Beneficiation of Ilmenite: Methods, Equipment and Processes

Ilmenite beneficiation represents a cornerstone of modern titanium production, serving as the critical first step in extracting valuable titanium dioxide from naturally occurring mineral deposits. As global demand for titanium-based products continues to rise across industries ranging from aerospace to pigments, the efficiency of ilmenite processing has become increasingly significant. This article examines the four major beneficiation methods—gravity separation, magnetic separation, electrostatic separation, and flotation—that form the foundation of contemporary ilmenite processing. Additionally, we explore the specialized equipment that enables these separation techniques and analyze the optimized process flows that maximize recovery rates while minimizing operational costs. Understanding these elements is essential for industry professionals seeking to enhance productivity, improve concentrate grades, and adapt to varying ore characteristics in an increasingly competitive global market.

 

Four Major Methods of Ilmenite Beneficiation

Ilmenite (FeTiO₃) is one of the most important titanium-bearing minerals used in the production of titanium dioxide pigment and titanium metal. The beneficiation of ilmenite involves several specialized methods designed to separate it from gangue minerals and increase the titanium content. Below are the four major methods used in ilmenite beneficiation.

1. Gravity Separation

Gravity separation exploits the density difference between ilmenite (specific gravity 4.5-5.0) and gangue minerals.

Key Technologies

• Spiral Concentrators: Most widely used for initial concentration of ilmenite
• Shaking Tables: Used for finer particle treatment and final cleaning
• Jigs: Effective for processing coarser ilmenite particles
• Centrifugal Concentrators: Used for fine particle recovery (Knelson or Falcon concentrators)

Application Scenarios

• The primary processing step for beach sand deposits
• Treatment of weathered ilmenite ores
• Processing of alluvial deposits
• Pre-concentration before magnetic or electrostatic separation

Advantages:

• Low operating costs
• Environmentally friendly (minimal chemicals)
• High throughput capacity
• Effective for coarse to medium-sized particles

 

 

2. Magnetic Separation

This method utilizes the paramagnetic properties of ilmenite to separate it from non-magnetic minerals.

Key Technologies

• Low-Intensity Magnetic Separation (LIMS): Removes strongly magnetic minerals like magnetite
• High-Intensity Magnetic Separation (HIMS): Separates ilmenite from non-magnetic minerals
• Wet Magnetic Separators: Used for finer material processing
• Dry Magnetic Separators: Better suited for coarser fractions

Application Scenarios

• Processing of mixed heavy mineral concentrates
• Separation of ilmenite from rutile, zircon, and silicates
• Purification after gravity concentration
• Treatment of weakly magnetic ilmenite varieties

Advantages

• High selectivity for ilmenite
• Effective across various particle sizes
• Can be operated in both wet and dry conditions
• Suitable for automated continuous operation

 

3. Electrostatic Separation

Electrostatic separation differentiates minerals based on their electrical conductivity differences.

Key Technologies

• High-Tension Roll Separators: Most common for ilmenite/rutile separation
• Electrostatic Plate Separators: For finer fractions
• Corona Discharge Separators: Creates charging differences between conductive and non-conductive minerals

Application Scenarios

• Separation of ilmenite (conductive) from non-conductive minerals like zircon
• Final cleaning stage after magnetic separation
• Processing of dry, fine-grained beach sand deposits
• Production of high-grade concentrates

Advantages

• Excellent separation efficiency for certain mineral pairs
• Produces high-grade concentrates
• No chemical additives required
• Effective for fine particles when properly controlled

 

4. Flotation

Flotation uses surface chemistry properties to selectively separate ilmenite from other minerals.

Key Technologies

• Conventional Mechanical Flotation Cells: Standard approach for bulk processing
• Column Flotation: Higher selectivity for fine particles
• Collector Reagents: Fatty acids, hydroxamates, and sulfonates
• pH Modifiers: To optimize collector performance

Application Scenarios

• Processing complex ore bodies where physical methods are insufficient
• Treatment of fine-grained ilmenite where gravity methods are ineffective
• Separation of ilmenite from silicates and other titanium minerals
• Beneficiation of weathered or altered ilmenite deposits

Advantages

• Highly selective when properly optimized
• Can process very fine material
• Adaptable to varying ore compositions
• Can achieve high recovery rates

 

Integrated Processing Flowsheets

Most commercial ilmenite beneficiation operations employ combinations of these methods in integrated circuits:

Beach Sand Processing:

Raw Sand → Spiral Concentration → Magnetic Separation → Electrostatic Separation → High-Grade Ilmenite

Hard Rock Ilmenite Processing:

Crushing/Grinding → Gravity Concentration → Magnetic Separation → Flotation → Ilmenite Concentrate

Weathered Ore Processing:

Scrubbing → Desliming → Spiral Concentration → Magnetic Enhancement → Final Cleaning

 

Each beneficiation method has its specific advantages and limitations, and the selection depends on the ore characteristics, desired product quality, available infrastructure, and economic considerations. Modern ilmenite processing plants often combine multiple techniques to maximize recovery and grade.

 

 

Ilmenite Beneficiation Equipment

Ilmenite in primary ore usually coexists with magnetite and is distributed in magnetite particles or cracks. To obtain pure titanium ore, the beneficiation process is needed to improve the grade of the ore.

The beneficiation process of ilmenite is relatively complicated, involving multiple beneficiation methods such as gravity separation, magnetic separation, flotation, and electrostatic separation, so more beneficiation equipment is needed. Including concentrators that classify ore particles according to particle size, gravity separation equipment for selecting tailings, weak magnetic separators for removing strong magnetic minerals, strong magnetic separators for selecting ilmenite, flotation machines for flotation of sulfides and fine-grained ilmenite, and electrostatic separators for selecting ilmenite.

 

Main Process Flow of Ilmenite Beneficiation

 

The beneficiation process of ilmenite should be designed according to the properties of ilmenite. There are two common beneficiation process flows, “gravity separation – strong magnetic separation – flotation” or “gravity separation – strong magnetic separation – electrostatic separation (desulfurization before separation)”.

At the beginning of the process, the ore particles are first classified by a thickener to distinguish coarse-grained ore from fine-grained ore.

The coarse-grained ore is classified into fine-grained ore and tailings by gravity separation. Gravity separation has a low cost and little environmental pollution. Most of the useless gangue and soil can be removed by spiral chutes, shaking tables, and other equipment to obtain enriched concentrates.

The fine-grained ore from gravity separation enters the magnetic separation stage. Ilmenite is a weakly magnetic mineral. Under a strong magnetic field, ilmenite and gangue minerals are separated. Ilmenite, which is difficult to enrich by gravity separation, is enriched in this process, so magnetic separation is common in the selection and tailings stages.

The remaining material after the magnetic separation of the titanium concentrate is not useless. After flotation, sulfur concentrate can be obtained. Fatty acids, oleic acid, and its salts are commonly used as flotation collectors for ilmenite. After years of practice, researchers have found that the combination of multiple agents is better than the use of a single agent, so in recent years, they have been exploring the synergistic effect of agents.

The coarse-grained ore after gravity separation needs to be separated by electrostatic separation to separate the titanium concentrate, especially when it contains not only ilmenite and rutile but also non-conductive minerals such as quartz. Electrostatic separation can be used as the last step in the production of titanium concentrate.

 

Conclusion

The beneficiation of ilmenite remains both a science and an art, requiring careful consideration of ore mineralogy, particle characteristics, and desired product specifications. As we have explored, the four primary methods—gravity, magnetic, electrostatic, and flotation separation—each offer distinct advantages when applied to appropriate ore bodies and integrated into well-designed processing circuits. The selection and optimization of equipment, from spiral concentrators to high-intensity magnetic separators, directly impact operational efficiency and economic outcomes. Looking forward, technological innovations continue to enhance traditional beneficiation techniques, with advancements in sensor-based sorting, energy-efficient grinding, and intelligent control systems presenting new opportunities for process improvement. For mining operations seeking to remain competitive in the titanium value chain, adopting tailored beneficiation strategies that combine these methods and technologies in response to specific ore characteristics will be crucial. Ultimately, successful ilmenite beneficiation depends not merely on equipment and methods, but on the skillful integration of these elements into coherent, adaptable processing systems designed for specific deposit characteristics.