Patent ID: 7410537

Claim:
An improved process for the production of Portland slag cement using of granulated blast furnace slag, the said process comprising the steps of: (i) preparing cement clinker (ii) ball-milling of cement clinker for a period ranging between 30-60 minutes under dry condition, (iii) reducing size of granulated blast furnace slag to a size of ranging between 210 to 100 μm, for using as feed for attrition mill, (iv) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes, in an attrition mill with granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding ball ratio in the range of 1:5 to 1:15 to obtain a slurry, (v) removing water from the above said slurry after attrition milling followed by drying to obtain the attrition milled slag, (vi) mixing intimately attrition milled slag obtain in step (v) in the range of: 50 to 95% by weight, ball-milled clinker obtain in step (ii) in the range of: 05 to 45% by weight, and gypsum in the range of: 01 to 05% by weight, for a period in the range of 15 to 30 minutes, to obtain the Portland slag cement.