Al-Al(SO4)3-AlCl3-Al(OH)3-Al2O3
2Al + 3H2SO4 = Al2(SO4)3 + 3H2 Al2(SO4)3 + 3BaCl2 = 2AlCl3 + 3BaSO4 AlCl3 + 3NaOH = Al(OH)3 + 3NaCl 2Al(OH)3 = Al2O3 + 3H2O