The present work is directed to the production of pure aluminium oxide (Al2O3) known as alumina from the solid waste cake produced as a by - product from aluminium small factories using many of easy and economic methods. alumina of ?- or ?- form is produced respectively. The produced alumina can be used in different applications such as sorption and separation of Cr(III) Cr(VI) from their mixture and Fe(III) from commercial phosphoric acid.