In this study we investigated the production of soluble lion and chromium sulfate complexes from high carbon ferrochromium alloy (Fe-Cr-HC) foi utilization as a tanning agent The temperature sulfuric acid concentration and the reaction time between Fe-Cr-NC and sulfuric acid were selected as independent variables for iron and chromium conversion A quadratic response surface model was adjusted using the Box-Behnken statistical experimental design technique The results obtained by solving multi-objective optimization problem have shown about 986-100% Cr and 869-89 1% Fe conversions perchloric acid and ammonium sulfate additions were investigated in older to determine the system limitations The results have showed that an increase of perchloric acid concentration decreased the quantity of soluble chromium and iron compounds while an ammonium sulfate addition improved the conversion of chromium up to 100% (C) 2010 Elsevier B V All rights reserved