined the optimal process conditions as follows: the concentration of bis(2-ethylhexyl) phosphate (P204), the extractant for Cu(II), is 20% (v/v), the saponification rate is 10%, and the stripping phase ratio is 1:1. Stainless steel electrodes with an area of 4 cm2 are used for electrolysis at currents of 0.8 mA and 0.3 mA, respectively, for 60 min. Under these conditions, the purity of gold and copper obtained is significantly improved. The removal ratios of the aqueous phase reach up to 97.1% and 99.6% respectively, and the recovery ratios are 95.7% and 93.2% respectively. These results are satisfactory and provide an effective choice for the recovery of gold/copper in mixed solutions, such as in the metal chloride leaching process.