\(Ba\left(OH\right)_2+2HCl\rightarrow BaCl_2+2H_2O\\3 BaCl_2+Al_2\left(SO_4\right)_3\rightarrow3BaSO_4+2AlCl_3\\ AlCl_3+3NaOH\rightarrow Al\left(OH\right)_3+3NaCl\\ 2Al\left(OH\right)_3-^{t^o}\rightarrow Al_2O_3+3H_2O\\ 2Al_2O_3-^{đpnc,criolit}\rightarrow4Al+3O_2\)