Hydrometallurgical Process for Copper Recovery from Waste Printed Circuit Boards (PCBs)

Abstract

Present paper focuses on the selective recovery of copper from the enriched ground printed circuit boards (PCBs) using leaching and solvent extraction. The metal-enriched ground sample obtained from the beneficiation of the sized PCBs in a laboratory scale column type air separator contained mainly 49.3% Cu, 3.83% Fe, 1.51% Ni, 5.45% Sn, 4.71% Pb, and 1.85% Zn. The leaching of the enriched sample with 3.5mol/L nitric acid dissolved 99% copper along with other metals at 323K temperature and 120g/L pulp density in 1h time. The composition of the leach liquor with wash solution was found to be 42.11g/L Cu, 2.12g/L Fe, 4.02g/L Pb, 1.58g/L Zn, and 0.4g/L Ni. The McCabe-Thiele plot indicated the requirements of three counter-current stages for maximum extraction of copper from the leach liquor at pH 1.5 using 30, 40, and 50% (v/v) LIX 984N at the phase ratios (A/O) of 1:3, 1:2, and 1:1.5, respectively. The counter-current simulation studies show the selective extraction of 99.7% copper from the leach liquor feed of 1.5 pH in three stages with 50% LIX 984N at A/O phase ratio of 1:1.5. The stripping of copper from the loaded organic with sulfuric acid produced copper sulfate solution from which copper metal/powder could be recovered by electrolysis/ hydrogen reduction.