3FES+ 12 HNO 3  FE(NO 3 ) 3 + FE 2 (SO 4 ) 3 + 9 NO+ 6 H 2 O

5/ 3FeS+ 12 HNO 3  Fe(NO 3 ) 3 + Fe 2 (SO 4 ) 3 + 9 NO+ 6 H 2 O