Recovery Of Zircon From Sattankulam Deposit In India - Problems And Prospects

Zircon (ZrSiO4) is the most frequently found zirconium ore occurring in heavy mineral sands, from which it is extracted as a co-product in the production of ilmenite and rutile. Estimated world reserves of zircon are 124 million tonnes, highest in Australia (around 56 million tonnes), followed by Mozambique (15 million tonnes), India (12.6 million tonnes) and South Africa (12million tonnes). Zircon finds its application in ceramics (54%) and refractory industries (14%), which account for 68% of zircon?s total world consumption of 1.20 million tonnes. The rest (32%) is consumed in foundry, TV glass, zirconia chemicals and other applications. It is a long recognized feature of the zircon industry that supply is totally dependent upon the concurrent production of titanium minerals. But in recent years, several new developments such as the discovery of zircon-rich mineral sands in Australia, the continuing trend of higher prices of zircon and increase in trade of lower quality zircon have changed the scenario. These factors have prompted more intensive efforts to increase the recovery of zircon, particularly in the process for separating zircon from alumino-silicate minerals. Tata Steel?s proposed heavy mineral sands deposit contains on an average 10% heavy mineral content and 15% slimes of the size below 63 micron. Mineral assemblages of the resource contain65?70% ilmenite, 4?6% rutile, 4% zircon, 16% sillimanite and other minor minerals. Wide size range and tenacious iron oxide coating are the inherent characteristics of this deposit. High concentration of sillimanite among the non-magnetic heavy minerals and heavy surface coatings on the minerals are challenges for high recoveries and production of premium grade zircon. This paper outlines various process steps that were taken at pilot plant stage to produce zircon of premium grade and subsequently develop the appropriate flow-sheet.