Sillimanite

Listing ID #912301

We are offering sillimanite. The minerals sillimanite, kyanite and andalusite are all aluminium silicates having the same chemical formula (al2sio5) but different crystal structures and physical properties. They form during metamorphism of alumina-rich sediments. Production worldwide is ~250 000 tyear, mostly andalusite from south africa, the bulk of which is used for manufacture of mullite (al6si2o13) refractories. Conversion to mullite and silica takes place on heating to temperatures in the range 1250–1650°c. Mullite refractories find applications in high-temperature furnaces and kilns.
Small and intermittent production of sillimanite and kyanite has been recorded from the williamstown kaolin deposits, 40 km northeast of adelaide. These represent areas within the orebody that have not been highly altered to kaolin, and are removed during the initial screening process. Selection of ore for sale requires hand sorting of oversized lump from the screening. All product has been sold for refractories manufacture, with production averaging ~70 tyear over the last decade. The deposit is operated by unimin australia ltd.
Other deposits of sillimanite and andalusite have been mined from scree and shallow trenches in the olary district near morialpa and ameroo hill. Kyanite schist near radium hill contains 6–25% kyanite. Highest grade deposits at dey hill have been beneficiated in laboratory tests to give a >98% kyanite concentrate grading 61.7% al2o3.