Evaluation of Acid Leaching of Low Grade Chalcopyrite Using Ozone by Statistical Analysis

Several attempts have been made to optimize the process and reduce operating costs of the acid leaching of low grade sulphide copper ores. In this study, we conducted acidic leaching of low-grade chalcopyrite by using ferric ion and ozone as oxidants, at 25 degrees C. In particular, we used a Taguchi L9 experimental design (four factors, three levels) to determine the effects of particle size, ferric ion and sulphuric acid concentrations ([Fe+3] and [H2SO4]) and ozone (O-3) mass flow rate, on the amount of copper extracted. Statistical analysis showed that [Fe+3] had the greatest effect on the amount of copper extracted followed by particle size and O-3 mass flow rate. [H2SO4] had no statistical significance. The highest copper leaching yield was obtained for [Fe+3]= 0.5 M, O-3 flow rate = 0.5 g,/h, [H2SO4]=0.1 M and particle size=398 mu m.