Cement finish grinding with a MPS roller mill at the San Rafael cement plant in Ecuador

Since the beginning of 2002, Industrias Rocacem S.A has been operating an MPS 4250 BC roller mill at their Latacunga grinding plant in Ecuador. The mill produces pozzolanic cements corresponding to the market requirements in accordance with the Ecuadorian standard INEN 490 and the ASTM standard C595. Clinker pozzolana and gypsum are interground at a mixture ratio of about 69/28/3% to a fineness with a residue of 2.2 to 2.6% on the 45 mum screen. This approximately corresponds to a Blaine value of 4,800 cm(2)/g. The output is 118 tph, which is around 7% higher than the warranted figure. The specific energy requirement of mill, separator and fan is 28 kWh/t, which is approx. 15 % better than the warranted figure. The commissioning was trouble-free and no different from grinding plants for cement raw material, limestone or coal.