R&D and experience of PC Kiln with lowest L/D ratio

The appearances and particle size distribution of GGBS produced by ball mill or vertical roller mill were studied with SEM and laser particle size analyzer. The results showed that the difference of the particle appearance between the products of ball mill and vertical roller mill was not significant. The values of d50 were relative to the specific surface area of GGBS. The particle size distribution of two kinds of products consistent with RRB distribution, the vertical roller mill product had more narrow size distribution, so that it would had more influence on the normal consistency, the fluidity and the setting time. In any age, the flexural strength and compressive strength of the cement mixed with vertical roller products was lower than that of with ball mill products. If the GGBS was used to produce blending cement, keep the s.s.a. as 400m2/kg might be feasible.