How to Process Iron Ore?

Iron ore processing plant in South Africa

Iron ore is the fundamental raw material for the iron and steel industry and is crucial for economic development. Processing iron ore scientifically and efficiently directly impacts resource utilization rates and production efficiency. This article provides an overview of iron ore processing techniques, key stages, and development directions, offering a reference for related production and applications.

Iron ore refers to iron-bearing mineral assemblages (rocks/sediments) from which metallic iron can be economically extracted. It is the core raw material for the iron and steel industry. Colloquially, the term may also refer to the mine from which the ore is extracted.

1. Main Types and Composition of Iron Ore

（1）Magnetite (Fe₃O₄)

• Strongly magnetic, theoretical iron content of 72.4%, easy to beneficiate.

（2）Hematite (Fe₂O₃)

• Cherry-red streak, theoretical iron content of 70%, very widely distributed.

（3）Limonite (mFe₂O₃·nH₂O)

• A mixture of hydrous iron oxides, typically with a lower iron grade.

（4）Siderite (FeCO₃)

• A carbonate mineral, requires roasting for decarbonization before smelting.

1. Magnetic Separation

（1）Application

• Magnetite (strongly magnetic).

（2）Principle

• Utilizes differences in magnetic susceptibility to separate iron minerals from gangue in a magnetic field.

（3）Characteristics

• Low cost, simple process, stable performance. It is the primary process in the vast majority of magnetite processing plants.

2. Low-Intensity Magnetic Separation – High-Intensity Magnetic Separation

（1）Application

• Mixed ores containing magnetite and hematite/limonite.

（2）Flowsheet

• Low-intensity magnetic separation is applied first to recover magnetite, followed by high-intensity magnetic separation to recover weakly magnetic iron minerals.

（3）Characteristics

• Strong adaptability; commonly used for processing complex ores.

3. High-Intensity Magnetic Separation

（1）Application

• Weakly magnetic iron ores such as hematite, limonite, and siderite.

（2）Principle

• Uses high magnetic field strength to capture weakly magnetic iron minerals.

（3）Characteristics

• Environmentally friendly and relatively low cost as it does not require large quantities of reagents.

4. Flotation

（1）Application

• Hematite, specularite, finely disseminated, and refractory iron ores.

（2）Main Flotation Method

• Reverse flotation

（3）Characteristics

• Capable of producing high-grade iron concentrate, making it the mainstream process for producing premium fine concentrates.

1. Crushing and Screening

• Jaw Crusher

• Cone Crusher

• Vibrating Screen

2. Grinding and Classification

• Ball Mill

• Rod Mill

• Spiral Classifier

• Hydrocyclone

3. Separation Equipment

• Low-Intensity Magnetic Separator

• High-Intensity Magnetic Separator

• Flotation Machine

• Magnetic Separation Column / Cleaning Magnetic Separator

4. Dewatering Equipment

• Thickener

• Disk Vacuum Filter/ Ceramic Vacuum Filter

• Filter Press

5. Auxiliary Equipment

• Belt Feeder

• Feeder

• Agitation Tank

The processing of iron ore primarily involves a series of stages including crushing, screening, and grinding the raw ore. These processes reduce large run-of-mine rocks to a particle size suitable for subsequent smelting, providing qualified feedstock for the iron and steel industry. The future direction of development lies in automation, enhanced energy efficiency, and environmentally friendly practices to further improve production efficiency and resource utilization levels.