Copper is the most noble of first row transition metals and occurs in small deposits in serveral countries. Ores of copper include chalcanthite `(CuSO_(4).5H_(2)O)`, atacanite `[Cu_(2)Cl(OH)_(3)]`, cuprite `(Cu_(2)O)`, copper glance `(Cu_(2)S)`, and malachite `[Cu_(2)(OH)_(2)CO_(3)]`. However, `80 %` of the world copper production comes from the ore chalcopyrite `(CuFeS_(2))`. The extraction of copper from chalcopyrite involves partial roasting, removal of iron and self-reduction.
In self-reduction, the reducing species is.