Pasting characteristics of hematite/quartz systems

Iron ore tailings are currently disposed underwater in tailings dams as slurries containing from 30% to 50% of solids by weight. Conventional or high capacity thickeners are used to recycle most of the process water at the beneficiation plants. The underflow slurry stream of this unit operation feeds tailing basins either by gravity or by pumping. Alternatively, the preparation of pastes from tailings is a very attractive method since it allows their surface disposal without the need of large dam embankments and it also permits co-disposal with mine waste rock in controlled piles. In some specific cases, filling up exhausted open pits by co-disposal of tailings in a paste form and waste rock can be employed with several environmental related advantages. In the present work some physical and rheological characteristics of the slurries and pastes, prepared in different hematite/quartz systems, are presented and compared with some physical, chemical and mineralogical characteristics of the solids.