Innovative Processing for Stockpile Ash UKQAA Presentation 21st - PowerPoint PPT Presentation

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 Characterisation Laboratory PHASE 1 Stockpile Fly Ash Conditioning Study PHASE 2 Laboratory Scale Literature Review Processing PHASE 0 Use in Cementitious Systems PHASE 3 Full-scale Tests PHASE 4 Practical Guidelines 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 Dry Fly Ashes 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 d 10 2.5 1.6 0.9 2.7 d 50 39.4 11.5 4.7 28.4 d 90 199.4 62.7 153.4 132.4

Material Characterisation 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 d 10 2.6 2.7 2.6 d 50 26.1 20.5 26.4 d 90 81.5 82.0 103.1

Material Characterisation Dry Fly Ashes: Particle Size Distribution 6 5 4 Volume (%) 3 2 1 0 0.1 1 10 100 1000 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

Material Characterisation Stockpile Fly Ashes 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 d 10 3.2 3.5 3.2 3.5 d 50 31.3 38.7 30.9 28.9 d 90 128.8 140.9 130.1 94.5

Material Characterisation Stockpile Fly Ashes: Particle Size Distribution 6 5 4 Volumne (%) 3 2 1 0 0.1 1 10 100 1000 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) 20 18 Calcium oxide mmol 16 14 12 Fail 10 8 Saturation… 6 Pass 4 2 0 35 45 55 65 75 85 95 Hydroxyl ion concentration mmol

Material Characterisation Dry Fly Ashes: Pozzolanic Activity 80.0 Pass 70.0 Calcium Oxide WRT Saturation Curve (%) 60.0 50.0 40.0 30.0 20.0 10.0 0.0 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

Material Characterisation Stockpile Fly Ashes: Pozzolanic Activity 40.00 Calcium Oxide WRT Saturation Curve (%) Pass 30.00 20.00 10.00 0.00 -10.00 -20.00 -30.00 -40.00 Fail -50.00 8 15 20 8 15 20 8 15 20 8 15 20 SFA 1 SFA 2 SFA 3 SFA 4

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 o C • Periodically removed and characterised

Wet Storage Studies DFA 5 LS Material Characteristics DFA 5 LS 10% Initial Moisture Content Property 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 d 10 2.6 2.7 2.8 3.9 4.8 d 50 26.1 23.6 24.4 26.3 27.8 d 90 81.5 75.6 78.0 80.3 78.8

Wet Storage Studies DFA 5 LS Material Characteristics DFA 5 LS 20% Initial Moisture Content Property 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 Moisture Content: % 20.0 16.2 15.9 16.1 16.0 d 10 2.6 2.7 2.6 3.3 4.2 d 50 26.1 27.5 25.7 27.6 28.7 d 90 81.5 86.5 82.2 85.3 87.3

Wet Storage Studies DFA 1 LS and DFA 3 LS Material Characteristics DFA 1 LS 10% Initial DFA 3 LS 10% Initial Moisture Content Moisture Content Property 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 d 10 1.6 6.0 - 0.9 4.1 7.7 d 50 11.9 40.7 - 6.1 24.3 32.3 d 90 59.5 164.3 - 92.5 83.8 97.4

Wet Storage Studies Change in Moisture Content and Fineness During Storage DFA 4 LS 60.0 20 Fineness (45µm retention, %) 18 50.0 Moisture Conent (%) 16 14 40.0 12 30.0 10 8 20.0 6 4 10.0 2 0.0 0 0 10 20 30 40 50 60 70 80 90 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 Change in Moisture Content and Fineness During Storage DFA 5 LS 20.0 50.0 Fineness (45µm retained, %) 18.0 45.0 Moisture Conent (%) 16.0 40.0 14.0 35.0 12.0 30.0 10.0 25.0 8.0 20.0 6.0 15.0 4.0 10.0 2.0 5.0 0.0 0.0 0 10 20 30 40 50 60 70 80 90 Storage Duration (days) 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 Change in Moisture Content and Fineness During Storage DFA 1 and DFA 3 10.00 60.0 9.00 50.0 Fineness (Retained, %) Moisture Content (%) 8.00 7.00 40.0 6.00 5.00 30.0 4.00 20.0 3.00 2.00 10.0 1.00 0.00 0.0 0 20 40 60 80 100 120 140 160 180 Storage Duration (days) 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% 6 5 Percentage Volume (%) 4 3 2 1 0 0.1 1 10 100 1000 Particle diameter (µm) Dry 1 day 7 day 1 Month 3 Months

Wet Storage Studies Particle Size Distribution of DFA 5 LS 20% 6 5 Percentage Volume (%) 4 3 2 1 0 0.1 1 10 100 1000 Particle diameter (µm) Dry 1 day 7 day 1 Month 3 Months

Wet Storage Studies Particle Size Distribution of DFA 1 LS 10% 6 5 4 Volume (%) 3 2 1 0 0.1 1 10 100 1000 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 50 Pass 38.4 37.3 31.4 37.3 40 Calcium Oxide WRT Saturation Curve (%) 30 23.0 23.1 22.9 20 12.2 10 3.8 0 -1.8 -1.6 -10 -5.9 -11.8 -20 -17.1 -23.0 -30 -40 -35.3 -50 -43.2 -49.5 -60 -52.9 -56.5 -70 -80 -74.5 -74.5 -74.5 -90 -100 Fail -95.6 -110 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

Initial Conclusions Wet Storage Studies • 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

Initial Conclusions Wet Storage Studies • 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%

Laboratory Processing Studies Wet Fly Ash dried in oven at 105 o C then, • Ground in ball mill • Passed through an air jet mill • Passed through a 63 µm sieve • Thermally treated at 600 to 700 o C

Laboratory Processing Studies Characterisation of Ground SFA 1 Material SFA 1 SFA 1 SFA 1 SFA 1 SFA 1 Property SFA 1 SJM BM10 BM20 BM30 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 d 10 3.2 2.0 1.9 1.7 2.0 1.8 d 50 31.3 9.5 14.8 14.0 12.0 11.4 d 90 128.8 31.8 61.1 49.8 41.0 37.4

Laboratory Processing Studies Characterisation of Ground SFA 2 Material SFA 2 SFA 2 SFA 2 SFA 2 Property SFA 2 BM10 BM20 BM30 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 Moisture Content: % 21.1 0.0 0.0 0.0 0.0 d 10 3.5 1.9 2.0 1.9 1.7 d 50 38.7 17.8 15.1 13.9 12.1 d 90 140.9 68.6 50.3 44.8 42.1

Laboratory Processing Studies Particle size distribution of Ground SFA 1 Materials 100 90 80 70 Passing (%) 60 50 40 30 20 10 0 0 1 10 100 1000 Particle diameter (µm) SFA 1 SFA 1 BM10 SFA BM20 SFA 1 BM30 SFA 1 BM40 SFA 1 SJM

Laboratory Processing Studies Particle size distribution of Ground SFA 2 Materials 100 90 80 70 Passing (%) 60 50 40 30 20 10 0 0 1 10 100 1000 Particle diameter (µm) SFA 2 SFA 2 BM10 SFA 2 BM20 SFA 2 BM30 SFA 2 BM40