cement blaine and media coating

You could check the following issues

1) Type of grinding aid being used/change in grinding aid

2) Shell lining profile( if has been worn out there would be less grinding impact hence low blaine and a smooth surface)

3) Not sufficient Grinding media charge( take a crash stop analysis to check the performance of the mill)

4) Clinker hardness( grindability would be difficult hence low blaine)

High temperatures promote coating (Coating is best prevented by keeping the mill cool by 1. mill ventilation 2.water injection 3. cooling the rejects. 240°F is generally considered to be a safe maximum mill discharge temperature of finish mill)

Coating will increase if the mill is ground out (When small material particles are reduced further in size, they have a tendency to “stick” together again, or re-agglomerate)

Coating may be as result of too much moisture as well

Grinding aids combat coating, thus preventing the
re-agglomeration of material