Grinding mill equipped with classifier is called as close circulation system. Classifier is to separator qualified powder product after grinded it into certain fineness, coarse powder will be send back to mill for re-grinding; it can prevent fine powder cause buffer effect inside the cavity, increases the efficiency, adjust the particle size composition and prevent fine powder from uneven, that is why classifier can ensure grinding quality. The integration performance of classifier not only depends on its efficiency, but also depends on the percentage of 3~30μm particle size from the separated powder. Particles in this interval are the best parts for cement strength. So the efficiency of classifying not only affects the capacity of mill, but also the end product quality.
Too low classifying efficiency will not only curb the mill capacity, but also directly affect the quality of the product.
Too high classifying efficiency will make the mill capacity improved greatly, but has a greater impact on the quality of cement.
What is the best classifying efficiency also is the most favorable for the specific surface area of the cement and the strength requirements? After several experiments and comparison, we believe that the production of cement closed-circuit grinding system powder selection efficiency should be controlled at 60% to 65% or so more appropriate, the maximum should not exceed 70%. 3~3μm particles among Finished production in the proportion will be larger, even over 65%, which will not cause repeat grinding phenomenon due to the low efficiency, and will not reduce the cement strength because of the classifying efficiency is too high.