Advances in Tungsten Ore Beneficiation Technologies

Introduction

Tungsten, renowned for its high melting point, hardness, and exceptional physicochemical properties, is a strategic material critical to aerospace, machinery manufacturing, and defense industries. With increasing demand, the efficient separation of complex low-grade tungsten ores has become a focal point in the industry. This article systematically reviews technological advancements in tungsten ore beneficiation, emphasizing innovations tailored to diverse ore characteristics.

Characteristics of Tungsten Resources

Tungsten deposits are complex and diverse, primarily comprising scheelite and wolframite-scheelite mixed ores, with the following features:

1.    Low Grade, Fine Dissemination, and Complex Composition: Most ores exhibit fine-grained textures, low tungsten content, and intricate mineral intergrowth, posing significant separation challenges.

2.    Declining Wolframite Resources: Easily processible wolframite reserves are nearly depleted, shifting focus to refractory scheelite and mixed ores.

3.    Associated Tungsten Resources: Approximately 20% of tungsten occurs as by-products in polymetallic deposits, requiring integrated recovery technologies.

Evolution of Beneficiation Technologies

Early tungsten beneficiation relied on single gravity separation. Technological progress has since led to combined processes integrating gravity, flotation, magnetic separation, and hydrometallurgy. Tailored strategies have emerged for different ore types.

Key Beneficiation Technologies

1. Processing of Wolframite-Scheelite Mixed Ores

Innovative approaches for low-grade, fine-grained mixed ores include:

·         High-Intensity Magnetic Separation-Flotation: Pre-concentrate wolframite via pulsating high-gradient magnetic separation, followed by scheelite flotation from magnetic tails. This avoids mutual inhibition in mixed flotation, enhancing overall recovery.

·         Flotation-Magnetic-Flotation Sequential Process: Selective collectors prioritize scheelite flotation, with magnetic separation recovering wolframite from tails, streamlining the circuit.

·         Coarse-Fine Shunt Synchronous Separation: Combining size classification, gravity separation, and slime flotation with advanced centrifuges and reagents addresses uneven grain distribution.

2. Scheelite Concentration Technology

To mitigate interference from calcium-bearing gangue (e.g., fluorite, calcite), the Collector Re-adsorption–Triple Alkali Desorption technique was developed:

·         Pre-adding collectors enhances scheelite surface adsorption;

·         Selective desorption of gangue minerals using sodium silicate, NaOH, and Na₂S suppresses their flotation;

·         Direct concentration eliminates dilution steps, reducing fine particle losses and improving concentrate grade.

3. Tungsten Slime Processing

Novel short-flow processes tackle challenges in fine slime recovery:

·         Cyclone Concentration–Ambient Flotation–Centrifugal Gravity Separation: Pre-concentration reduces slurry volume, while centrifugal units enhance separation efficiency.

·         Desulfurization–Centrifuge–Flotation–Magnetic Separation: Multi-stage processing effectively separates sulfides, wolframite, and scheelite.

4. Utilization of Associated Tungsten Resources

For low-grade tungsten in polymetallic ores, the Magnetic-Flotation Hybrid Process is employed:

·         High-gradient magnetic separation removes weakly magnetic minerals;

·         Flotation enriches scheelite, enabling co-recovery with primary metals.

5. Processing of Isomorphic Molybdenum-Bearing Scheelite

Specialized collectors (e.g., TA-3) and modifier combinations enhance the floatability of scheelite with molybdenum isomorphism, achieving higher grades and recoveries.

Future Innovations

1.    Advanced Reagents: Develop selective collectors and depressants targeting complex mineral surfaces.

2.    Intelligent Equipment: Optimize separation accuracy using high-gradient magnetic separators and centrifugal concentrators.

3.    Streamlined Flowsheets: Reduce intermediate steps to lower energy and water consumption.

Conclusion

Modern tungsten beneficiation has evolved into a multi-process synergy, achieving breakthroughs in mixed ore separation, slime recovery, and by-product utilization. Future advancements integrating mineralogy, surface chemistry, and smart technologies will drive sustainable exploitation of complex tungsten resources.