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 objective was to optimize the leaching conditions for maximum recovery of copper and understand the kinetic behavior of the process. The methodology involved conducting experiments to determine the effects of time, temperature, and chemical concentrations on metal extraction rates. Specifically, the leaching of converter slag with a lixiviant containing 0.25 M H2SO4 and 0.1 M K2Cr2O7 was assessed at varying conditions. The results indicated that increasing the time and temperature had significant positive effects on metal extraction, achieving a maximum copper extraction yield of 99.66% under optimal conditions of a 10 g/L slag/solution ratio for 120 minutes at 70 °C. Kinetic evaluations suggested that the leaching process followed the shrinking core model, indicating diffusion control through the slag matrix, with an activation energy of 33.66 kJ/mol. The reaction order concerning dichromate concentration was established as first order within a range of 0.025 to 0.1 M at 25 °C. These findings provide insights into effective methods for recycling valuable metals from industrial waste.