Granular Component of cement: influence of mixture composition

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

POWDER TECHNOLOGY

Elsevier

Año: 2006 vol. 163 p. 196 - 201

0032-5910

Raw granular materials used in cement manufacturing are limestone grains displaying a broad size distribution, ranging from microns to acouple of inches. They are stored as pyramidal heaps and, although empirical homogenization techniques are used with good results, there areimportant factors like segregation and grinding conditions that produce mixtures with different poorly controlled size. For this reason, the stabilityof the heaps strongly depends on these factors and it is important to study the influence of the respective amounts of particles of different sizes onthe properties of the mixture. In this work, we report experiments analyzing the relationship between the characteristic angles of equilibrium of theheaps and the geometry, size and chemical composition of the grains. We also look for correlations between the values of the characteristic anglesand the relative amounts of grains of different sizes that make up the materials.We demonstrate that the chemical composition is correlated with the geometry of the grains and that their aspect ratio does not influence thecritical angles. We also show that the critical angles mostly depend on the relative amount of fine grains in the granular mixture and on thedispersion of the sizes. The results obtained allow one to draw conclusions that may be relevant to the treatment and storage of raw materials in thecement industry.