A Guide to Establishing an Iron Ore Processing Plant

Shanxi-1200TPD-Iron-Processing-Plant

Iron ore, an indispensable "sustenance" for modern industrial civilization, is the core raw material supporting national infrastructure and manufacturing development. This article will systematically elaborate on the nature of iron ore, its diverse beneficiation processes and key equipment, and provide an in-depth analysis of the core considerations for achieving efficient and economical separation. Finally, looking towards the future, we will also explore development trends in intelligence and green transformation within this field, revealing the strategic importance of iron ore processing technology for ensuring resource supply and promoting sustainable development.

1.Core Definition: What is Iron Ore?

Iron ore does not refer to pure iron, but rather to rocks or mineral aggregates found in nature that contain iron elements or iron compounds and have reached economically viable extraction grades.
Simply put, it is the raw material that we can use to smelt pig iron, which is then used to manufacture various steel products. It is the "food" of the steel industry and the most important mineral resource for modern industrial society.

2.Composition of Iron Ore: Ore Minerals and Gangue

An iron ore deposit mainly consists of two parts:

Ore Minerals: These are the valuable minerals containing iron elements. This is the main part we need.

Gangue: These are the rock minerals associated with the ore minerals but have no economic value or cannot be utilized currently, such as quartz and calcite. They need to be separated and discharged as slag during the smelting process.

3.Main Types of Iron Ore

Based on the primary iron-bearing minerals, iron ores are mainly classified into the following types:

(1) Magnetite

• Characteristics: Strongly magnetic, iron-black in color. It is the iron ore with the highest iron content (theoretical iron content 72.4%). It has a dense structure and is hard, usually requiring fine grinding and concentration before smelting.

• Identification: The streak is black; it can be easily attracted by a magnet.

(2) Hematite

• Characteristics: Non-magnetic, dark red or steel-gray in color. It is the most common and primary type of iron ore. The theoretical iron content is 70%, while the actual grade of mined ore is typically between 50% and 65%. It is relatively soft, making it easy to crush and beneficiate.

• Identification: The streak is reddish-brown.

(3) Limonite

• Characteristics: A general term for various hydrous iron oxide ores, ranging in color from yellow-brown, dark brown to black. The iron content is relatively low, usually between 35%-40% and 55%. Due to its loose and porous nature, it consumes more fuel during smelting.

(4) Siderite

• Characteristics: Bluish-gray, yellow-brown in color. The iron content is low (theoretical iron content 48.2%), but after roasting, it decomposes releasing carbon dioxide, resulting in porous, high-grade iron oxide, which is more suitable for smelting.

1.Magnetic Separation

• Principle: Utilizes the strong magnetism of magnetite. In a magnetic field, magnetic minerals are absorbed, while non-magnetic gangue remains, achieving separation.

• Primary Application: The most effective and economical method for processing magnetite.

• Process Flow: Typically follows a "stage grinding - stage magnetic separation" process. This means after the first stage of grinding, primary magnetic separation is used to discard a portion of the tailings. The resulting coarse concentrate then undergoes a second stage of grinding for further size reduction, followed by secondary magnetic separation to improve the concentrate grade and recovery rate.

• Characteristics: Simple process, low cost, low pollution, good separation efficiency.

2.Flotation

• Principle: Utilizes differences in the physical and chemical surface properties (hydrophobicity/hydrophilicity) of minerals. By adding "flotation reagents," the target mineral (or gangue) surface is made hydrophobic. Then, in an aerated and agitated pulp, the hydrophobic minerals attach to air bubbles and float to the surface to form a froth layer, which is skimmed off and collected.

• Primary Application:

Processing finely disseminated, ultra-fine-grained hematite, limonite, siderite, and other weakly magnetic ores (reverse flotation is mainstream).

Purifying magnetic iron concentrates to reduce impurities (such as silicon, phosphorus, sulfur).

• Classification:

Direct Flotation: Floats the iron minerals.

Reverse Flotation: Floats the gangue minerals (e.g., quartz), leaving the iron minerals in the cell. This is currently the more mainstream process due to higher efficiency and lower reagent costs.

• Characteristics: High separation efficiency, especially suitable for complex, finely disseminated ores. However, costs are higher (reagents, energy consumption), and wastewater treatment is a concern.

3.Gravity Separation

• Principle: Utilizes the density difference between iron minerals and gangue minerals. Within a fluid (water or air) medium, and with the aid of gravity, centrifugal force, etc., dense iron minerals are separated from less dense gangue.

• Primary Application: Mainly used for coarse-grained hematite or pre-concentration.

• Characteristics: Lower cost, no pollution, but lower separation efficiency for fine particles. It is often used as a pre-concentration step or in combination with other methods.

1.Crushing Stage

(1) Primary Crushing (First Stage):

• Jaw Crusher:

Function: Acts like "the jaws of a tiger," serving as the first barrier in the crushing line, handling the largest ore lumps.

Characteristics: Simple structure, reliable operation, high capacity, suitable for ores of various hardness.

(2) Secondary and Tertiary Crushing (Second/Third Stage):

• Cone Crusher:

Function: Receives product from the primary crusher for further size reduction.

Characteristics: High efficiency, relatively low energy consumption, large reduction ratio. It is the main equipment for secondary and tertiary crushing. Types include spring cone crushers and hydraulic cone crushers (more advanced, higher automation).

• Impact Crusher:

Function: Uses impact energy to crush ore, can be used for secondary crushing.

Characteristics: Produces product with good particle shape, but generates more fines. Wear parts wear out faster, making it more suitable for medium-hardness, less abrasive ores.

2.Grinding Stage

(1) Ball Mill:

• Function: The most traditional and mainstream grinding equipment. The cylinder contains steel balls; rotation of the cylinder lifts and drops the balls, impacting and grinding the material.

• Characteristics: Stable operation, strong adaptability, can be used for dry or wet grinding (iron ore mostly uses wet grinding). However, energy consumption is high, and efficiency is relatively low.

(2) Semi-Autogenous Grinding (SAG) Mill:

• Function: Combines crushing and grinding functions. The cylinder contains not only steel balls but also uses large ore lumps themselves as grinding media.

• Characteristics: Can simplify the flow sheet (eliminating some secondary/tertiary crushing equipment), but equipment scale and investment are huge. Suitable for large, modern processing plants.

3.Separation Stage

(1) Magnetic Separation Equipment - Primarily for Magnetite

• Magnetic Separator:

Wet Drum Magnetic Separator: Processes pulp, the absolute mainstay for magnetite beneficiation. Classified into concurrent, counter-rotation, and counter-current types based on tank structure.

Dry Magnetic Separator: Processes dry powder material, typically used for pre-concentration discard or in water-scarce areas.

(2) Flotation Equipment - Primarily for Hematite, Limonite, and Purification

• Flotation Machine:

Function: Achieves flotation of hydrophobic minerals by aeration and agitation, causing them to attach to bubbles and float.

Characteristics: The core equipment for the critical reverse flotation process, used to improve concentrate grade and reduce impurities.

(3) Gravity Separation Equipment - Primarily for Coarse Hematite or Pre-concentration

• Spiral Concentrator:

Function: Separates minerals by density using centrifugal force and flowing film action.

Characteristics: No power required, high capacity, low cost, often used for roughing.

• Shaking Table:

Function: Separates mineral particles of different densities both laterally and longitudinally through the asymmetrical reciprocating motion of the deck.

Characteristics: High separation precision, can obtain multiple products. However, capacity is low, and it requires large floor space.

4.Dewatering Stage

(1) Thickener:

• Function: The first stage of dewatering, using the principle of gravity settling to concentrate thin pulp into thick slurry.

• Characteristics: Large diameter (can reach tens of meters) circular tank, high capacity.

(2) Filter:

• Function: Receives the thickened slurry, using vacuum pressure or mechanical pressure to further remove water, forming filter cake.

• Common Types: Disc Vacuum Filter, Ceramic Filter (more energy-efficient, lower product moisture), Plate and Frame Filter Press (for very fine, sticky materials).

1.Test First：Design Later

The ore properties (whether it is magnetite or hematite, particle size distribution, impurity content) must be fully understood to select the correct and economical beneficiation method.

2.Core Principle: "Crush More, Grind Less"

Strive to reduce the ore size as much as possible during the crushing stage to lessen the burden on the most energy-intensive grinding stage. This is key to cost reduction.

3.Strictly Control Separation Conditions

• Magnetic Separation: Focus on magnetic field strength and pulp flow rate.

• Flotation: Precisely control the types and dosage of reagents and the pulp pH. This is critical for success.

4.Pursue High Recovery Rate and High Grade

Strive to maximize the metal recovery rate while ensuring the concentrate grade (quality) meets the required standards. Finding the optimal balance is crucial.

5.Achieve Recycling and Focus on Environmental Protection:

Water: Must achieve internal circulation and reuse, reducing fresh water consumption and wastewater discharge.

Tailings: Tailings (waste residue) must be properly handled to prevent dam failures and pollution, and comprehensive utilization should be sought.

Processing iron ore is a cornerstone of modern industry. Through beneficiation and smelting, raw ore is transformed into steel, providing essential materials for construction, transportation, manufacturing, and many other sectors. It holds strategic importance for national infrastructure and economic security.Looking ahead, the iron ore processing industry is accelerating its shift toward intelligent and green development. By adopting technologies like artificial intelligence and big data, it aims to achieve precise beneficiation, high efficiency, and energy savings. At the same time, green processes such as water recycling and tailings resource utilization are being actively promoted. The goal is to continuously supply the global industrial system with stable, high-quality iron resources at lower energy consumption and environmental cost, thereby supporting a sustainable future.