Air beneficiation uses air as a medium to separate particles of different densities (or sizes). Separation by density is called air beneficiation, and separation by particle size is called air classification.

Air beneficiation is currently mainly used for the separation of some non-metallic ores, such as asbestos and mica from gangue. Air classification is mainly used for dry closed-circuit grinding, fine particle classification before dry beneficiation, and dry dust collection.

Because air has a low medium density, air beneficiation has a relatively low separation efficiency. Suitable feed particle size is generally 1.5~0.005mm; some fibrous or flaky particles can be larger, such as mica, where the maximum particle size can reach 3mm. Moisture content in the material has a significant impact on separation efficiency; the drier the material, the better for separation. Therefore, the production process generates a lot of dust, causing environmental pollution, necessitating a complex dust collection system. However, wind separation has the advantage of not requiring product dehydration, eliminating the very troublesome and costly process of dehydrating and drying fine granular or flaky products. Furthermore, wind separation demonstrates its superiority in severely water-scarce areas.

Commonly used wind separation equipment is shown in Table 4-6.

Table 4-6 Commonly Used Wind Separation Equipment