MPS vertical roller mills for slag and slag cements 01 11 2007· Operating data The first industrial scale vertical roller mill for slag cement an MPS 3750 C went into operation in Hannover 25 years ago 1 and is still in operation today Figure 3 The capacity of this mill ranges from 60t/h slag with 4100cm²/g to 70t/h CEM III A or 45t/h CEM III B with slag content between 50 80% and fineness of