Process for the removal and recovery of chromium from aqueous industrial effluents

A process for the treatment of aqueous industrial effluents acidified with sulphuric acid containing hexavalent chromium with metal iron in such a way as to reduce the chromium (VI) concentration to below 0.2 mg/l, successive alkalinization of the aqueous effluent so as to permit the precipitation of iron (III) and chromium (III) hydroxides, separation of the solid phase comprising the aforesaid hydroxides from the water which can be recycled or discharged in that it has a chromium (VI) content of less than 0.2 mg/l, thermal treatment of the hydroxides in the presence of air to reoxidize the chromium (III) hydroxide to chromium (VI), dissolution of the chromium (VI) salts in water and separation of the iron (III) hydroxide therefrom, purification of the chromium (VI) salts, recovery of the chromium.