Characterization of granular materials intervening in cement production

A. M. VIDALES, I. IPPOLITO, O. A. BENEGAS, O. C. NOCERA, F. AGUIRRE AND M. R. BAUDINO

Stuttgart, Germany

Conferencia; Fifth International Conference on the Micromechanics of Granular Media, Powder and Grains 2005; 2005

Raw granular material intervening in cement production consists in limestone grains that present a wide size distribution function, ranging from microns to a couple of inches. Its storage is made in pyramidal piles and, although empirical homogenization techniques are used with good results, there are important factors like segregation and grinding conditions that produce mixtures with different size distribution components that are difficult to control. For that reason, stabilization of a pile will strongly depends on this factors and a study of the influence that different mixing ratios of  particle sizes have in the mixture is important to be explored. In this work, we present experiments to analyze the relationship among characteristic angles of equilibrium for piles and geometry, size and chemical composition of the grains. We also search for correlations among characteristic angles and the relative presence of different sizes of grains that compose the material. We found that chemical composition is correlated with geometry of grains and aspect ratios do not influence critical angles. We also found that critical angles are mainly affected by the ratio of fine grains present in the granular mixture and by the dispersion in size. The obtained results allow us to draw conclusions that might be useful for treatment and piling of  raw material in cement production industry.