Poster Session

Effect of Particle Size on the Viscosity of Athabasca Clay Suspensions

Sepideh Samiei, MSc student in Chemical Engineering

Supervisor - Dr. Jacob Masliyah and Dr. Zhenge Xu

The success of the separation process conventionally used for oil sands extraction is highly influenced by the viscosity of the oil sands slurry. In the gravity separation vessel, high slurry viscosities can hinder the rise of aerated bitumen and reduce the efficiency of the recovery process. In this study, the role of particle size on the viscosity of oil sands slurries is investigated. Three solids fractions having different particle size distributions were separated from mature fine tails (MFT) and their rheological properties were studied.

For the rheological measurements, dispersions of the three fractions were prepared in the supernatant water decanted from centrifuged MFT to maintain the solution chemistry of the solids. Suspensions of each fraction showed non-Newtonian shear thinning behaviour as well as yield stress that is characteristic of structure formation within the suspensions. For all solids fractions, increasing solids concentration led to higher viscosities and higher yield stress values. According to the viscoelastic properties of the suspensions, stronger solid-like behaviour was observed at higher particle concentrations. Among the three fractions numbered from 1 to 3, fractions 3 with the maximum amount of illite and illite-smectite led to higher suspension viscosities. Also for fraction 3, higher gelling potency was observed at much lower weight fractions as compared to the other fractions.