Dear HongMinh,

There is a test called "Rosin-Rammler" RR; which is a number representing the slope of particle size distribution curve of separator fines (product). Typical range is 1.1 - 1.2

Having high Blaine value along with high 45um residue means you have very fine material along with coarser ones, this results in high range of particle size distribution in one sample i.e. high RR. Which is a matter of high residence time of material in mill and separation efficiency.

This problem is usually encountered when producing limestone-cement or pozzolanic cement. Softer material (limestone) is ground more than harder (clinker).