J. Phys. IV France 07 (1997) C1-87-C1-88
Optimal Iron Oxides for Obtaining HexaferritesJ. Dufour1, R. Latorre1, C. Negro1, F. López-Mateos1, E.M. Alcalá2 and A. Formoso3
1 Dpto. Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
2 Dpto. Fisica de Materiales, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
3 Dpto. Metalurgia Primaria y Reciclado de Materiales, Centro Nacional de Investigaciones Metalúrgicas, Avda. Gregorio del Arno, n° 8, 28040 Madrid, Spain
Presently, the ferrites industry consumes large amount of iron oxides obtained by spray roasting of steel pickling liquors. The aim of this paper is to propose the synthesis of optimal iron oxides by oxyprecipitation of steel pickling liquors in order to obtain Ba-hexaferrite with high magnetic properties using the ceramic process. As a raw material, it was used sulphuric liquors with iron concentration of 43 g/l. The studied variables for the oxyprecipitation step were temperature, pH, stirring speed, flow of oxidizer to obtain goethite and magnetite. The samples were characterized by XRD and SEM. These oxides were wet milled with barium carbonate and the mixture was calcined in order to obtain Ba-hexaferrite. A VSM was used for determine the magnetic properties and the morphology was studied by XRD and SEM. With these results five iron oxides were selected and the conditions of the ceramic process (calcination temperature and time) for obtaining hexaferrite were optimized versus Hc.
© EDP Sciences 1997