Beneficiation and separation process of tungsten-tin symbiotic ores

Tungsten and tin often occur together in the same ore deposits in nature as either symbiotic or associated minerals, making tungsten-tin separation a critical technical challenge in polymetallic ore processing. Due to the similar specific gravity between tungsten minerals (wolframite, scheelite) and cassiterite, effective separation through gravity separation alone is difficult. Therefore, in actual production, processes such as magnetic separation, flotation, electrostatic separation, and combined mineral processing techniques must be selected or combined based on factors like the ore's mineral composition, distribution characteristics, and particle size distribution.

Separation of Cassiterite and Pyrochlore

The primary physical property difference between the two lies in magnetism: pyrochlore exhibits weak magnetism, while cassiterite is essentially non-magnetic. Consequently, magnetic separation is the preferred method for this system. For coarse-grained ore, dry magnetic separators typically achieve thorough separation; For the fine-grained fraction, wet high-gradient magnetic separators are often preferred to minimize dust generation and enhance separation efficiency. Additionally, flotation processes can be employed to separate fine-grained tungsten and tin based on surface property differences.

Separation of Cassiterite and Scheelite

Scheelite and cassiterite exhibit distinct differences in floatability and electrical conductivity. Wolframite generally exhibits good floatability and can be separated from cassiterite through flotation using appropriate collectors and inhibitors. Electrostatic separation is also commonly employed for their separation, but its effectiveness is susceptible to mineral surface contamination (e.g., iron contamination) or compositional complexity, often resulting in incomplete separation. The resulting middlings typically require further processing through other methods to obtain qualified products.

In summary, separating tungsten from tin requires comprehensive consideration of ore characteristics and process applicability. Efficient resource recovery and utilization are achieved through the individual or combined application of magnetic separation, flotation, and electrostatic separation methods.