Recovery of copper from PCB leach solution by solvent extraction

Abstract

Discarded computers, mobiles and other consumer electronics (e-waste) are the fastest growing portion of the present day waste stream and are considered hazardous wastes due to the presence of several toxic metals. However such waste can be considered as valuable resource several valuable metals like copper, silver, gold etc. In the present study attempts have been made to recover copper from the leach solution of electronic wastes particularly from PCBs of computers and mobile phones. The metal rich concentrate obtained from the beneficiation circuit is leached in sulphuric acid to dissolve different metals such as copper, zinc, nickel, aluminium, iron etc. The leach liquor obtained contained 23.98 g/l Cu, 0.26 g/l Ni, 0.003 g/l Co, 1.7 g/l Zn, 0.0035 g/l Cd, 0.9 g/l Fe. This solution was further subjected to solvent extraction using LIX 84IC and Acorga M 5640 for the separation and recovery of Cu selectively from the leach solution. Various parameters were studied to optimize the conditions for maximum extraction of copper by both the solvents and their extraction efficiency has been compared. The Mc-Cabe Thiele plot shows the requirement of three stages with O/A ratio of 2:1 for quantitative extraction of copper from the leach liquor at pH 1.7 with 25% LIX 84IC. The counter current simulation studies with O/A ratio of 2:1 up to six stage shows almost complete extraction of copper along without co-extraction of other metals. Finally stripping of copper from the loaded organic phase was performed at different concentration of H2SO4 (2.5–15%, v/v). The stripping efficiency is increased with increasing sulphuric acid concentration.