Preparation and mechanism of formation of hematite particles in the Fe-HNO3 system Original Research Article

The mechanism of formation of hematite particles in the Fe-HNO3 system is investigated by introduction of a small amount of PO43− ions to the system. The intermediate species in the reaction, 6-line ferrihydrite, is successfully obtained. The transformation of 6-line ferrihydrite to hematite is investigated. The results show that Fe(II) in the Fe-HNO3 system can catalyze the dissolution of 6-line ferrihydrite, leading to the rapid formation of hematite.