(1)过滤;Ca(OH)2;
(2)NaAlO2;Fe2O3;CaCO3;Al2O3;
(3)① Al2O3+2NaOH=2NaAlO2+H2O
②Na2CO3+Ca(OH)2=CaCO3↓+ 2NaOH
③2Al(OH)3 Al2O3+3H2O
④2Al2O3 4Al+3O2↑