Differential comminution of gypsum in cements ground in different mills

Abstract Identical mixes containing fixed amounts of ordinary Portland cement clinker and gypsum were ground in two types of industrial cement mills—viz. ball mill (BM) and vertical roller mill (VRM)—to identical Blaine fineness to examine the effect of any possible differential comminution of gypsum on cement setting times. The present investigation demonstrates that during comminution of cements, the degree of crystallinity of gypsum, as determined by X-ray diffraction (XRD), changes with used grinding mills and this causes changes in setting times of similar cements even when ground to identical Blaine fineness.