This research deals with removal of sulphur and extraction of valuable metals such as Cu, Co from Küre calcined pyrites by aqueous (NÜ3 + O2) solution under pressure. Ammonia concentration, oxygen pressure, partide size, solid-to-liquid ratio, total pressure and leach time have been selected as parameîers for the runs. Copper extraction xtent is chosen as primary objective of leaching in ieach processes, and at the end of a series of experiments conducted, the optimal parameter values are found as foll.ows; Ammonia concentration (wt %): 4; oxygen pressure (psig): 57 solid-to-liquıd ratio (g/nıl): 1/4; total pressure (psig): 171, partide size (mm): -1.70; leach time (hour):l.57.72 % of Cu at the end of the experiment conducted with these prameter values is dissolved from the alcined pyrites. Also, 96.47 % of Cu, 20.42 % of Co and 86.65 % of S in the calcined pyrites are dissolved by repeating six times of this experiment. At these conditions, it is concluded that almost complete extraction of especially Cu and S would be possible.