Recovery of metals from copper converter slag by leaching with K2Cr2O7-H2SO4

In this study, the effects of some parameters on the extraction of metals from copper converter slag by using a sulphuric acid/potassium dichromate lixiviant were investigated. The leaching kinetic of copper from converter slag was also investigated. The results indicated that increasing the time and temperature have positive effects on the extraction of metals. The best results were obtained by the leaching of converter slag (-200 mesh, 10 g/L of slag/solution ratio) with a lixiviant containing 0.25 M H2SO4 and 0.1 M K2Cr2O7 for 120 minutes at 70 degrees C. Under these conditions, 99.66% Cu extraction yield was achieved. The kinetic evaluations showed that the extraction of Cu from the converter slag is well represented by the shrinking core model controlled by diffusion through the slag matrix. The activation energy of the leach process was calculated as 33.66 kJ/mol for the temperature range of 25 to 70 degrees C (298 to 343 K). Also, reaction order with respect to dichromate was determined as first order in the concentration range of 0.025 to 0.1 M at 25 degrees C (298 K).