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Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on June 29, 2016 | http://pubs.acs.org Publication Date: May 5, 1996 | doi: 10.1021/ba-1996-0251.ch014
Nature and Fate of Oil Sands Fine Tailings Randy J. Mikula , Kim L. Kasperski , Robert D. Burns , and Mike D. MacKinnon 1
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Fuel Processing Laboratory, Western Research Centre, CANMET, P.O. Bag 1280, Devon, Alberta T0C 1E0, Canada 1
Suncor Oil Sands Group, P.O. Box 4001, Fort McMurray, Alberta T9H 3E3, Canada 2
Syncrude Canada Ltd., P.O. Box 5790, Station L, Edmonton, Alberta T6C 4G3, Canada 3
The chemical and physical properties of clay suspensions produced during oil production from oil sands are described. With a com position of approximately 70 wt% water (with some unrecovered bitumen) and 30 wt% solids (>90% less than 44 μm in size), these clay suspensions consolidate very slowly. Clay aggregate or floc morphology has been shown to be a function of the water chemistry and can be manipulated to produce a tailings suspension that is easier to consolidate and dewater. Commercial oil sands processing has been going on in northeastern Alberta since 1967, and in that time approximately 250 million m of this difficult to dewater clay suspension has been produced. The reclamation options for this material (mature fine tailings) on a commercial scale are also outlined. 3
( C O N T I N U E D D E V E L O P M E N T O F T H E L A R G E O I L S A N D S D E P O S I T S found i n
northeastern A l b e r t a is critical i n meeting Canada's present and future energy requirements. A t present, two commercial oil sands processing plants are i n operation i n the Athabasca o i l sands deposit (Figure 1). Great Canadian O i l Sands (now Suncor O i l Sands Group) started pro duction in 1967, whereas Syncrude Canada L t d . started in 1978. T h e combined production of synthetic crude oil (SCO) b y Syncrude and Suncor is more than 250,000 barrels (about 40,000 m ) per day, w h i c h represents over 1 5 % of Canada's crude o i l requirements. Syn crude Canada L t d . processes bitumen and produces S C O at about three 3
0065-2393/96/0251-0677$18.75/0 © 1996 American Chemical Society
Schramm; Suspensions: Fundamentals and Applications in the Petroleum Industry Advances in Chemistry; American Chemical Society: Washington, DC, 1996.
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SUSPENSIONS: F U N D A M E N T A L S & APPLICATIONS IN P E T R O L E U M INDUSTRY
Figure 1. Map showing the location of the Athabasca oil sands deposit and the Syncrude and Suncor extraction operations. times the rate of Suncor (Table I). Since commercial operations began in 1967, a total of over 1 billion barrels of S C O have been produced from the processing of more than 2 billion tonnes of oil sand (Figure 2). A schematic illustrating the relationship between mining, extraction, and tailings i n the o i l sands operations is shown i n F i g u r e 3. O i l production from the o i l sands more closely resembles a mining operation than a conventional o i l development. T h e o i l sands are m i n e d from open pit mines at rates of about 4 5 0 , 0 0 0 tonnes per day (Table I). A t both plants, bitumen is separated from the ore using the Clark hot Table I.
Average A m o u n t of M a t e r i a l s H a n d l e d D a i l y at the Syncrude and Suncor O i l Sands Operations i n 1993
Materials
Syncrude
Suncor
O i l sand processed (t) Average grade of O S (wt % bitumen) B i t u m e n extracted (m )° Synthetic crude o i l p r o d u c e d (m )° Rejects from extraction (t) Total tailings (t) Tailings sand (>22 μπι) (t) Tailings fines (22 μπι) sand component and a fines (
