Microstructural Study of Some Kaolin by Warren-Averbach and Williamson-Hall Methods

Abstract

In this work, we have studied two kaolins from different origins. The first one denoted M1 consists of two main phases (kaolinite and halloysite) and the other M2 whose main constituents are kaolinite, quartz and mica. Using the diffraction of X rays technique, our choice was set on the component of Kaolinite because of the existence of the latter in both kaolins. Lorentz-Polarization correction was carried out on the diffraction data, which has been achieved using LWL program. The corrected profile was extracted using this program. The methods used for the micro structural analysis of the constituents in the two kaolins are those of Warren-Averbach and Williamson-Hall. Scherrer's relationship has been applied in cases where the compound is devoid of strains. The study revealed that the Kaolinite of M1 is devoid of micro constraints, while similar analysis has shown that the Kaolinite in M2 incorporates the strains. This was confirmed by the Williamson-Hall method as well as Fourier analysis. The evaluation of strains in the kaolinite of M2 has been done by the method of Warren-Averbach and the Williamson-Hall diagram. The average value of this constraint found by the first method gave us 0.15 and 0.21 by the second method. The average size of crystallites of the Kaolinite in M1 was found to be in the range 115-145 Å using the method of Warren-Averbach and about 118 Å by the method of Williamson-Hall, while the size of crystallites in M2 was respectively 98 Å and 130 Å using the two methods. The study of the size distribution showed that the dominant size of kaolinite in M1 and M2 is about 40 Å (42%) and 58 Å (32%) respectively