title: Impact of ozonation on particle aggregation in mature fine tailings.
abstract: The extraction of bitumen from the oil sands in Canada generates tonnes of mature fine tailings (MFT), consisting of a mineral matrix of sand, clay, and water, which without treatment requires thousands of years to fully consolidate. We assessed the performance of a novel ozonation method designed to enhance the settling of MFT and explored the mechanisms involved. The solid content of MFT obtained from oil sands tailings was adjusted to 1, 3, 5 wt % with water before applying 15, 30, and 60 min of ozonation. MFT settled after a short (15 min) ozonation treatment, resulting in a sample with clear released water on the top and condensed sludge at the bottom. The water chemistry characteristics, particles' surface charge and chemical bonding were measured. Ozonation led to the increased organic acids concentrations in MFT suspension through converting of organic matter from high to low molecular weight, and detaching organic coating on MFT particles. The pH and the concentrations of ions in the MFT suspension were changed significantly, an association of metal ions with MFT particles was promoted, and the surface charges of MFT particles were neutralized. Consequently, the MFT suspension was destabilized and MFT particle precipitation was observed.
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2.
authors.forename: Jiaming
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2.
authors.forename: Fahmida
authors.initials: F
authors.lastname: Tumpa
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Pérez Estrada
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2. Electronic address: mgamalel-din@ualberta.ca.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Gamal El-Din
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2. Electronic address: yang.liu@ualberta.ca.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002170:Canada; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019652:Extraction and Processing Industry / Q000379:methods; D006838:Hydrocarbons / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D061329:Oil and Gas Fields; D010126:Ozone / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D006838:Hydrocarbons; D014867:Water; D010126:Ozone; C006647:asphalt
keywords: Consolidation; MFT; Ozonation; Surface property; Water chemistry