Efecto del ZnO, ZrO2 y B2O3 en el proceso de clinkerización. Parte I. Reacciones de clinkerizacion y composición de los clínkeres

Abstract

The use of clay-based product waste as an alternative prime material in Portland cement raw mixes raises the ZnO, ZrO2 and B 2O3 content in the clinker. These compounds are found in the enamelled surface of the tile added to the raw mix. The present study explores the effect of adding 0.5 and 2% ZnO, ZrO2 and B 2O3 to the raw mix, separately and jointly, on clinkerization and the distribution and morphology of the mineral phases in the clinker. The findings showed that while ZnO and ZrO2 are fixed in the clinker, B2O3 is partially volatized. Zinc oxide acted as a flux, while neither ZrO2 nor B2O3 increased the molten phase. The addition of the oxides to the raw mix changed the content of the main mineral phases in the clinker. Zinc oxide lowered the C3S and C3A contents, ZrO2 reduced the ferritic phase and B2O3 stabilized C2S. New mineral phases, namely 3CaO · ZnO · 2Al2O3 and CaZrO3, were identified in the clinkers obtained when 2% ZnO and ZrO2 were added to the raw mix.