Al → Al2S3 → AlCl3 → Al(OH)3 → Al2O3

2Al + 3S = Al₂S₃.Al₂S₃ + 6HCl = 2AlCl₃ + 3H₂S↑.AlCl₃ + 3KOH = Al(OH)₃↓ + 3KCl.2Al(OH)₃ t° → Al₂O₃ + 3H₂O.

2Al+3S=Al2S3Al2S3+6HCl=3H2S+2AlCl3AlCl3+3NaOH=3NaCl+Al(OH)32Al(OH)3=t=Al2O3+3H2O