Comparison of mesh grinding and chemical washing techniques for the beneficiation of kaolins used in the white cement industry.

Abstract

Kaolins are hydro aluminum silicates which are either monoclinic or triclinic in structure in accordance to their origin. Some common applications of kaolins are paper products, paints, catalyzers, white cement, etc. In the present research four different kaolins which were extracted from Villa de Reyes, S.L.P.; Mexico, were beneficiated using two different techniques: mesh grinding and chemical washing, in order to meet the requirements for the white cement industry, i.e. the mass content of Fe₂O₃ should be less than two percent of the total kaolin mass. XRD, Optical Microscopy, Colorimetry analysis were performed on the four studied kaolins. Mesh grinding and chemical washing techniques showed a similar degree ofbeneficiation. XRD analysis showed six different phases that make up the four different kaolins and are: saponite, kaolinite, wollastonite, stellerite, crystoballite and quartz. Most of Fe₂O₃ was located in the kaolinite, wollastonite and crystoballite phases, as could be corroborated by the combination of XRD, Optical Microscopy and Colorimetry analysis.