Scheelite mineral and wolframite are the two primary commercial sources of tungsten. Although both minerals are used to produce tungsten concentrates, their beneficiation methods differ significantly because of their mineral properties, occurrence characteristics, and associated gangue minerals.
Selecting the appropriate scheelite mineral beneficiation process is essential for achieving high tungsten recovery, improving concentrate grade, and reducing operating costs. In practice, gravity separation and flotation separation are the two most widely used methods, with the final process determined by the ore's mineralogical characteristics.
Gravity separation is suitable for scheelite mineral with relatively coarse liberation. Since scheelite has a specific gravity of approximately 5.8–6.2 g/cm³, which is significantly higher than most gangue minerals, gravity separation can effectively recover coarse tungsten particles before further treatment.
Common gravity separation equipment includes shaking tables, jigs, spiral chutes, and centrifugal concentrators.
The main advantages of gravity separation include:
Low operating cost
No chemical reagent consumption
High processing capacity
Effective recovery of coarse liberated scheelite mineral
Reduced load on downstream flotation circuits
However, when scheelite mineral is finely disseminated or closely associated with gangue minerals, gravity separation alone is usually insufficient.
The flotation separation process is the most used method for scheelite mineral beneficiation which is generally includes roughing and concentration processes.
Rough separation is to improve the recovery rate of scheelite to the maximum, and the beneficiation process is to obtain qualified tungsten concentrate.
1. Rough separation of scheelite mineral:
The commonly used method is the lime method, which is adding lime to the slurry, they will react with gangue minerals to form precipitates without affecting scheelite and then we got separated scheelite ore.
2. Concentration process of scheelite mineral:
It is mainly to separate scheelite from calcium-bearing gangue minerals. Commonly used processes are heat-process and ambient-temperature flotation processes.
The mineral processing index of the ambient-temperature floatation process is volatile. Normally the scheelite concentrate grade ranges from 55%-60% and contains many impurities. We can recover more than 65% of tungsten concentrate by leaching with hydrochloric acid.
The heating process is to concentrate the product after rough separation to 60%-70%. Then conduct the ambient-temperature flotation process after diluting ore pulp by stirring the slurry that added a large amount of sodium silicate at high temperature.
The ambient-temperature flotation process is become more and more popular because of the advantages of simple processes and ease of operation.
The factors like a low grade, finer dissemination size, and complicated gangue minerals make the flotation process more difficult. The above processes are for reference only. If you want to extract tungsten from the scheelite mineral, please consult a professional company with the qualification of beneficiation, rationally design a customized tungsten ore beneficiation process to obtain the maximum ROI.
There is no single best process. Gravity separation is generally suitable for coarse scheelite mineral, while flotation separation is preferred for fine-grained or complex ores. Laboratory testing is recommended to determine the most appropriate flowsheet.
Yes. A combined gravity separation and flotation separation process is widely used for complex tungsten ores because it improves recovery while maintaining concentrate quality.
Although both are important tungsten minerals, wolframite generally responds better to gravity and magnetic separation, while scheelite mineral is more commonly recovered by gravity separation combined with flotation separation due to its mineral characteristics.
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