The function of the lime selection classifier is to separate and collect qualified product from unqualified coarse powder according to the requirements of product fineness or specific surface area, by returning the unqualified coarse powder to the ball mill for re-grinding. Its overall working principle involves the use of gas-powder mixing to form a gas-solid two-phase flow, causing the dust-containing gas flow to rotate, giving coarse powder particles a greater inertial centrifugal force, and also a higher radial separation velocity. This enables the separation of coarse and fine powders, while also employing appropriate methods for the separate collection of coarse and fine powders.

The working principle of the limestone classifier is mainly achieved through three functions: spreading material, grading, and finished product collection. However, the specific working processes for these three functions vary among different types of classifiers.

The centrifugal classifier employs bottom-spraying to separate and collect coarse and fine powders through the circulation of air and powder within the machine. Its feature is that, as the air and powder circulate internally within the machine, this classifier is termed an internal circulation type.

The Cyclone Separator also employs bottom feeding, but the air intake is via a tangential bottom entry. As the air enters and rises, it passes through the feeding curtain, then is separated by the rotating blades or conical rotating drum. The air stream separated by this process carries the finished fine powder out of the separator chamber. The dust-laden air discharged from the separator chamber is then sent to the cyclone separator for gas-powder separation to collect the finished product.

Its feature is that, as the clean airflow exiting the cyclone enters the fan for recirculation, this type of classifier is referred to as an external circulation operation.

The O-Sepa series of separators utilize an upper feeding method, where the material is not propelled by an inertia centrifugal force from a feeding disk to form a material curtain, but rather falls freely due to the material's own weight after being distributed by the feeding disk, creating a material veil. The flat tangential airflow is then channeled through a cylindrical drum to form a cylindrical vortex for separation. The finished fine powder is carried out of the separator with the air stream and collected in a dust collector.

Its features include: Due to the use of a cylindrical drum in this type of classifier, it can form a relatively uniform vortex field, resulting in good separation effects and high selection efficiency. Additionally, the air flow from the deduster is directly exhausted through the fan without recirculation.