BigPatents India

A process for preparation of monodispersed iron oxide of high coercivity which comprises: i) preparing aqueous solution of iron chloride of concentration in the range of 50 to 150 g/L by dissolving electrolytic iron powder or scrap iron in hydrochloric acid, ii) oxidising the ferrous iron to ferric state by stochiometric amount of nitric acid by known process, iii) purifying the iron solution prepared from scrap iron by solvent extraction using methyl isobutyl ketone or tri-n-butyl phosphate with organic: aqueous (O/A) ratio in the range 2:1 to 4:1, iv) adding ammonium hydroxide solution to iron chloride for precipitating iron or iron hydroxide while stirring with the help of suitable stirrer and maintaining the pH of hydroxide slurry in the range 2.5 to 3.5, v) autoclaving the iron hydroxide slurry in the temperature range of 160 to 200 degree C for 2 hours to precipitate hematite and cooling therafter to 70 degree C, vi) filtering the slurry and washing the precipitate for complete removal of chloride and drying in the temperature range of 50 to 80 degree C for 48 hours.