• copper flotation waste;
  • immobilization;
  • fly ash;
  • metal leachability;
  • adsorption kinetics


Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study was to perform a laboratory investigation to assess the feasibility of immobilizing the heavy metals in copper flotation waste. For this purpose, samples of copper flotation waste were immobilized with fly ash (FA). In this study, the leaching characteristics of copper flotation waste have been evaluated by the Toxicity Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP), Extraction Procedure (EP Tox), and Field Leach Test (FLT) tests methods. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudosecond order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudosecond order kinetic model was the best fit kinetic model for the experimental data. The results show that adding FA to the copper flotation waste drastically reduces the heavy metal content in the leachate. © 2011 American Institute of Chemical Engineers Environ Prog, 2011