fine coal recovery process optimisation
TRANSCRIPT
Fine CoalFine Coal RecoveryRecoveryProcess OptimisationProcess Optimisation
Some Recent Experiences with Froth Flotation
Custom Reagent Services Pty Ltd
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What Does CRS Do?What Does CRS Do?
Support plant operators Design and supervise laboratory and plant trials Supply customised flotation reagentsDevelop and customise automatic reagent dosing systems
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CRS ReagentsCRS Reagents
Safety of our people and those of our customers is paramountAll CRS brand reagents have a flash point in combustible liquid range or aboveWe specifically avoid the use of low flash point chemicalsRaw materials are readily available from a number of local suppliersProducts are relatively easy to blendProducts have good shelf life
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FineFine Coal Recovery FactsCoal Recovery Facts
Most fine coal will float but response variesNo two flotation plants perform the sameThere are no “silver bullets” but certain reagents are suited to particular plants Reagent cost is minor compared to the value of the coal recoveredSimple but very successful reagent dosing systems exist and are in operationOverdosing can have disastrous effectsUnderdosing results in coal loss
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Custom Reagent Services - Reagent DevelopmentAsh/Yield Relationship - Bulli Seam Coal
75
80
85
90
7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5
Concentrate Ash %
Prod
uct Y
ield
%
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Automatic Reagent AdditionAutomatic Reagent Addition
Three stage system:Primary dose rate based on a feed forward control mechanismSecondary reagent dose rate controlled by both feed forward and “weak link” monitoringThird stage constant set point with on – off control based on “weak link”
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Benefits of Automatic Benefits of Automatic Reagent AdditionReagent Addition
Reagent dose rate continuously adjusted to meet “real time” plant conditionsFlotation performance optimised within froth handling capacity of the plantReduced chemical wastage through minimisation of overdosingImproved plant safety with elimination of operator exposure to hazardous substances
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Primary Reagent Dose Relationship
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
0 50 100 150 200 250 300 350 400 450
Primary Dose (cc/min)
Feed
(tph
)
-3 -2 -1 0 1 2 3
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Tailings ThickenerTailings Thickener
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Bulli Seam Flotation Bulli Seam Flotation –– August 2004August 2004
0
5
10
15
20
25
30
Feed
Mas
s %
Plus 1.
0 ww
1.0 w
w x 0.5
ww
0.5 w
w x 0.5
0.5 x
0.25
0.25 x
0.12
50.1
25 x
0.075
Minus 0
.075
Size Fraction (mm)
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Bulli Seam Flotation Bulli Seam Flotation –– August 2004August 2004
6.0
7.0
8.0
9.0
10.0
11.0
12.0
Feed
Ash
%
Plus 1.
0 ww
1.0 ww x
0.5 ww
0.5 w
w x 0.5
0.5 x
0.25
0.25 x
0.12
50.1
25 x
0.075
Minus 0
.075
Size Fraction (mm)
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Bulli Seam Flotation Bulli Seam Flotation –– August 2004August 2004
30%
40%
50%
60%
70%
80%
90%
100%
Yie
ld
Plus 1.
0 ww
1.0 w
w x 0.5
ww
0.5 w
w x 0.5
0.5 x
0.25
0.25 x
0.12
50.1
25 x
0.075
Minus 0
.075
Size Fraction (mm)
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Bulli Seam Flotation Bulli Seam Flotation –– August 2004August 2004
0
100200300400
500600700800
Effic
ency
Inde
x
Plus 1.0
ww1.0
ww x
0.5 w
w0.5
ww x
0.50.5
x 0.2
50.2
5 x 0.
125
0.125
x 0.0
75Minus 0
.075
Size Fraction (mm)
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Bulli Seam Coal Preparation PlantFlotation Yield (10 day moving average)
August - September 2004
70%
75%
80%
85%
90%
95%
1-Aug 6-Aug 11-Aug 16-Aug 21-Aug 26-Aug 31-Aug 5-Sep 10-Sep
YIEL
D
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Supply Process AlternativesSupply Process Alternatives
Use Diesel and MIBC or other chemicals –direct purchase from supplierCasual supply of customised blend or blends of reagent - supplied on a purchase order numberContract customised reagent supply –consignment stock arrangementSupply Alliance - outcomes agreed and based on sharing risk in good faith
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Supply Alliance ProcessSupply Alliance Process
The customer and the reagent supplier agree outcomes based on principles of good faith and trust and establish processes for:
Determination of common objectives and outcomesCandid sharing of information, knowledge and skillsProportioning costs and sharing profit Achieving gains through innovationEfficient use of expertise and resources availableDevelopment of mutual trust and respect
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Contributions to theContributions to the
““AlliancingAlliancing”” ProcessProcessTechnical Support
Select reagent/reagents best suited to the process and to the coal being treatedProvide reagent dosing strategy, including development of innovative automatic real time dose response techniquesSupport plant operators – risk minimisation, training, process optimisation
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Contributions to theContributions to the
““AlliancingAlliancing”” ProcessProcessPlant Operator
Supplies all hardware, including storage tanks, pumps etc to appropriate site standardsNegotiates directly with chemical suppliers with assistance from the technical supportProvides sampling and testing resourcesMaintains plant performance records for review and assessment
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Alternative Fine Coal Alternative Fine Coal Recovery ProcessRecovery ProcessA process to treat waste streams containing
ultrafine coal particles
High intensity pretreatment processEnhanced conventional flotation“Low cost” heavy oil type reagentRelative high reagent dose rateHigh rate of coal fines captureHandleable product resultsBarren tailings produced
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Fine Coal RecoveryFine Coal RecoverySmall Scale Plant Trial ResultsSmall Scale Plant Trial Results
Feed Ash % (adb) 56.7Feed Pulp Density (%w/w) 3.5Flotation Tails Ash % 76.0SBC Product Moisture % 30.2SBC Product Ash % 12.3SBC Centrate Ash % 88.0Flotation Yield % 32.1Integrated Process Yield % 30.3Combustible Recovery % 61.4
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Concentrate Laser SizingConcentrate Laser Sizing
0102030405060708090
100
1 10 100 1000
Size (microns)
Cum
ulat
ive
% p
assi
ng
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Dewatering BenefitDewatering BenefitBench Scale TestingBench Scale Testing
10
15
20
25
30
35
40
45
50
1 10 100 1000 10000
Form Time (secs)
Moi
stur
e %
Conventional Froth Concentrate
Oil Pretreated Froth Concentrate
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SummarySummaryA proven simple and effective automatic reagent dosing system is available that has produced consistent high operating efficiencies over an extended period.Effective flotation reagent products exist and a number of supply methods available.Fine coal recovery process is enhanced with use of high intensity pretreatment of flotation feed at pilot plant scale.
Is Flotation Yield Is Flotation Yield Improvement Worth Improvement Worth Chasing?Chasing?
Consider Benefits of“Real Time” Reagent Dose Response