CuFeS2-II + 20 HNVO3 Fe(NVO3)2 + Cu(NVO3)2 + 2 H2SVIO4 + 16 NIVO2 + 8 H2O

This is an oxidation-reduction (redox) reaction:

2 S-II - 16 e- 2 SVI (oxidation)

16 NV + 16 e- 16 NIV (reduction)

Change the oxidation states