Currently, two commercial plants, operating in the Athabasca region of Alberta, produce approximately 20 percent of Canada's petroleum requirements from oil sands. Surface mined oil sand is treated in a water based separation process that yields large volumes of clay tailings with poor settling and compaction characteristics. Clay particles, suspended in the pond water, interact with salts, dissolved from the oil sands ore, to produce mature fine tailings (MFT) containing only 20 to 50 w/w% solids. As a result, large sedimentation ponds are required to produce enough process water to recycle for the plant. Tailings pond dykes can only be constructed during a short summer season. Consequently, the capability to predict production rate and final volume of MFT is essential for mine planning and tailings disposal operations.

Previous research has demonstrated that a small fraction of nano sized clay particles (20 to 300 nm) effectively controls the bulk properties of MFT. These particles are present in the original ore and become mobilized into the water phase during the oil separation process. In this work, the nano sized particles have been separated from the bulk tailings and subjected to a fundamental study of their flocculation behavior in model tailings water.

Photon correlation spectroscopy and a deuterium NMR method were used to follow particle flocculation and gelation processes. These results were correlated with particle settling data measured under the same conditions. It was determined that the nano particles form fractal flocs that eventually interact to give a thixotropic gel. The ultimate sediment volume produced is almost entirely dependent on the original concentration of nano particles while the rate of water release is governed primarily by electrolyte concentration.

Motion of the guest molecules in kaolinite/dimethyl sulfoxide (DMSO) intercalation compounds Al2Si2O5(OH)4∙(CH3)2SO has been studied by means of solid-state nuclear magnetic resonance (NMR) in the temperature range between 300 and 380 K, which is just below the evolution temperature. The 13C magic angle spinning (MAS) NMR spectra show 2 inequivalent methyl carbons: 1 methyl carbon is keyed in the ditrigonal hole of the silicate sheet, while the other is located parallel to the sheet. Above 320 K, the 2 peaks have different intensities, suggesting that the keyed methyl groups from some of the DMSO molecules are released from the hole. The 2H NMR spectra have been measured for kaolinite/DMSO-d6 intercalate. The methyl group of the interlayer DMSO molecule undergoes free rotation around its C3 axis over the temperature range studied. The axis of rotation is fixed at the low temperature (about 160 K), and the methyl group initiates a wobbling motion whose amplitude increases with temperature. The wobbling angles have an anisotropy, estimated from theoretical analysis of the 2H spectral line shapes. The DMSO molecules released from the silicate layer undergo anisotropic rotation of the whole molecule.

Silanol groups in protonated magadiite (H-magadiite) were characterized by 1H and 2H solid-state nuclear magnetic resonance (NMR). H-magadiite and deuterated (D) magadiite were synthesized by the treatment of Na-rich magadiite with 0.2 N HC1 and 0.2 N DC1, respectively. In the 1H NMR spectrum measured at room temperature, silanol groups of H-magadiite showed two signals at 3.75 and 5.70 ppm, indicating that two types of silanol groups were present. The ratio of silanol groups associated with strong hydrogen bonding (5.70 ppm) to those with weaker hydrogen bonding (3.75 ppm) was 2 to 1. The 2H NMR spectra of deuterated magadiite were measured in the temperature range from 150 to 440 K. In the spectra measured at temperatures below 294 K, silanol groups showed Pake doublet patterns. These patterns were composed of two components corresponding to the two types of silanol groups shown in the 1H NMR analysis. Both silanol groups produced wobbling motions with increasing temperature. Above 294 K, the profile of the Pake doublet pattern was transformed gradually to a near triangular pattern, indicating that the silanol groups underwent other motions also, such as a two-site jump.

2H NMR spectra of synthetic deuterated kaolinite have been collected in the temperature range from 150 K to 350 K. Hydroxyl groups show a Pake doublet pattern with an asymmetry factor of 0. They are almost fixed spatially, and undergo a wobbling motion with increasing temperature. The quadrupole coupling constant is 273 ± 3 kHz at 150 K, which indicates that interlayer hydrogen bonding is relatively weak.