India based Grasim Industries Limited filed patent application for process for manufacturing of Portland slag cement. The inventors are Hegde Subray Balachandra and Chelladurai Palaniandy.
Grasim Industries Limited filed the patent application on Aug. 22, 2005. The patent application number is 990/MUM/2005 A.
According to the Controller General of Patents, Designs & Trade Marks, "The present invention concerns a process for manufacturing of Portland Slag Cement, in which blast furnace slag and sodium sulfate are mixed as per predetermined ratio, which is dosed with Cement Clinker as per predetermined ratio and then grinding slag clinker mixture in a ball mill to obtain Portland cement."