Recovery of rare metals from e-waste using mechanical pre-treatment and hydrometallurgical techniques

The disposal of large quantities of electronic scraps generated world wide is causing not only environmental problem but also loss of resources. Therefore, R & D efforts have been made to develop a suitable process for extraction and separation of nitric acid and copper from leach liquor of electronic waste. Nitric acid & copper was recovered using solvent extraction process. Different process parameters viz. pH, aqueous to organic ratio, kinetics of extraction, extraction isotherm to establish stage requirement for extraction in continuous mode etc have been studied to optimize the condition for the separation of nitric acid and metal. The studies showed the selective extraction of nitric acid from leach solution of e-wastes (6.2M nitric acid and 4.7 g/L Cu) followed by selective separation of copper from the acid free solution using Tri-n-Butyl Phosphate (TBP) and 2-hydroxy-5-nonylacetophenoneoxime (LIX 84-IC) respectively. Equilibrium pH 2.0 was found for complete extraction of copper from acid free leach liquor of waste PCBs.