High efficiency copper recovery from anode slime with 1-butyl-3-methyl imidazolium chloride by hybrid Taguchi/Box–Behnken optimization method

Abstract

Anode slime which is produced by electrolytic refining of copper, is a significant source of copper production. However, conventional recovery methods for copper are characterized by complex process, huge amount of strong acid consumption and hazardous acid waste. Therefore, novel, green, and high-performance process for copper separation was developed. In this paper, a hydrometallurgical process for copper recovery from copper anode slime was proposed with ionic liquid leaching – precipitation – calcination routes. 1-butly-3-methyl imidazolium chloride (BmimCl) was used as a leaching agent. According to the hybrid Taguchi/Box-Behnken optimization, the optimum leaching conditions for copper leaching were determined as 80 % of ionic liquid concentration, 95 °C of temperature, 4.5 h of time, and 0.07 of solid/liquid ratio. Validation tests performed under optimum leach conditions confirmed the feasibility of the model and 95 % of copper leaching efficiency was obtained. Precipitation with ammonium hydroxide solution at room temperature and calcination at 600 °C processes resulted in a highly pure copper recovery as CuO. Also, under optimum conditions, highly soluble lead was easily separated after filtration by cooling in the form of PbSO4.This hydrometallurgical process is found to be simple, environmentally friendly, and adequate for the recovery of copper from copper anode slime.