Keywords: beach placer, sillimanite recovery, mullite, refractory applications, India, beach sand, thermal treatment, refractory materials, sillimanite alumina powder
Recovery of sillimanite from beach sand of Chhatrapur, Orissa, India and its thermal treatment for refractory application
Beach sands of Chhatrapur, Orissa, India comprise about 18% of heavy minerals, mixed with light minerals like quartz and feldspar. Sillimanite, which has refractory applications, accounts for 8% of these heavy minerals. Sillimanite was separated from garnet, monazite, zircon, rutile, ilmenite, magnetite, hematite and pseudo-rutile by combination of spiral, Wet High-Intensity Magnetic Separation (WHIMS) and flotation techniques. The cleaned sillimanite concentrate was then mixed with pure alumina powder in different proportions and treated in an indigenously developed plasma reactor for preparation of mullite refractory material. Out of the three products obtained, sillimanite alumina powder in the ratio of 75 : 25 was found to have the necessary physical and compositional properties suitable for refractory applications.