8 Al (s) + 3 NaHSO4 (aq) + 3 NaOH (aq) → 4 Al2O3 (s) + 3 Na2S (aq) + 3 H2O (l)
This is an oxidation-reduction (redox) reaction:
3 SVI + 24 e- → 3 S-II (reduction)
8 Al0 - 24 e- → 8 AlIII (oxidation)
NaHSO4 is an oxidizing agent, Al is a reducing agent.