Abstract
As is well known, impurities contained in raw materials should be minimized for quality cotrol of ferrites. To attain this aim, iron oxide of high purity has been expected to become commercially available.
This paper describes a new method to prepare iron oxide of high purity from waste acid used for steel plate pickling, using a solvent extraction method. Firstly, ferrous ions contained in the acid are oxidized to ferric ions. Then, they are extracted into MIBK solvent. Chemical analysis shows that the extracted ferric solution is highly purified. The solution can be converted to iron oxide of high purity, using the spray roasting method which has been used to prepare iron oxide from the waste acid.
A trially produced iron oxide is found to contain very small amount of impurities, for instance, less than 20 ppm of SiO2.
