DFT theoretical and FT-IR spectroscopic investigations of the plasticity of clay minerals dispersions

• Correlation of spectral characteristics in MIR range and plasticity of clay is shown.
• Plasticity of clay minerals dispersions were explained using DFT calculations.
• The hydration process of kaolinite was studied.
• H2O on kaolinite is adsorbed primarily at the sites coordinated by 3 hydrogen atoms.

Plasticity is the most important property of dispersions of clay minerals that determine the character of participation of these systems in many natural and technological processes. We report on the results of studies of hydration mechanism in typical clay minerals making part of natural dispersions of sedimentation masses by means of IR spectroscopy and theoretical density functional theory (DFT) methods. X-ray diffraction analysis of clay minerals of Millerovo mineral deposit (Russian Federation) is carried out. Regularities and peculiarities of interaction of water molecules with kaolinite basal planes (001) and (001¯) are analyzed. The role of water in the formation of plasticity of clay minerals dispersions is revealed. The modes of water molecules placement and their state and structure in the system “clay mineral-water” is defined. Phase transition processes of clay minerals dispersion into plastic and liquid state and their influence on spectral characteristics of the systems are investigated. The interpretation of clay minerals phase transitions into plastic and fluid state based on the results of DFT simulation is given. The relation is established between specific variation of spectral characteristics and phase transitions of clay minerals dispersions into plastic and liquid state.

Figure optionsDownload as PowerPoint slide