Hydrometallurgical Treatment of Waste Printed Circuit Boards: Bromine Leaching
Hao Cui, Corby Anderson
Abstract
This paper demonstrates the recovery of valuable metals from shredded Waste Printed Circuit Boards (WPCBs) by bromine leaching. Effects of sodium bromide concentration, bromine concentration, leaching time and inorganic acids were investigated. The most critical factors are sodium concentration and bromine concentration. It was found that more than 95% of copper, silver, lead, gold and nickel could be dissolved simultaneously under the optimal conditions: 50 g/L solid/liquid ratio, 1.17 M NaBr, 0.77 M Br2, 2 M HCl, 400 RPM agitation speed and 23.5 °C for 10 hours. The study shows that the dissolution of gold from waste printed circuit boards in a Br2-NaBr system is controlled by film diffusion and chemical reaction.
Topics & Concepts
BromineLeaching (pedology)DissolutionCopperSodium bromidePrinted circuit boardNickelBromideChemistryInorganic chemistryMaterials scienceSodiumNuclear chemistryMetallurgyEnvironmental scienceOrganic chemistryOperating systemComputer scienceSoil waterSoil scienceRecycling and Waste Management TechniquesExtraction and Separation Processes