Preparation of MgFe₂O₄ microsphere using spray dryer for embolization therapy application

Abstract

MgFe₂O₄ microspheres having a 20–32 µm diameter range were prepared by a spray dryer using bead-milled nano-sized particles. A commercial powder having a several µm particle size was bead-milled to an approximate 6.2 nm crystallite size. The microspheres were obtained using the spray dryer when the air pressure was low (0.03 MPa). The yield of the MgFe₂O₄ 20–32 µm microspheres was improved by combination of a low air pressure and high ferrite concentration in the slurry. The heat generation ability in an AC magnetic field (370 kHz, 1.77 kA/m) was improved by the bead milling.