Leaching performance of imidazolium based ionic liquids in the presence of hydrogen peroxide for recovery of metals from brass waste

Abstract

The application of ionic liquids (ILs), 1-methylimidazolium hydrogen sulfate (HmimHSO(4)), 1-ethyl-3-methylimidazolium hydrogen sulfate (EmimHSO(4)) and 1-butyl-3-methylimidazolium chloride (BmimCl) as leaching agents was investigated in the leaching of copper and zinc from brass waste in the presence of an oxidant, hydrogen peroxide (H2O2). Factors that affect copper and zinc dissolution rates such as ionic liquid concentration, time and temperature were investigated. The results indicated that zinc was dissolved in leach solutions with EmimHSO(4) and HmimHSO(4), completely. Temperature had no considerable influence on copper dissolution rate whilst the rate increased with decreasing IL concentration. In the EmimHSO(4) system, higher copper recoveries were achieved with 40% and 60% IL concentrations compared with IL concentrations of 20% and 80% at 40 degrees C leaching temperature. Copper dissolution rates decreased with EmimHSO(4) concentration at 60 degrees C and 80 degrees C in the following order; 40%> 20%> 60%> 80%. On the other hand the leaching system with BmimCl generally resulted in poor extractions of copper and zinc.