Mineralogy and technological properties of some kaolin types used in the ceramic industry

Three different kaolin types used in ceramic industry were analyzed by different methods in order to obtain a complete mineralogical and technological characterisation. Studies were carried out by using a combination of analyses (XRD, SEM, methylene blue absorption, particle size distribution) of both the bulk sample, and the fine fraction. The main technological characteristics (drying and firing shrinkage, Pfefferkorn plasticity index, rheology, resistance, and colour after firing) of the ceramic masses prepared by using the analyzed kaolin types were also established. As a result, a direct relationship between the mineralogical composition and particle size distribution of different kaolin types vs. the technological properties of the raw and fired ceramic products was evidenced