The U.S. Bureau of Mines investigated caf2-assisted h2so4 leaching to extract mn from domestic silicate manganese resources. A pyroxmangite (mn, fe) sio3) ore containing, in pct, 34 mn, 23 si, 3 ca, and 1 fe was leached at 90 deg c for 3 h in a solution containing, in g/l, 12 mn, 140 h2so4, 130 (nh4)2so4, and 5 caf2. Manganese extraction of 92 pct was achieved. Manganese of greater than 99-pct purity was prepared by electrolyzing the purified pregnant solution at a current density of 50 ma/cm2. The current efficiency was 65 pct.