High-Efficiency Recovery Technology for Low-Grade White Tungsten Ore

The primary methods for processing white tungsten ore include gravity separation, magnetic separation, chemical beneficiation, and flotation. Flotation can be further divided into ambient-temperature flotation and heated concentration. White tungsten ore generally has a low grade, a diverse mineral composition, and significant variations in grain size distribution. These characteristics make the beneficiation process complex; relying solely on a single, simple method is unlikely to yield satisfactory results. Therefore, combined beneficiation processes that integrate multiple techniques are typically required.

Gravity Separation

Gravity separation is a technique that utilizes the density differences between mineral particles to separate them using specialized equipment. The density of white tungsten ore ranges from 5.8 to 6.2 g/cm³, while that of fluorite is 3.0–3.3 g/cm³ and that of calcite is 2.6–2.8 g/cm³. As can be seen, there is a significant density difference between white tungsten ore and the other two gangue minerals. Effective separation of white tungsten ore from these gangue minerals can be achieved through gravity separation technology. When using gravity separation to isolate scheelite, the target mineral must be liberated as individual particles. Only by meeting this prerequisite can the concentrate product achieve the expected grade. However, due to the fine grain size and brittle crystal structure of wolframite, grinding to a smaller size to achieve single-particle liberation is highly prone to overgrinding and pulverization. In such cases, the effectiveness of gravity separation decreases significantly. Therefore, gravity separation is typically suitable for the separation of coarse- to medium-sized wolframite or for preliminary tailings removal operations.

Magnetic Separation

Magnetic separation is a separation technique that utilizes differences in magnetic properties between mineral particles and is highly dependent on magnetic separation equipment. Since scheelite itself is non-magnetic, the application of magnetic separation in scheelite beneficiation is very limited; it is primarily used to separate associated magnetic minerals, such as wolframite, magnetite, and pyrrhotite. The limitations of the magnetic separation process have driven the development of combined processes with other mineral processing technologies, such as combined magnetic-gravity separation and combined magnetic-flotation processes. These combined processes first use magnetic separation to remove magnetic minerals from the raw ore, followed by subsequent mineral processing of the white tungsten ore, thereby improving processing efficiency and reducing costs.

Chemical Beneficiation

Chemical separation relies on differences in the chemical properties of mineral components. By using chemical methods (such as chemical reagents), the chemical composition of the minerals is altered so that the target component or impurity component selectively dissolves in the leaching reagent, thereby achieving effective separation of the target and impurity components.

In the processing of white tungsten ore, chemical separation processes are suitable not only for high-grade white tungsten ore concentrates and middlings but also for low-grade white tungsten ore. When traditional beneficiation methods cannot effectively extract tungsten from the ore, chemical beneficiation technology can process these ores to produce high-grade white tungsten ore concentrates with high recovery rates. Common chemical beneficiation methods primarily include caustic soda leaching, high-pressure soda leaching, and acid dissolution.

Flotation Process

The flotation process for white tungsten ore primarily involves heated flotation and ambient-temperature flotation, with new reagents and processes continuously being developed. Roughing under ambient-temperature conditions aims to ensure the recovery rate of white tungsten ore, maximizing the recovery of white tungsten resources, while the heated concentration stage focuses on improving the grade of white tungsten concentrate to produce white tungsten concentrate that meets standards.