In the flow technology of manufacturing Portland  cement, operation of grinding the mixture of raw materials is decisive to obtain a certain particle size distribution with a prescribed degree of uniformity  for providing good  clinkerization reaction of the mixture of raw materials.

 Uniformity degree can be considered an important technological parameter which can measure the change of the particles size of the raw materials mixtures during grinding.

This paper presents some correlation between the uniformity degree and a number of granulometric characteristics of some mixtures of raw materials from cement industry which is changing during the grinding.