Individual influence of Na2O and K2O on the properties of Portland cement clinker

In the production of Portland cement clinker the raw mix always contains sodium and potassium oxides, which can accumulate in the calcined material because of their chemical properties, and therefore their amount may increase in the rotary kiln. The Na2O and K2O in the clinker reduce the temperature of C2S occurrence, which can change the microhardness of the clinker minerals and the grindability of the clinker granules. The paper examined the individual effects of Na2O and K2O on the process of C2S formation, microhardness of the silicate phases and the rate of clinker grinding. Earlier C2S formation in the presence of K2O and a higher microhardness of C2S and C3S, obtained at burning the raw mixture with K2O added, than of C2S and C3S, obtained at burning the slurry with Na2O was established. The change in the microhardness of silicate phases reduced the grinding rate of cement by 12.5 %.

Author: D.A. Mishin, A.O. Erygina

Section: Science and production

Keywords: Portland cement clinker minerals, alite, belite, Portland cement clinker, sodium oxide, potassium oxide, grindability, microhardness, compressive strength