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.