Novel Processes for Treatment of Syncrude Fine Transition and Marine Ore Tailings

Abstract

Syncrude Canada Ltd. has compiled a substantial amount of work on tailings research and development to determine the most effective treatment and deposition processes to increase reclamation options, water reuse and thermal energy recovery. This research has shown that the conventional processes using a single flocculant, a single coagulant or a coagulant-flocculant combination are ineffective for transition and marine ore tailings. For example, using a single flocculant to treat transition or marine ore tailings resulted in a thickener overflow of 1∼4% solids content compared with the target solids content of <0.5% obtained with estuarine ore. On the other hand, new processes including Coagulation-Flocculation-Coagulation (CFC), Flocculation-Coagulation (FC) and Flocculation-Coagulation-Flocculation (FCF) have been found to be acceptable options. However, the FCF process outperformed the CFC and FC processes because the FCF process produced huge flocs resulting in fast initial settling rates. The key components of these technologies consist of the recipe of chemicals and their sequences of addition. With these technologies, almost all submicron clay minerals are aggregated together and settle as a whole resulting in a clear supernatant of less than 0.13% solids.

Syncrude Canada Ltd. has compiled a substantial amount of work on tailings research and development to determine the most effective treatment and deposition processes to increase reclamation options, water reuse and thermal energy recovery. This research has shown that the conventional processes using a single flocculant, a single coagulant or a coagulant-flocculant combination are ineffective for transition and marine ore tailings. For example, using a single flocculant to treat transition or marine ore tailings resulted in a thickener overflow of 1∼4% solids content compared with the target solids content of <0.5% obtained with estuarine ore. On the other hand, new processes including Coagulation-Flocculation-Coagulation (CFC), Flocculation-Coagulation (FC) and Flocculation-Coagulation-Flocculation (FCF) have been found to be acceptable options. However, the FCF process outperformed the CFC and FC processes because the FCF process produced huge flocs resulting in fast initial settling rates. The key components of these technologies consist of the recipe of chemicals and their sequences of addition. With these technologies, almost all submicron clay minerals are aggregated together and settle as a whole resulting in a clear supernatant of less than 0.13% solids.

Syncrude Canada Ltd. a compilé une quantité substantielle de travaux de recherche et développement sur les rejets afin de déterminer le traitement et les procédés de dépôt les plus efficaces pour augmenter les options de remise en état, de réutilisation d'eau et de récupération de l'énergie thermique. Cette recherche a montré que les procédés conventionnels utilisant un seul floculant, un seul agent coagulant ou une combinaison agent coagulant-floculant sont inefficaces pour les rejets de minerai de transition ou marin. Par exemple, l'utilisation d'un seul floculant pour traiter les rejets de minerai de transition ou marin a résulté en un trop-plein d'épaississeur ayant une teneur en solides de 1∼4% en comparaison avec l'objectif d'une teneur en solides de < 0.5% obtenue avec le minerai d'estuaire. D'un autre côté, on a trouvé que les nouveaux procédés incluant Coagulation-Floculation-Coagulation (CFC), Floculation-Coagulation (FC) et Floculation-Coagulation-Floculation (FCF) étaient des options acceptables. Cependant, le procédé FCF surpassait les procédés CFC et FC parce que le procédé FCF produisait des floculats énormes résultant en des vitesses initiales de sédimentation très rapides. Les composantes clés de ces techniques incluent la recette des produits chimiques ainsi que la séquence de leur addition. Avec ces techniques, presque tous les minéraux d'argile submicroniques sont agglomérés ensemble et sédimentent en un tout résultant en un surnageant clair de moins de 0.13% de solides.