2 KMnO4 + 3 Mn(SO4) + 2 H2O → 5 MnO2 + K2SO4 + 2 H2SO4
This is an oxidation-reduction (redox) reaction:
3 MnII - 6 e- → 3 MnIV (oxidation)
2 MnVII + 6 e- → 2 MnIV (reduction)
Mn(SO4) is a reducing agent, KMnO4 is an oxidizing agent (synproportionation (comproportionation)).