Article

The effect of foreign ions on the reactivity of the CaO–SiO 2 –Al 2 O 3 –Fe 2 O 3 system Part II: Cations

Cement and Concrete Research (Impact Factor: 3.85). 10/2001; 32(3):463-469.

ABSTRACT The subject of this paper is the effect of foreign cations on the reactivity of the CaO – SiO 2 – Al 2 O 3 –Fe 2 O 3 system. One reference mixture and eighteen modified mixtures, prepared by mixing the reference sample with 1% w/w of chemical grade MnO 2 , CuO, were studied. The effect on the reactivity is evaluated on the basis of the free lime content in samples sintered at 1200 and 1450 °C. At 1200 °C, the reactivity of the mixture is greatly increased in the presence of Cu and Li oxides. Based on their effect at 1450 °C, the added elements can be divided into three groups. W, Ta, Cu, Ti and Mo show the most positive effect, decreasing the free CaO (fCaO) content by 30 – 60%, compared with the pure sample. Cr and B cause an increase of fCaO content, while the rest of the elements exhibit a marginal positive effect. According to their volatility at 1450 °C, the added compounds can be subdivided into three groups of low (Ti 4 + , Cu 2 + , Mo 6 + , W + 6 , V 5 + , Zn 2 + , Zr 4 +), moderate (Cr 6 + , Co 3 + , Ni 2 + , Mn 4 +) and high volatility (Cd 2 + , Pb 2 +). All burned samples, analyzed by means of X-ray diffraction, have a final mineralogical composition, which corresponds to the structure of a typical clinker. D

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Available from: Konstantinos G. Kolovos, Aug 16, 2015
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    • "The use of alternative raw materials in cement industry that can be used as mineralizers or fluxes, in order to improve the burnability of the raw mix, and the effect of minor components on the formation of the clinker has been broadly discussed and reviewed adequately [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]. Previous relative work from the author has led to the conclusion that certain foreign elements, despite their low concentration , exert a remarkable effect on the sintering process by improving the reactivity of the raw mix and affecting the crystal structure and texture of clinker minerals, and the hydration reactions [17] [18] [19] [20] [21] [22] [23] [24] [25]. It must be noted, however, that when several elements are jointly present in the mixture, the reactivity is not additively changed and any secondary material that is expected to have a positive effect on the reactivity must be individually investigated. "
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