Estimation of the drying behaviour for different clay raw materials - drying sensitivity techniques review Epitoanyang 2022

Abstract

In order to rate the drying behavior of different clay raw materials it is necessary to establish the criteria for comparison. Mineralogical composition, clay minerals content, particle size distribution, packing, porosity, forming procedure, and raw material aging are known as intrinsic parameters. Due to the fact that these parameters are cross linked and are usually inter-dependently related to each other, the attempts to set up a criteria for correlation between intrinsic parameters and drying sensitivity has been limited. That was the reason why the estimation of the cracking tendency was linked with the easiness of the drying process in each reported method. The most applied methods for estimation of the drying sensitivity of clays in the ceramic industry were proposed by Bigot, Ratzenberger, Piltz, Hermansson and Varlamov. The fact that previously mentioned methods were not compared up till know has defined the main objective of this study. The only reported comparison was between Bigot and Ratzenberg drying sensitivity index. The second objective of this review was to present these methods and to estimate the drying behavior of tree different clay raw material. It was confirmed that Varlamov method is very simple, accurate and fast. It is correlated with the mineralogical composition of clay and cannot be used for description of the drying kinetic. The other two models can provide info about the drying kinetic. Piltz model is the most relevant for describing the drying behavior at the beginning of the drying. The results have confirmed that the most suitable conclusion about the drying behavior of the tested clays is obtained when results from Bigot, Piltz and Varlamov methods are available.