An oxidative pressure leaching process to extract silver from the silver-rich residue of demanganized silver-manganese sulfide concentrate with ammonium thiocyanate solution was investigated in this paper. The effects of several factors: temperature, leaching time, oxygen pressure. Fe3+ concentration, lignin concentration, and initial pH of the leaching reagent, on the extraction percentages of silver were studied. The following optimized leaching conditions were obtained: Fe3+ concentration 4.2 g/L, lignin concentration 0.6 g/L, NH4SCN concentration 1.5 M, initial pH value 1.8, and oxygen pressure 1.4 MPa at 120 degrees C for 3 h. Under these optimized conditions, the average extraction percentage of silver was about 88% and 6.5% of NH4SCN was lost after four cycles. The ammonium thiocyanate method has advantages over the conventional cyanidation method and chlorination method, with a higher efficiency, lower toxicity and better selectivity and stability. (C) 2010 Elsevier B.V. All rights reserved.