fine coal beneficiation and recovery - doe froth flotation disc filter increasing difficulties....

Center for Advanced Separation Technologies CASTCAST

Workshop on Coal Beneficiation and Utilization of Rejects Initiatives, Policies and Practices

August 22-24, 2007

Fine Coal Beneficiation Fine Coal Beneficiation and Recoveryand Recovery

by

Roe-Hoan Yoon, DirectorCenter for Advanced Separation Technologies


Separation Processes Used for CoalSeparation Processes Used for Coal

SieveBends

Dense Media

Cyclone

BasketCentrifuges

Dense Media Vessel

DewateringScreens

Raw CoalScreens

Coal Spirals Screen-BowlCentrifuges

ClassifyingCyclones

Med

ium

Solid-Solid Solid-LiquidSize-SizeC

oars

eFi

neU

ltraf

ine Froth Flotation Disc Filter

Incr

easi

ng D

iffic

ulti

esIn

crea

sing

Diff

icul

ties


Separation Processes Used for CoalSeparation Processes Used for Coal

Ultr

afin

e

SieveBends

Dense Media

Cyclone

BasketCentrifuges

Dense Media Vessel

DewateringScreens

Raw CoalScreens

Coal Spirals Screen-BowlCentrifuges

ClassifyingCyclones

Med

ium

Solid-Solid Solid-LiquidSize-SizeC

oars

eFi

ne


DeslimeDeslime Flotation CircuitFlotation Circuit

FEED

CLEAN COAL

REJECT

To OtherProcessing

Circuits

Reagents

Flotation Bank

HydrocycloneCentrifuge

ULTRAFINES100 mesh x 0

100 x 325 mesh

325 mesh x 0

effluent


Fine Coal ImpoundmentFine Coal Impoundment

2.5 to 3 billion tons of fine coalIn 713 impoundmentsMostly in Central Appalachia.


Effect of Particle Size on FlotationEffect of Particle Size on Flotation

(Gaudin, 1931)

10 100 10000.0

0.2

0.4

0.6

0.8

1.0

Model (t=3 min) (N=4) (N=12)

Data Bougainville Gaudin Mt.Isa Mt.Lyell

Rec

over

yd1 ( μm)

(Sherrell, Do and Yoon, 2005)

Model PredictionPlant Practice


Particle Top Size (mm)

Cos

t of D

ewat

erin

g ($

/t)

0 1 2 3 4 5 6 70

2

4

6

8

10Ref: Hucko, 1990

VTVT

Cost of DewateringCost of Dewatering


Advanced Coal Processing (1)Advanced Coal Processing (1)Advanced Flotation

Microcel FlotationAdvanced Dewatering

Dewatering Aids• Licensed to Nalco Chemical• Commercialized at Pinnacle

Hyperbaric Centrifuge• Licensed to Decanter Machine• Pilot-scale tests ongoing

Novel Dewatering Technology• Can produce <5% moisture


Bubble Generation in Bubble Generation in MicrocelMicrocel

MicrocelSpargers

Pump

In-LineMixer

BubbleGenerator

MicrocelSpargers

Pump

In-LineMixer

BubbleGenerator

MicrocelSpargers

Pump

In-LineMixer

BubbleGenerator


MicrocelMicrocel at Peak Downsat Peak Downs


0%

2%

4%

6%

8%

10%

12%

Ash

(%)

Target

Time (hours)

Benefits of Using Benefits of Using MicrocelMicrocel at Peak Downsat Peak DownsBefore and After Installation


Ongoing Ongoing MicrocelMicrocel Projects in AustraliaProjects in Australia

Summary of Microcel Projects Site No. of Cells Customer

Collinsville 1 Xstrata Millennium 4 Excel Gregory 5 BMA Dawson 6 Anglo Coal Blackwater 6 BMA Lake Lindsay 2 Anglo Coal Sonoma 1 BMA

From Eriez Manufacturing


Advanced Coal Processing (2)Advanced Coal Processing (2)Advanced Flotation

Microcel FlotationAdvanced Dewatering

Dewatering Aids• Licensed to Nalco Chemical• Commercialized at Pinnacle

Hyperbaric Centrifuge• Licensed to Decanter Machine• Pilot-scale tests ongoing

Novel Dewatering Technology• Can produce <5% moisture


Novel Dewatering AidsNovel Dewatering Aids


Dewatering AidesDewatering Aides

+1 mm Sizing

Feed

Waste

-100 M

CoarseClean

Screen-BowlCentrifuge

Waste

UltrafineColumns

Waste

ReagentConditioner

UltrafineDisc Filter

PrimaryCyclones Ultrafine

Clean

Waste

FineColumns

ReagentConditioner

FineDisc Filter

FineClean

CleanCyclones

DeslimeCyclones

Two-StageSpirals

-325 M

100 x325 M

+100 M


Dewatering AidsDewatering Aids

17

19

21

23

25

27

0 0.50 1.00 1.50

Reagent Dosage (lb/t)

Cak

e M

oist

ure

(%)

LaboratoryIn-Plant


Hyperbaric Filter CentrifugeHyperbaric Filter Centrifuge

DischargeSection

FilterSection

Partition/Outer Seal

DriveMotor

DriveBelt

ReturnLine

3-WayValve

PneumaticCylinder

DischargeRam

FeedLine

SlurryPump

Solenoid

SealAir Inlet

CentrifugeHousing

CentrifugeDrum

Pilot-Scale Prototype

1500 RPM0.15 mm x 013 mm cake

0

5

10

15

20

25

30

0 30 60 90 120

Spin Time (sec)

Moi

stur

e (%

)


0

20

40

60

80

100

0 6 12 18 24 30

Product Ash (%)

Com

bust

ible

Rec

over

y (%

)

-100 mesh-325 mesh

Release AnalysisAssam Coal II

Effect of Particle Size on the Flotation of Indian CoalEffect of Particle Size on the Flotation of Indian CoalAssam Coal 2Assam Coal 2


Effect of Particle Size on the Flotation of Indian CoalEffect of Particle Size on the Flotation of Indian CoalAssam Coal 1Assam Coal 1

Product Ash (%)

Com

b. R

ecov

ery

(%)

0

20

40

60

80

100

0 6 12 18 24 30

28 x 100 mesh-100 mesh-325 mesh

Release AnalysisAssam Coal


Advanced Fine Coal Beneficiation (4)Advanced Fine Coal Beneficiation (4)for Indian Metallurgical Coalfor Indian Metallurgical Coal

SlurryFeed

Note: Not all clarified and

process water streams are

shown.

ExistingPlant

ColumnFlotation

Waste

Four-StageConditioner

Thickener

Disc Filter

Clean Coal

FiltratePump

VacuumReceiver

VacuumPump

Conveyor

SpargerCompressor

RotaryDistributor

ClassifyingCyclones

O/FPumpU/F

PumpFeedSump

RodMill


Effect of Particle Size on FlotationEffect of Particle Size on Flotation

(Gaudin, 1931)

10 100 10000.0

0.2

0.4

0.6

0.8

1.0

Model (t=3 min) (N=4) (N=12)

Data Bougainville Gaudin Mt.Isa Mt.Lyell

Rec

over

yd1 ( μm)

(Sherrell, Do and Yoon, 2005)


Coarse Coal Flotation (1)Coarse Coal Flotation (1)Ofori, Brien, Firth, Jenkins (2005)


MACETM 300 images on Bowen bsain coal

Coarse Coal Flotation (2)Coarse Coal Flotation (2)Ofori, Brien, Firth, Jenkins (2005)


Coarse Coal Flotation (3)Coarse Coal Flotation (3)Less hydrophobic coals drop off.Less hydrophobic coals drop off.


Coarse Coal Flotation (5)Coarse Coal Flotation (5)Indian coal may need a more powerful collector.Indian coal may need a more powerful collector.

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5

Flotation Time, minutes

Com

b. R

ecov

ery,

%

DieselR-9836RU+RW+RW3aPX1+RW+RW3aFA+RW+RW3a

JamadobaJamadobaCoalCoal


Advanced Fine Coal Beneficiation (6)Advanced Fine Coal Beneficiation (6)Split Flotation helps Indian coal.Split Flotation helps Indian coal.

0 2 4 6 8 10 12 14 160

20

40

60

80

100

>65 mesh<65 mesh

Cum

. Yie

ld, %

Flotation Time (min)

Float Separately

Float Together


FrothProduct

C1C2C3C4T

Total

Mass(%)

10.9515.2634.3510.7628.68

100.00

Ash(%)

6.556.889.0717.3291.70

33.05

Mass(%)

10.9526.2160.5671.32100.00

---

Ash(%)

6.556.748.069.4633.05

---

Recovery(%)

15.336.583.296.4100.0

---

Individual Cumulative

Conclusion: Incremental ash <20-25% in flotation, so always pull float cells “hard” (produce grey tails).

Coarse Particle Flotation (7)Coarse Particle Flotation (7)How hard do we float?


Dense Medium Cyclone Dense Medium Bath

SGValue

1.301.351.401.451.501.551.601.651.701.802.00Feed

Mass(%)

31.1228.2713.411.710.900.640.871.031.261.452.9516.38

Ash(%)

4.447.6513.7419.4024.6729.6034.2238.5542.6348.3058.3087.22

CumMass(%)

31.1259.3972.8074.5175.4176.0576.9277.9579.2280.6783.62100.00

CumAsh(%)

4.445.977.407.677.888.068.368.769.3010.0011.7024.07

Mass(%)

5.3211.3216.324.322.351.231.031.241.922.213.2849.46

Ash(%)

4.517.5013.5219.5425.1130.1434.1439.0141.9547.6959.2386.54

CumMass(%)

5.3216.6432.9637.2839.6340.8641.8943.1345.0547.2650.54100.00

CumAsh(%)

4.516.5510.0011.1111.9412.4813.0213.7614.9716.5019.2752.54

Maximizing YieldMaximizing YieldOperation at Constant Incremental Ash


SummarySummaryAdvanced fine coal beneficiation technologies have been developed.

Microcel flotation column• Eriez Manufacturing• Metso Minerals

Fine coal dewatering technologies• Nalco• Decanter

Coarse coal flotation collector• Nalco

For Indian coalsFine coal flotation can produce low-ash products.Coarse coal flotation can help increase yield.

fine coal beneficiation and recovery - doe froth flotation disc filter increasing difficulties....

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