Mullite–Cobalt (II, III) Oxide System: Preparation of Ceramic Pigment Using Recycling of Fly Ash

The present work depends on recycling of fly ash by preparation of stoichiometric mullite containing various amounts of Co₃O₄; 0, 5, 10, 15 wt.% to obtain pigment ceramic materials. The mixtures were sintered at different temperatures; 1250, 1350, 1400, 1450, 1500 and 1550 ^∘C to follow the phase compositions, structure, physical, mechanical, electrical, magnetic properties and the color behaviors. The results indicate that the sintering at 1250 ^∘C is the optimum condition for the formation of the blue pigment ceramic materials. The sintering from 1250 to 1500 ^∘C shows increase in the bulk density and the strength properties up to 15 wt.% Co₃O₄. The incorporation of cobalt (II, III) oxide into the mullite system enhances the electrical and magnetic properties to be used as ferromagnetic materials.