Optimization of sulfuric acid leaching of roasted chalcopyrite concentrate with Box–Wilson experimental design

Chalcopyrite (CuFeS2) is commonly used ore in production of copper, but leaching of this ore is very slow and inefficient due to “passivation” during leaching at atmospheric conditions. In this study, in order to overcome drawbacks of the passivation layers, the concentrate supplied from Eti Bakır A.Ş. Küre Plant in Turkey was roasted at 600 °C for 1 h and after leached. Box–Wilson procedure of statistical experimental design was utilized to identify the effects of significant leaching variables for instance leaching time (X1; 10–120 min), solid/liquid ratio (X2; 0.01–0.20), and H2SO4 concentration (X3; 0.01–1.00 M) on Cu extraction (%) from roasted concentrate and was tried to be optimized. The coefficients of response functions have been calculated by regression analysis, and the estimates have been found to be well in line with the experimental outcomes. The optimal leaching parameters, time, solid/liquid rate and H2SO4 concentration were determined as 115 min, 0.116, and 0.71 M, respectively, and the highest Cu extraction (%) value was calculated as 92.45%.