Abstract

Studies of kaolinite surfaces are of industrial importance. One useful method for studying the changes in kaolinite surface properties is to apply chemometric analyses to the kaolinite surface infrared spectra. A comparison is made between the mechanochemical activation of Kiralyhegy kaolinites with significant amounts of natural quartz and the mechanochemical activation of Zettlitz kaolinite with added quartz. Diffuse reflectance infrared Fourier transform (DRIFT) spectra were analyzed using principal component analysis (PCA) and multi-criteria decision making (MCDM) methods, the preference ranking organization method for enrichment evaluations (PROMETHEE) and geometrical analysis for interactive assistance (GAIA). The clear discrimination of the Kiralyhegy spectral objects on the two PC scores plots (400–800 and 800–2030 cm⁻¹) indicated the dominance of quartz. Importantly, no ordering of any spectral objects appeared to be related to grinding time in the PC plots of these spectral regions. Thus, neither the kaolinite nor the quartz are systematically responsive to grinding time according to the spectral criteria investigated. The third spectral region (2600–3800 cm⁻¹, OH vibrations), showed apparent systematic ordering of the Kiralyhegy and, to a lesser extent, Zettlitz spectral objects with grinding time. This was attributed to the effect of the natural quartz on the delamination of kaolinite and the accompanying phenomena (i.e., formation of kaolinite spheres and water). The mechanochemical activation of kaolinite and quartz, through dry grinding, results in changes to the surface structure. Different grinding times were adopted to study the rate of destruction of the kaolinite and quartz structures. This relationship (i.e., grinding time) was classified using PROMETHEE and GAIA methodology.

Crystalline quartz as a far-infrared beam splitter for Fourier transform spectroscopy

John C. Brasunas, G. Mark Cushman, and B. Lakew
Appl. Opt. 36(13) 2893-2896 (1997)

Fractional Fourier transformers through reflection

Kurt Bernardo Wolf and Guillermo Krötzsch
J. Opt. Soc. Am. A 19(6) 1191-1196 (2002)

Measurement of the Optical Constants of Crystal Quartz in the Far Infrared with the Asymmetric Fourier-Transform Method*

Edgar E. Russell and Ely E. Bell
J. Opt. Soc. Am. 57(3) 341-348 (1967)

Diffuse reflecting surfaces for the infrared and far infrared

Xiaoming Wang and Jerald R. Izatt
Appl. Opt. 32(25) 4755-4762 (1993)

Attenuated total reflectance measurements of the complex refractive index of kaolinite powder at CO₂ laser wavelengths

R. G. Pinnick, S. G. Jennings, Daniel C. Boice, and John P. Cruncleton
Appl. Opt. 24(19) 3274-3285 (1985)