(pdf) the cement manufacturing process | junaid younis chemical composition of op.c. oxide common name abbreviation approx. amount () cao lime c 6067 sio2 silica s 1725 al2o3 alumina a 38 fe2o3 ironoxide f 0.56 mgo magnesia m 0.14 na2o soda n 0.21.3 k2o potassa k so3 sulfuric anhydride s 13 • cao→limestone • sio2al2o3→clay • fe2o3→impurity in.