THE IMPORTANCE OF GRINDING TECHNOLOGY IN THE STRENGTH DEVELOPMENT OF BLASTFURNACE CEMENT CEM III/A

The properties of blastfurnace cement CEM III/A42.5N produced by three grinding technologies, used in three cement plants were examined. These technologie was the following: a) the common grinding of all cement components in the system: high-pressure grinding rolls-two-chambers ball mill. The roller press, with rolls diameters of 170x140 cm, is working in closed circuit with the KHD separator and with the crushed material the two-chambers ball mill of 4.6x14 m dimensions working in open-circuit was feeded. b) separate grinding of slag in one-chamber ball mill 5x15 m, with drying chamber and clinker in two-chambers ball mill 5x14 m, together with setting regulator. Both mills are working in closed circuit with Sepax separators of FLS. The ground cement components are homogenized in one-shaft mixer of IBAU (5). c) common grinding of all cement components in two-chambers ball mill of 4.6x14 m dimensions working in closed circuit with Sepax separator of FLS. It was establish that the particles size distribution of cements are very similar, however, technology a) is assuring the best cement strength, in the 28 days hardening period. It is probably caused by the highest content of the fraction under 10 pm. Simultaneously, as it is commonly known, the technology with roller press and ball mill is assuring the lowest energy consumption.