Rheological Properties of Asphaltite−Water Slurries

In this study, the rheological characteristics of asphaltite−water slurries (AWSs) were investigated with respect to some of the most important parameters in the preparation of slurries. The effects of pulp density, chemical addition, pulp pH, and particle size on the rheological behavior and viscosity of AWSs were studied. The role of demineralization of asphaltite was also investigated, and rheological properties of raw and relatively demineralized asphaltites were compared. Results showed that viscosity of the AWSs was negatively influenced by increases in the pulp density and as the mean particle size decreased from 104.81 to 15.39 μm. Increases in pH provided reduced viscosity values. The effects of dispersing and stabilizing agents were studied with a chemical mixture including 90% polystyrene sulfonate (PSS) as the dispersant and 10% Na-carboxylmethylcellulose (Na-CMC) as the stabilizer. The change in the viscosity was also investigated as a function of the dosage of the chemical mixture used. Minimum viscosity was achieved with a 1.1% chemical mixture addition, while excess dosages resulted in adverse effects and thickening of the slurry. Studies with raw and demineralized samples showed that mineral matter and hydrophobic aggregation of particles are critical factors, significantly affecting the rheological characteristics of AWSs.