Four Common Iron Ore Beneficiation Methods

Iron ore constitutes the core raw material for the steel industry. While over 300 iron-bearing minerals exist in nature, only approximately 20 are suitable for iron smelting. Magnetite, hematite, limonite, and siderite are the most prevalent. Given the significant variations in properties among different iron ores, tailored beneficiation methods are essential for efficient purification.

Magnetite Beneficiation Methods

Magnetite primarily consists of Fe₃O₄ with an iron content of 72.36% and exhibits strong magnetic properties. For pure, easily beneficiated ore, single weak magnetic separation is employed. Continuous or staged grinding is selected based on grain size distribution. For concentrates with low grade and high impurity content, weak magnetic separation followed by reverse flotation is suitable. For polymetallic or mixed ores, combined processes such as weak magnetic separation followed by flotation are utilised.

Hematite Beneficiation Methods

Hematite consists of Fe₂O₃ with 69.94% iron content and exhibits weak magnetic properties. Gravity separation is employed based on particle size: fine-grained ore undergoes grinding followed by gravity separation; coarse-grained ore is ‘broken but not ground’ with tailings discarded. Fine to ultrafine-grained ore is processed by flotation: single-mineral ores undergo direct flotation, while high-grade gangue with easy flotation properties undergo reverse flotation. When associated with other minerals, combined processes such as weak magnetic - strong magnetic separation are applied.

Limonite Beneficiation Methods

Limonite contains hydrated iron oxide with 50%–65% iron content, exhibiting low hardness, brittleness, and weak magnetism. Coarse-grained ore undergoes washing followed by gravity separation; fine-grained ore employs strong magnetic separation; ultrafine-grained ore requires flotation preceded by desliming. For complex ores with high clay content, combined processes such as gravity separation followed by strong magnetic separation are employed.

Siderite Ore Beneficiation Methods

Siderite consists of FeCO₃ with 48.2% iron content and exhibits weak magnetic properties. Coarse to medium-sized ore is processed via heavy medium or jigging separation; deslimed ore undergoes wet strong magnetic separation for grade improvement; fine-grained ore employs direct or reverse flotation. Alternatively, magnetic roasting followed by weak magnetic separation may be applied.

Iron ore processing requires preliminary beneficiation testing to determine characteristics. The processing flow should be customised based on factors such as mine scale and investment, balancing efficiency and cost.