Physical separation of iron ore: magnetic separation

This chapter introduces the principle of how low-grade iron ores are upgraded to high quality iron ore concentrates by magnetic separation. Magnetite is the most magnetic of all the naturally occurring minerals on earth and can be readily extracted by low-intensity magnetic separators from magnetite ores. On the other hand, oxidized iron ores like martite, hematite, specularite, limonite, and siderite are weakly magnetic, and require high-intensity and high gradient magnetic separators to upgrade them. Therefore, it is important to develop and optimize processing flow sheets according to the nature of iron ore to achieve both high recovery and grade at a low cost. Three magnetic separation flow sheets for upgrading magnetite ores and seven flow sheets for oxidized iron ores are discussed.