Monitoring of transformations in bentonite after NaOH-TMA treatment

Semi-quantitative methods of X-ray diffraction and FTIR-spectroscopy, accompanied by electron microscopy, X-ray microanalysis and others were used to monitor structural-phase reorganizations occurring in a smectite–gypsum mixture (bentonite) subjected to NaOH treatment with the subsequent addition of quaternary ammonium salt (TMA) in conditions of water deficiency. The interaction of bentonite with NaOH breaks up large bentonite aggregates, saturates smectite with Na cations, and yields Ca(OH)2. The addition of TMA is accompanied by its penetration into the interlayer space and adsorption on the surface.