\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(Al_2\left(SO_4\right)_3+6NaOH\rightarrow2Al\left(OH\right)_3+3Na_2SO_4\)
\(2Al\left(OH\right)_3+Ba\left(OH\right)_2\rightarrow Ba\left[Al\left(OH\right)_4\right]_2\)
\(Ba\left[Al\left(OH\right)_4\right]_2+H_2SO_4\rightarrow2Al\left(OH\right)_3+BaSO_4+2H_2O\)
\(2Al\left(OH\right)_3\rightarrow Al_2O_3+3H_2O\)
\(2Al_2O_3\rightarrow4Al+3O_2\)