Colloidal clay gelation: relevance to current oil sands operations

Ultra-fines are predominantly delaminated colloidal clays that exist naturally in oil sands and are released during conditioning of surface mined ores. Critical concentrations of these ultra-fines and the cations present in process water are capable of forming flocculated structures with a very high water holding capacity. During primary separation of bitumen, these ultra-fines are detrimental to recovery as a result of increased slurry viscosity as well as through slime coating of released bitumen. Disposition into tailings ponds eventually produces mature fine tailings. The harmful effects of ultra-fines in some problematic ores are discussed.Peer reviewed: YesNRC publication: Ye