CuFeS2 + KMnO4 + H2SO4 Fe2(SO4)3 + CuSO4 + K2SO4 + MnSO4 + H2O

$\mathop{CuFeS_2}\limits^{0}+K\mathop{Mn}\limits^{+7}O_4+H_2SO_4$`->` $\mathop{Fe_2}\limits^{+3}(SO_4)_3+\mathop{Cu}\limits^{+2}SO_4+K_2\mathop{S}\limits^{+6}O_4+\mathop{Mn}\limits^{+2}SO_4+H_2O$

`5xx|`$2\mathop{CuFeS_2}\limits^{0}$`->`$\mathop{Fe_2}\limits^{+3}+2\mathop{Cu}\limits^{+2}+4\mathop{S}\limits^{+6}+34e$

`34xx|`$\mathop{Mn}\limits^{+7}+5e$`->` $\mathop{Mn}\limits^{+2}$

`=>10CuFeS_2+34KMnO_4+56H_2SO_4->5Fe_2(SO_4)_3+10CuSO_4+17K_2SO_4+34MnSO_4+56H_2O`