2009 – AusIMM Iron Ore Conference, Perth WA
Beneficiation of magnetite is an integral part of the future of iron ore processing.
Historically, the focus of Western Australian producers has been on exporting Direct
Shipping Ore (DSO) namely hematite. The future for new DSO resources is limited so
companies are changing their emphasis into processing the very large, undeveloped
magnetite ores in Western Australia (WA), using beneficiation to produce shippable
magnetite concentrates. These magnetite resources require higher cost processing
techniques such as fine grinding and beneficiation to produce saleable concentrates.
This distinct difference, from the DSO ores, has lead to the development of a number
of new technologies.
This paper reviews:
- The different techniques used for magnetite beneficiation and provides some case
studies in the WA industry
- The use of Mineral Liberation Analysis (MLA) to describe the nature, grain size,
occurrence and associations of the mineralisation
- The consideration of coarse cobbing as a critical upgrading
- The application of High Pressure Grinding Rolls (HPGR) to save energy
- How the field of magnetic separation has resulted in new machines with higher
field strength (SLon Separators)
- Ultra Fine Grinding requirements of magnetite concentrates
- The application of reverse flotation to reduce silica in the concentrates