Tailing

Reduction of Oil Sands Fine TailingsBaki Ozum

Apex Engineering Inc.Edmonton, Alberta, Canada

and

J. Don ScottDepartment of Civil & Environmental Engineering

University of AlbertaEdmonton, Alberta, Canada

Tailings and Mine Waste 2009 Conference

November 1-4, 2009Calgary, Alberta, Canada

Apex Engineering Inc. University of AlbertaPh. 780-481-8574 E-mail: [email protected] Fax: 780-481-8450

Surface Mineable Oil Sands


oil sands mining followed by ore-water slurry based extractionprocess

bitumen extraction

froth treatment

tailings disposal

refining of bitumen to synthetic crude oil (SCO)

coking followed by hydrotreating

hydrocraking

current bitumen production is about 1,000,000 bbl/d

secure crude oil supply for Canada and USA

mailto:[email protected]


Outline of the Presentation existing bitumen extraction and tailings disposal processes production of mature fine tailings (MFT) reduction of MFT inventory impacts of extraction and tailings disposal processes the

recycled release water chemistry consolidated or composite tailings (CT) technology novel extraction and nonsegregating tailings production

technologies reduce MFT improve recycled release water chemistry

conclusions


Ore Water-Slurry Based Extraction Plants

Extraction TailingsDisposal

(MFT)

Make-up Water

Objectives of Extraction Process high extraction efficiency low grade ore simple, cost effective

Objectives of Tailings Disposal Process minimize MFT production fast settling, robust deposits simple, cost effective

release water recycle rate water chemistry

Oil Sands Ore

additives

additives

Tailings

BitumenFrothTreatment

Froth


additives



Bitumen Extraction and Tailings Disposal ProcessesCommonly Used by the Oil Sands Industry


Clark’s Hot Water Extraction (CHWE) Process

developed by Dr. K. A. Clark and his coworkers at the AlbertaResearch Council in 1930s

made bitumen production commercially feasible Suncor 1967, Syncrude 1978, . . .

uses NaOH as an extraction process aid; increases pH, increases solubility of asphaltic acids which

act as surfactant promoting bitumen recovery efficiency accepted as the only process by oil sands industry CHWE process is used at all four oil sands plants



Problems Associated with CHWE Process causes accumulation of Na+ in the recycled release water NaOH addition causes clay dispersion, produces tailings with

poor geotechnical properties and causes formation of maturefine tailings (MFT)

Energy Resources Conservation Board, Directive 074 demandsreduction of MFT inventory MFT inventory is approaching to 109 m3

MFT consolidates up to 30-35 % solids by mass MFT is about 30 % solids by mass; 85 % water by volume demands large volume of back-up water; 0.5 m3 water/bbl-

bitumen land reclamation problems



Composite Tailings (CT) Technology

composite or consolidated tailings (CT) process was developedat the University of Alberta to reduce MFT inventory

implemented by two major oil sands players requires certain solids contents to prevent segregation whole tailings is fed to cyclones; cyclone underflow and

MFT are blended gypsum (CaSO4) was used to prevent segregation



Composite Tailings (CT) Production

Oil SandsCaustic

Oil SandsTailings

Extraction

CT (Nonsegregating) Deposit

Make-up Water

Release Water Recycle

Gypsum (CaSO4)

Cyclone Overflow(> 70 % Fines)

To Tailings PondProduces Additional MFT

Mature Fine Tailings (MFT)

Bitumen Froth

Cyclone

Cyclone Underflow(7 % Fines)

(From Existing Tailings Pond)



Problems with CT Technology

produces additional MFT from Cyclone Overflow causes H2S emission by anaerobic reduction of SO4

= withresidual bitumen

causes Ca2+ accumulation in the recycled release water



Alternative to CHWE Process:Low Temperature & Non-caustic Extraction Processes

four decades of R & D efforts

reduce /eliminate MFT production

low temperature (<40 oC) and non-caustic extraction process

commercially tested at two plants

Syncrude Canada Ltd.’s Aurora Mine

Albian Sands Muskeg River Mine

commercial experience showed that for acceptable recoveryefficiency:

temperature has to be increased (45 oC – 55 oC)

pH must be increased (additives are needed)

same as the CHWE process



Oil Sands Plants Operations

ExtractionPlant

TailingsDisposal

Release WaterChemistry


how to minimize MFT production?



Novel Bitumen Extraction and TailingsDisposal Processes

Objectives high bitumen extraction efficiency reduce or eliminate MFT producion fast land reclamation reduce recycled release water salinity cost effective, simple to integrate to existing plants and

environmentally friendly


Alternative to Existing Extraction Processes:

Bitumen Extraction by using CaO (Lime) and O3 (Ozone)as Process Aids

or

Bitumen Extraction by using CaO and Biodiesel (BD)as Process Aids

Alternative to Existing CT Process:

Production of Nonsegregating Tailings (NST) from the Blendof Cyclone Underflow, Thickener Underflow and MFT by

using CaO or CaO & CO2 as Process AidsApex Engineering Inc. University of AlbertaPh. 780-481-8574 E-mail: [email protected] Fax: 780-481-8450


Alternative Approach to Bitumen Extraction

extraction temperature >35 oC reduce surface and interfacial tensions:

increase pH by CaO; 150 to 300 mg-CaO/kg-ore dosages produce surfactants by oxidizing bitumen asphaltenes with

O3; 50 to 100 mg-O3/kg-ore dosages use surfactants such as biodiesel (BD) from external sources;

under 200 mg-BD/kg-ore dosages CaO is major additive; O3 or BD are needed for low grade ores

with low bitumen and high fines contents



Experimental

experiments were performed using a Denver D-12Flotation Cell apparatus

water chemistry tests were performed at theDepartment of Civil & Environmental Engineering,University of Alberta



Denver D-12 Flotation Cell



Denver D-12 Flotation Cell



Bitumen Extraction using CaO as Additive


CaO+H2O ↔ Ca(OH)2

Ca(OH)2 ↔ Ca2+ + 2OH-

OH- increases pH, increases solubility of asphalticacids (same as caustic NaOH addition of CHWEprocesses)

surface and interfacial tensions are reduced bitumen-clay attachments are suppressed bitumen-air attachments are promoted clay particles flocculate by Ca2+

2Clay-Na + Ca2+ ↔ (Clay)2-Ca + 2Na+

2Clay-Na + Ca(OH)2 ↔ (Clay)2-Ca + 2NaOH



Bitum e nOre & Tre a tm e nt Froth Bitum e n Re cove ry Bitum e n W a te r S olids

50 o C (g) (g) (%) (%) (%) (%)LC#1AOC0107-12 Blan k 125.4 27.1 92.3 21.6 34.1 45.4AOC0107-13 CaO 60 p p m 128.7 27.8 94.8 21.6 34.9 42.7AOC0107-14 CaO 60 p p m 131.5 28.3 96.4 21.5 35.0 41.7LC #2AOC0107-15 Blan k 128.6 27.7 94.6 21.6 31.7 45.5AOC0107-16 CaO 60 p p m 138.6 28.1 95.7 20.2 33.6 44.7AOC0107-17 CaO 60 p p m 136.5 28.2 96.2 20.7 33.5 44.5LC #2 re pe a te dAOC0107-37 Blan k 142.8 26.6 92.7 18.6 30.3 46.5AOC0107-38 CaO 60 p p m 138.5 28.3 96.7 20.5 33.9 44.3AOC0107-39 CaO 60 p p m 149.7 27.8 95.2 18.6 34.7 45.6LC #3AOC0107-40 Blan k 139.0 28.3 96.5 20.3 33.5 45.1AOC0107-41 CaO 60 p p m 143.0 27.3 93.1 19.1 34.5 44.9AOC0107-42 CaO 60 p p m 151.1 29.2 99.7 19.3 32.9 46.4LC #4AOC0107-43 Blan k 143.2 27.1 92.9 18.9 35.7 45.2AOC0107-44 CaO 60 p p m 135.1 28.2 96.2 20.9 34.0 44.0AOC0107-45 CaO 60 p p m 128.1 27.3 93.3 21.3 35.9 41.0LC #5AOC0107-46 Blan k 138.2 27.8 94.8 20.1 34.4 43.6AOC0107-47 CaO 60 p p m 143.1 28.1 95.9 19.7 31.7 47.5AOC0107-48 CaO 60 p p m 144.3 27.8 95.0 19.3 33.7 45.9

Froth Com position

Bitumen Extraction with CaO and Recycling the Release Water


Water Chemistry from Extraction with CaO and Recycling the Release WaterO re & T re a tm e nt Cond .

50 o C pH (m S ) Tota l HCO 3 Na K M g Ca Chloride S u lfa teRe cycle d w a te rRW 1 8.2 1.492 307 307 441 21 7.8 7.6 171 158RW 2 8.1 1.462 225 225 373 21 8.6 9.7 177 220RW 2 #2 7.9 1.527 230 230 401 22 8.7 9.8 174 213RW 3 7.7 1.479 176 176 354 23 9.4 11.6 180 254RW 4 7.4 1.516 155 155 352 24 12.1 14.7 187 277RW 5 7.5 1.530 137 137 358 24 12.7 15.3 187 293AO C0107-12 Blan k 8.3 1.372 230 230 340 22 9.1 8.4 165 174AO C0107-13 C aO 60 p p m 8.5 1.412 233 227 338 23 9.9 9.6 174 184AO C0107-14 C aO 60 p p m 8.5 1.440 247 241 338 22 10.4 10.2 176 185RW # 2AO C0107-15 Blan k 7.7 1.319 156 156 308 22 10.4 9.5 164 218AO C0107-16 C aO 60 p p m 7.8 1.393 169 169 322 24 11.6 12.6 174 231AO C0107-17 C aO 60 p p m 7.9 1.388 170 170 326 25 11.8 13.2 172 229RW # 2 re pe a te dAO C0107-37 Blan k 7.8 1.406 152 152 300 22 12.0 10.9 175 243AO C0107-38 C aO 60 p p m 7.9 1.479 171 171 335 22 12.8 13.3 176 250AO C0107-39 C aO 60 p p m 7.9 1.474 171 171 312 23 13.2 13.1 181 252RW # 3AO C0107-40 Blan k 7.8 1.404 115 115 297 22 12.8 11.6 176 275AO C0107-41 C aO 60 p p m 8.1 1.484 133 133 310 23 14.1 14.6 184 290AO C0107-42 C aO 60 p p m 8.0 1.487 136 136 314 23 14.0 14.5 184 289RW # 4AO C0107-43 Blan k 7.9 1.516 103 103 313 24 16.3 14.8 192 321AO C0107-44 C aO 60 p p m 8.1 1.523 118 118 334 23 15.6 14.4 184 311AO C0107-45 C aO 60 p p m 8.1 1.525 119 119 309 25 17.0 17.4 191 320RW # 5AO C0107-46 Blan k 7.8 1.533 93 93 316 25 17.8 15.5 196 343AO C0107-47 C aO 60 p p m 7.8 1.544 109 109 303 25 18.7 18.4 195 339AO C0107-48 C aO 60 p p m 7.8 1.529 111 111 330 24 18.3 18.0 187 324

Alka lin ity (m gCa CO 3/L ) Ca tions (m g /L ) An ions (m g /L )



Bitumen Extraction using CaO & O3 asAdditives



Water Chemistry using CaO and O3Bitumen

Ore & Treatment CaO O3 Froth Bitumen Recovery Bitumen Solids Water40 oC (mg/kg-ore) (mg/kg-ore) (g) (g) (%) (%) (%) (%)

Recycled water Oct/07ATL0407-1 Blank 116.9 13.9 60.5 11.9 39.8 48.3ATL0407-2 Blank 113.9 14.2 61.4 12.4 40.6 47.0ATL407-33 CaO 150 - 102.6 12.4 53.6 12.0 43.1 44.9ATL407-34 CaO 150 - 107.6 13.1 56.7 12.1 40.5 47.4ATL407-35 CaO+O3 60s 150 38.4 109.2 14.6 63.5 13.4 39.3 47.3ATL407-36 CaO+O3 60s 150 37.6 111.4 14.3 61.9 12.8 39.4 47.8XXL0107-91 Blank - - 117.8 12.8 52.2 10.8 50.3 38.9XXL0107-92Blank - - 123.3 12.6 51.5 10.2 53.1 36.7XXL0107-89 CaO 150 - 120.7 13.0 53.1 10.7 53.3 36.0XXL0107-90 CaO 150 - 122.2 13.3 54.3 10.9 52.6 36.5XXL0107-87 Ca+O3 60s 150 40.8 125.6 13.5 55.3 10.8 52.1 37.1XXL0107-88 Ca+O3 60s 150 41.6 123.8 13.8 56.4 11.1 52.2 36.7

Froth



Release Water Chemistry from Extraction Tests using CaO and O3

Sample ID CaO pH Cond.(mg/kg-ore) (mS) Total HCO3 Na Mg Ca Chloride Sulfate

RCW-Oct 31-06 8.5 1.560 412 400 361 7.5 7.2 168 88ATL407-1 Blank - 8.4 1.460 308 304 353 11.9 13.4 161 160ATL407-2 Blank - 8.4 1.490 314 310 355 12.4 15.3 169 166AT407-33 CaO 150 8.5 1.480 297 287 356 11.5 13.3 165 173AT407-34 CaO 150 8.6 1.500 301 291 353 11.8 14.2 170 176AT407-35 CaO 150 8.5 1.520 266 260 361 11.0 12.9 168 186AT407-36 CaO 150 8.5 1.509 274 268 361 11.2 13.1 168 176ATL407-1 Blank - 8.4 1.460 308 304 353 11.9 13.4 161 160ATL407-2 Blank - 8.4 1.490 314 310 355 12.4 15.3 169 166XXL0107-87 CaO+O3 60s 150 8.1 1.650 218 218 354 21.9 26.2 170 335XXL0107-88 CaO+O3 60s 150 8.1 1.650 226 226 355 21.1 25.0 173 324XXL0107-89 CaO 150 7.7 1.650 262 262 359 20.7 24.9 173 304XXL0107-90 CaO 150 8.1 1.670 257 257 362 21.6 26.0 174 317XXL0107-91 Blank - 8.0 1.650 250 250 362 21.0 24.2 174 313XXL0107-92 Blank - 8.0 1.620 250 250 354 19.9 22.6 172 299

Anions (mg/L)Alkalinity (mg CaCO3/L) Cations (mg/L)



Sample Sample Average TANID Treatment mg KOH/g Bitumen

ARC1107-Ore-2 Bitumen from 3.52ARC1107-25 80 ppm CaO+O3 3.03ARC1107-27 80 ppm CaO 3.15ARC1107-29 O3 2.96ARC1107-31 Blank (No Additive) 3.13ppm: mg additive/kg-ore

Bitumen Total Acids Numbers (TAN) Data



Bitumen Extraction using CaO & Biodiesel(BD) as Additives

BD, that is, methyl esters of fatty acids with chemicalformula: CmHnCOOCH3 (n<2m+1)

tall oil fatty acids methyl esters; tall oil is a by-product of pulp & paper mills using bleached Kraftprocess

fatty acids monoglycerides may also be added insmall amounts to BD



Results – Biodiesel B100 (BD)on Low Bitumen, High Fines Ore

Treatmentat 40 oC

Amount BDmg/kg ore

Recovery(%)

Corrected(%)

Blank - 73.6 73.6

BD 430 81.8 81.3

BD 870 82.7 81.6

BD 1,667 82.5 80.5

BD 3,333 83.8 79.7

ore composition: 8.13 % bitumen and 19.2 % fines contentsApex Engineering Inc. University of AlbertaPh. 780-481-8574 E-mail: [email protected] Fax: 780-481-8450


Summary CaO based extraction process could be an alternative to

CHWE process provides high bitumen extraction efficiency produces tailings with better geotechnical properties reduces the salinity of recycled release water produces bitumen with low TAN simple, cost effective and environmentally friendly estimated costs of the additives:

CaO, $0.03-$0.06/bbl-bitumen O3, $0.15/bbl-bitumen BD, $0.30/bbl-bitumen



Production of Nonsegregating Tailings (NST)from the Blend of Cyclone Underflow,

Thickener Underflow and MFT by Using CaO orCaO & CO2



Objectives of using CaO or CaO & CO2as Process Additives

produce nonsegregating tailings by formation of yield stress infines-water matrix

high permeability for fast recovery of release water rapid consolidation to achieve shear strength greater than 5 kPa acceptable recycled release water chemistry acceptable soil chemistry for land reclamation



NST Production by using CaO or CaO & CO2

Extraction

Cyclone Overflow(> 70 % Fines)

Cyclone Underflow(7 % Fines)

Thickener Underflow(> 70 % Fines)

CaO or CaO & CO2

NST Mix(14 % to 20 % Fines)

Disposal Pit

RecycleWater

OilSands

Make-upWater

ProcessAids

Thickener

Thickener Overflow(No Fines)

Recycle

MFT, optional)

Cyclone

NonsegregatingDeposit

StoragePond



Low Shearing Segregation Data59 % Solids, SFR 5 and 6, without CaO Treatment

0

0 .2

0 .4

0 .6

0 .8

1

0 2 0 4 0 6 0 8 0 1 0 0

S o l id s C o n te n t P r o f i leE f f e c t o f D if fe r e n t S o l id s & F in e s C o n te n t

E N R 1E N R 2E N R 3E N R 4E N R 5E N R 6

H/H

f

S o l id s C o n te n t, %

A l b ia n S a n d s T a i l in g s



Low Shearing Segregation Data59 % Solids, SFR 5 and 6, with CaO Treatment

0

0 .2

0 .4

0 .6

0 .8

1

0 2 0 4 0 6 0 8 0 1 0 0

S o l id s C o n te n t P r o f i leE f f e c t o f D if fe r e n t S o l id s & F in e s C o n te n t

W ith C a O A d d it io n

E L R 1 0 .6 g /L S F R 5 :1E L R 2 0 .8 g /L S F R 5 :1E L R 3 1 .0 g /L S F R 5 :1E L R 4 0 .6 g /L S F R 6 :1E L R 5 0 .8 g /L S F R 6 :1E L R 6 1 .0 g /L S F R 6 :1

H/H

f

S o l id s C o n te n t, %

A lb ia n S a n d s T a il in g s



NST Production from Aurora Mine Tailings with CaO

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100Solids Content (% )

Nor

mal

ized

Hei

ght,

H/H

f

0 g/L C aO0.2 g/L C aO0.4 g/L C aO0.6 g/L C aO0.8 g/L C aO1.0 g/L C aO

S%=55, F%=16.7



High SolidsPlant Tailings Segregation

Boundary forUntreated Tailings

SandStructureBoundary

Segregation Boundary for LimeTreated Plant Tailings

Possible Mixture of MFTand Plant Tailings orCyclone Underflow

Mature Fine Tails (MFT)

Segregation Boundary for GypsumTreated Tailings Mixture

Segregation Boundary for Acid-Lime Treated Tailings Mixture

Low SolidsPlant Tailings

Cyclone Underflow

Sand/Fines Ratio (SFR)6 5 4 3 2.3 1.7

High SolidsPlant Tailings Segregation

Boundary forUntreated Tailings

SandStructureBoundary

Segregation Boundary for LimeTreated Plant Tailings

Possible Mixture of MFTand Plant Tailings orCyclone Underflow

Mature Fine Tails (MFT)

Segregation Boundary for GypsumTreated Tailings Mixture

Segregation Boundary for Acid-Lime Treated Tailings Mixture

Low SolidsPlant Tailings

Cyclone Underflow

Sand/Fines Ratio (SFR)6 5 4 3 2.3 1.7

Segregation Boundary Diagram



Summary NST production using CaO or CaO & CO2 was tested using Albian

Sands’ Muskeg River Mine and Syncrude Canada Ltd.’s Aurora MineTailings

NST production using CaO or CaO & CO2 is an alternative to presentCT process using CaSO4

CO2 could be introduced or atmospheric CO2 may do the job

produces nonsegregating tailings

eliminates formation of MFT

reduces the salinity of the recovered water; reduces Ca2+ and Mg2+

concentrations

improves the rate of land reclamation

environmentally friendly

estimated costs of the additives:

$0.10/bbl-bitumen; based on 0.8 kg-CaO/m3-NST dosage



Conclusions

existing MFT production and recycled release water salinityproblems could be eliminated by:

Alternative Additives in Bitumen Extraction CaO and O3

CaO and Biodiesel

Tailings Disposal: production of nonsegregating tailings (NST) from the

blend of cyclone underflow, thickener underflow andMFT by using CaO or CaO & CO2 as process additives



Acknowledgments

financial support was provided by: IRAP-NRC; managed by Mr. Ed Polukoshko AERI, managed by Mr. Richard Nelson and Mr. Doug Komery

discussions, suggestions and collaborations by Mr. Brad Komishke,Dr. Dean Wallace and Mr. R.K.O. (Rob) Birkholz of Calgary ResearchCentre-Shell Canada Ltd. are appreciated

collaborations with the University of Alberta, Department of Civil &Environmental Engineering and the Alberta Research Council areacknowledged



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