Innovative Processing for Stockpile Ash - UKQAA · 2015. 11. 3. · 21st October 2015 . Topics...

Innovative Processing for Stockpile Ash

UKQAA Presentation

21st October 2015

Topics Covered

• Material samples and characterisation

• Wet storage studies

• Initial laboratory processing studies

• Initial concrete tests

Summary Project Flow Chart

Innovative Processing of Stockpile Fly Ash

Laboratory Conditioning Study

Laboratory Scale Processing

Use in Cementitious Systems

Full-scale Tests

Practical Guidelines

Literature Review

Characterisation Stockpile Fly Ash

PHASE 0

PHASE 1

PHASE 2

PHASE 3

PHASE 4

PHASE 5

Materials Received to Date

Material received from 11 sources :

• 8 dry fly ashes

• 6 Stockpile fly ashes

• 8 Lagoon fly ashes

Material Characterisation

Property DFA 1 DFA 2 DFA 3 DFA 4

Fineness:% (45 µm) 33.8 8.1 5.7 19.1

LOI: % 8.3 3.3 9.9 14.4

Water Demand: % 97 96 100 109

Moisture Content: % 0.1 0.1 0.7 0.5

d10 2.5 1.6 0.9 2.7

d50 39.4 11.5 4.7 28.4

d90 199.4 62.7 153.4 132.4

Dry Fly Ashes


Property DFA 5 DFA 6 DFA 7

Fineness:% (45 µm) 18.5 18.3 21.2

LOI: % 13.6 3.9 6.8

Water Demand: % 104 100 100

Moisture Content: % 0.0 0.1 0.2

d10 2.6 2.7 2.6

d50 26.1 20.5 26.4

d90 81.5 82.0 103.1

Dry Fly Ashes


Dry Fly Ashes: Particle Size Distribution

0

1

2

3

4

5

6

0.1 1 10 100 1000

Vo

lum

e (%

)

Particle diameter (µm)

DFA 1 DFA 2 DFA 3 DFA 4 DFA 5 DFA 6 DFA 7

SEM Images

Dry Fly Ashes: x2000 Magnification

DFA 1 DFA 2


Property SFA 1 SFA 2 SFA 3 SFA 4

Fineness:% (45 µm) 49.0 39.9 53.7 24.8

LOI: % 9.7 8.9 10.6 15.1

Water Demand: % 109 109 109 108

Moisture Content: % 12.7 21.1 17.7 15.8

d10 3.2 3.5 3.2 3.5

d50 31.3 38.7 30.9 28.9

d90 128.8 140.9 130.1 94.5

Stockpile Fly Ashes


Stockpile Fly Ashes: Particle Size Distribution

0

1

2

3

4

5

6

0.1 1 10 100 1000

Vo

lum

ne

(%)

Particle Diameter (µm)

SFA 1 SFA 2 SFA 3 SFA 4

SEM Images

Stockpile Fly Ashes: x2000 Magnification

SFA 1 SFA 2

SEM Images

Stockpile Fly Ashes: x2000 Magnification

SFA 3 SFA 4

Lime consumption by fly ash (BS EN 196-5)

MATERIALS QUANTITY

Porland cement, g 15

Fly ash, g 5

De-ionized water, ml 100

Test temperature, °C 40 ± 2

Exposure period, days 8 and 15

Lime consumption by fly ash (BS EN 196-5)

0

2

4

6

8

10

12

14

16

18

20

35 45 55 65 75 85 95

Calc

ium

oxid

e m

mol

Hydroxyl ion concentration mmol

Saturation…

Pass

Fail


Dry Fly Ashes: Pozzolanic Activity

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

8 15 20 8 15 20 8 15 20 8 15 20 8 15 20 8 15 20

DFA 1 DFA 2 DFA 3 DFA 4 DFA 5 DFA 6

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Stockpile Fly Ashes: Pozzolanic Activity

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

30.00

40.00

8 15 20 8 15 20 8 15 20 8 15 20

SFA 1 SFA 2 SFA 3 SFA 4

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Fail


Wet Storage Studies

• Dry Fly Ash moistened in laboratory at various levels (10, 15 and 20%)

• Stored in sealed plastic bags in drums

• Kept in a controlled environment at 20 oC

• Periodically removed and characterised

Wet Storage Studies

Property DFA 5 LS 10% Initial Moisture Content

0 day 1 day 7 day 1 month 3 months

Fineness:% (45 µm) 18.5 19.5 19.4 24.7 43.2

LOI: % 13.6 14.3 13.9 15.5 14.4

Moisture Content: % 10.0 9.8 8.6 8.8 8.7

d10 2.6 2.7 2.8 3.9 4.8

d50 26.1 23.6 24.4 26.3 27.8

d90 81.5 75.6 78.0 80.3 78.8

DFA 5 LS Material Characteristics

Wet Storage Studies

DFA 5 LS Material Characteristics

Property DFA 5 LS 20% Initial Moisture Content

0 day 1 day 7 day 1 month 3 months

Fineness:% (45 µm) 18.5 21.8 23.1 26.9 41.8

LOI: % 13.6 14.8 15.1 14.9 15.6


d10 2.6 2.7 2.6 3.3 4.2

d50 26.1 27.5 25.7 27.6 28.7

d90 81.5 86.5 82.2 85.3 87.3

Wet Storage Studies

Property

DFA 1 LS 10% Initial

Moisture Content

DFA 3 LS 10% Initial

Moisture Content

0 day 3 month 6 month 0 day 3 month 6 month

Fineness:% (45 µm) 33.8 54.5 56.5 5.7 30.5 33.2

LOI: % 8.3 9.0 8.7 5.5 5.9 6.7

Moisture Content: % 10.0 8.6 8.4 10.0 9.3 8.8

Water Requirement: % 97 108 110 100 105 107

d10 1.6 6.0 - 0.9 4.1 7.7

d50 11.9 40.7 - 6.1 24.3 32.3

d90 59.5 164.3 - 92.5 83.8 97.4

DFA 1 LS and DFA 3 LS Material Characteristics

Wet Storage Studies

Change in Moisture Content and Fineness During Storage

DFA 4 LS

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90

Fin

enes

s (4

5µ

m r

eten

tio

n, %

)

Mo

istu

re C

on

ent

(%)

Storage Duration (days)

DFA 4 LS 10% MC DFA 4 LS 20% MC

DFA 4 LS 10% Fineness DFA 4 LS 20% Fineness

Wet Storage Studies


DFA 5 LS

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 10 20 30 40 50 60 70 80 90

Fin

enes

s (4

5µ

m r

etai

ned

, %)

Mo

istu

re C

on

ent

(%)


DFA 5 LS 10% MC DFA 5 LS 15% MC DFA 5 LS 20% MC

DFA 5 LS 10% Fineness DFA 5 LS 15% Fineness DFA 5 LS 20% Fineness

Wet Storage Studies


DFA 1 and DFA 3

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 20 40 60 80 100 120 140 160 180

Fin

enes

s (R

etai

ned

, %)

Mo

istu

re C

on

ten

t (%

)


DFA 1 LS 10% MC DFA 3 LS 10% MC

DFA 1 LS 10% Fineness DFA 3 LS 10% Fineness

Wet Storage Studies

Particle Size Distribution of DFA 5 LS 10%

0

1

2

3

4

5

6

0.1 1 10 100 1000

Perc

enta

ge V

olu

me

(%)


Dry 1 day 7 day 1 Month 3 Months

Wet Storage Studies


0

1

2

3

4

5

6

0.1 1 10 100 1000

Perc

enta

ge V

olu

me

(%)


Dry 1 day 7 day 1 Month 3 Months

Wet Storage Studies


0

1

2

3

4

5

6

0.1 1 10 100 1000

Vo

lum

e (%

)

Particle size distribution (µm)

Dry 3 months 6 months

Wet Storage Studies

Change in Pozzolanic Activity During Storage

DFA 1 LS and DFA 3 LS

-43.2

23.0

38.4 37.3

-74.5

-52.9

-17.1

-1.6

-74.5

-56.5

-23.0

-1.8 -5.9

23.1

31.4 37.3

-74.5

-35.3

12.2 22.9

-95.6

-49.5

-11.8

3.8

-110-100

-90-80-70-60-50-40-30-20-10

01020304050

4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20

DFA 1 DFA 1 LS-3 DFA 1 LS-6 DFA 3 DFA 3 LS-3 DFA 3 LS-6

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%) Pass

Fail

Initial Conclusions

• Around 20% of the initial moisture content of stored fly ash

was lost within the first 7 days beyond which the moisture

content remains constant

• Moisture is believed to become bound within the fly ash

and is not removed by oven drying at 105°C but is when

testing for LOI at 975°C

• The rapid decrease in moisture content did not coincide with

an immediate decrease in fineness due to agglomeration.

• The decrease in fineness was noted to slow at 3-6 month

storage and further change was minor beyond 6 months

Wet Storage Studies

Initial Conclusions

• Water requirement of the stored fly ash increased as storage duration increased

• Moistening and storing fly ash reduced lime consumption and this effect increased with storage period

• After 6 months, laboratory moistened and stored sample results were found to be comparable to stockpile fly ash material

• Similar effects were generally noted for the three moisture contents tested, 10, 15 and 20%

Wet Storage Studies

Laboratory Processing Studies

Wet Fly Ash dried in oven at 105 oC then,

• Ground in ball mill

• Passed through an air jet mill

• Passed through a 63 µm sieve

• Thermally treated at 600 to 700 oC


Property SFA 1 SFA 1

SJM

SFA 1

BM10

SFA 1

BM20

SFA 1

BM30

SFA 1

BM40

Fineness:% (45 µm) 49.0 7.4 12.1 4.11 2.7 1.3

LOI: % 9.7 9.7 9.9 9.6 9.9 9.8

Water Demand: % 109 100 100 100 99 100

Moisture Content: % 12.7 0.0 0.0 0.0 0.0 0.0

d10 3.2 2.0 1.9 1.7 2.0 1.8

d50 31.3 9.5 14.8 14.0 12.0 11.4

d90 128.8 31.8 61.1 49.8 41.0 37.4

Characterisation of Ground SFA 1 Material


Characterisation of Ground SFA 2 Material

Property SFA 2 SFA 2

BM10

SFA 2

BM20

SFA 2

BM30

SFA 2

BM40

Fineness:% (45 µm) 39.9 13.9 7.2 4.4 3.7

LOI: % 8.9 8.9 8.9 8.9 8.9

Water Demand: % 109 100 100 100 100


d10 3.5 1.9 2.0 1.9 1.7

d50 38.7 17.8 15.1 13.9 12.1

d90 140.9 68.6 50.3 44.8 42.1


Particle size distribution of Ground SFA 1 Materials

0

10

20

30

40

50

60

70

80

90

100

0 1 10 100 1000

Pass

ing

(%)


SFA 1 SFA 1 BM10 SFA BM20 SFA 1 BM30 SFA 1 BM40 SFA 1 SJM


Particle size distribution of Ground SFA 2 Materials

0

10

20

30

40

50

60

70

80

90

100

0 1 10 100 1000

Pass

ing

(%)


SFA 2 SFA 2 BM10 SFA 2 BM20 SFA 2 BM30 SFA 2 BM40

SEM Images

Stockpile x2000 Magnification

SFA 1 BM10

SFA 1 BM20

SFA 1

SEM Images

Stockpile x2000 Magnification

SFA 1 BM30

SFA 1 SJM

SFA 1

Bulk Oxide Composition

XRFS Bulk Oxide Composition Fly Ash Samples

Compound (%) SFA 1


Pozzolanic Activity of Ground SFA 1 Materials

-74.5

-56.5

-23.0

-1.8

5.6

13.4 17.2

-4.5

19.8 29.4

-34.1

16.9

23.2 21.3

-38.5

23.6 23.0 25.3

-34.3

17.6 18.4 23.4

-80

-60

-40

-20

0

20

4 8 15 20 8 15 20 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20

SFA 1 SFA 1 SJM SFA BM10 SFA 1 BM20 SFA 1 BM25 SFA 1 BM30

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%) Pass

Fail


Pozzolanic Activity of Ground SFA 2 Materials

-95.6

-49.5

-11.8

3.8

-50.5

8.6 4.4

15.0

-48.5

9.3 14.9 14.7

-41.8

9.8

16.5 20.5

-100

-80

-60

-40

-20

0

20

4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20

SFA 2 SFA 2 GM20 SFA 2 GM25 SFA 2 GM30

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Fail

Activity Index (BS EN 450-1)

28-day Activity Index Pass/Fail

SFA 1 74.3 Fail

SFA 2 72.2 Fail

SFA 1 BM20 83.7 Pass

SFA 2 BM20 78.3 Pass

Grinding gives a 13% increase in activity index for

SFA 1 and a 9% increase for SFA 2 at 28-days over

unprocessed stockpile fly ashes


Property SFA 1


Pozzolanic Activity of Sieved SFA 1 and SFA 2 Materials

-56.5

-23.0

4.7

19.2

-49.5

-11.8

3.7

15.8

-60

-50

-40

-30

-20

-10

0

10

20

8 15 8 15 8 15 8 15

SFA 1 SFA 1


Thermally Treated Stockpile Material

0

2

4

6

8

10

12

LOI (

%)

LOI after thermal treatment

SFA 1 LOI (%) SFA 2 LOI (%)


Pozzolanic Activity of Thermally Treated SFA 1 Materials

-56.5

-23.0

-35.8

-0.5

-30.7

-5.8

-32.1

-7.0

-27.9

-10.1

-33.1

0.7

-27.5

-2.2

-21.8

-7.6

-31.2

-2.3

-60

-50

-40

-30

-20

-10

0

8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15

SFA 1 TH600-45

TH600-60

TH700-45

TH700-60

TH600-45-C/H

TH600-60-C/H

TH700-45-C/H

TH700-60-C/H

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Fail


Pozzolanic Activity of Thermally Treated SFA 2 Materials

-49.5

-11.8

-29.1

9.2

-29.0

7.7

-22.4

9.1

-25.7

4.5

-26.3

12.4

-21.4

14.0

-15.0

3.4

-19.2

7.6

-55

-45

-35

-25

-15

-5

5

15

8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15

SFA 2 TH600-45

TH600-60

TH700-45

TH700-60

TH600-45-C/H

TH600-60-C/H

TH700-45-C/H

TH700-60-C/H

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Fail


Pozzolanic Activity of Ground and Thermally Treated

Stockpile and Laboratory Stored Materials

-74.5

-52.9

-17.1

-1.6

-60.2

-13.0

12.8 14.6

-62.5

-23.0

19.8 20.4

-74.5

-35.3

12.2

22.9

-67.7

9.5

18.5 26.6

-58.6

3.3

20.4 18.5

-95.6

-49.5

-11.8

3.8

-69.3

-11.6

15.1

23.6

-67.8

-11.9

14.4

14.5

-120

-100

-80

-60

-40

-20

0

20

40

4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520

Unprocessed BM20 BM+TH Unprocessed BM20 BM+TH Unprocessed BM20 BM+TH

DFA 1 LS-6 DFA 3 LS-6 SFA 2

Cal

ciu

m O

xid

e W

RT

Satu

rati

on

Cu

rve

(%)

Pass

Fail

Initial Conclusions

• After 20 minutes grinding (ball mill) the fineness of fly ash samples was found to be less than 12% retained regardless of initial fineness, beyond 20 minutes grinding is does not give further significant increases in fineness

• Sieving using a 63µm mesh resulted in an increase in all stockpiled samples fineness, to lower than 12% retained, and reduced LOI by a small degree in most cases however not in SFA 4

• Sieving gave low useable yields of between 20-50% from stockpile fly ash


Initial Conclusions

• Improvements in water requirement can be obtained

from grinding, sieving and thermal treatment

• Grinding, sieving and thermal treatment all increased

lime consumption following the BS EN 196-5 test

methods

• The most effective furnace temperature and duration

for thermal treatment tested was found to be 600°C for

45 minutes allowing the fly ash to be heated and

cooled with the furnace


Previous Concrete Results (2005)

Stockpile and Lagoon Fly Ashes

Concrete Compressive Strengths

y = 0.1229x + 26.132 R² = 0.8078

24

26

28

30

32

34

36

0 10 20 30 40 50 60 70

Particles < 10 μm, %

Original 63 µm sieved Air-classified Ground

L

C A

L

C A

L C

A

L

C

A

28

Day

s C

om

pre

ssiv

e S

tre

ngt

h (

MP

a)

w/c ratio 0.53

Concrete Mix Proportions

Mix Proportions (kg/m3)

Total Cement

PFA % PC PFA Free Water Aggregate

Sand W/C Ratio

20-10mm 10-5mm

350 30 245 105 175 805 405 650 0.5

All mixes included superplasticizing admixture ranging from 0.2% for ground stockpile fly ash up to 0.5% by mass of cement for unprocessed stockpile fly ash.

Admixture Required to Obtain S3 Slump

y = 0.3214x + 10.257 R² = 0.8624

0

5

10

15

20

25

30

0 10 20 30 40 50 60

Ad

mix

ture

(g)

Fineness (% retained)

Stockpile Beneficiated Stockpile Linear (All)

Concrete Strength

Ball Mill Grinding Concrete Compressive Strengths

19.6 20.4 19.8

17.2

18.9 19.8 20.7

19.0

28.4 26.3

23.4 25.6

24.3 24.1

27.5

24.8

38.1 39.0 37.2 38.5

37.3 36.6

40.6 39.1

42.7

45.8

47.9

45.6

0.00

10.00

20.00

30.00

40.00

50.00

60.00

Stockpile BM 10 BM 20 BM 30 Stockpile BM 10 BM 20 BM 30

SFA 1 SFA 2

Co

mp

ress

ive

Stre

ngt

h (

MPa

)

3-day Average 7-day Average 28-day Average 56-day Average

Initial Conclusions

• Previous research suggests that the quantity of

particles less than 10 µm influence concrete strength

• Admixture demand tends to correspond to the fineness

of fly ash following processing

• There is no significant improvement noted in ground

stockpile samples over unprocessed samples until 28

or 56 days where improvements are up to 5 MPa

Concrete Studies

Research Plan for the Next 6 Months

• Literature Review

• Characterisation of test samples

• Wet storage studies

• Continuation of processing

• Continuation of beneficiated fly ash concrete study

• Planning of large-scale trial

Innovative Processing for Stockpile Ash - UKQAA · 2015. 11. 3. · 21st October 2015 . Topics...

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Transcript of Innovative Processing for Stockpile Ash - UKQAA · 2015. 11. 3. · 21st October 2015 . Topics...