role of materials development in resource efficiencypage 1 imperial college london chris cheeseman...

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Imperial College London

Chris CheesemanDepartment of Civil and Environmental Engineering Imperial College London

RECIMAT’09 Avances en el Reciclado de

Materiales y Eco-Energía

Role of materials development in resource efficiency

Madrid, 12-13 de Noviembre de 2009

Moderador

Notas de la presentación

This research is part of the project: “Integrated solution for air pollution control residues using DC plasma technology” funded by UK Technology Strategy Board

1. Drivers for innovation

2.

Examples from research at Imperial College LondonSilt from aggregate washingAPC residuesSewage sludge ash

3.

Portland cement and novel low-carbon systems

4.

Conclusions

Presentation

Moderador


Overall project objective: Develop a new, commercially viable, integrated sustainable technology for treating APC residues Minimal environmental impact Transforms the bulk of the APC residues into useful products using DC plasma technology. Research objective: Develop a low energy sustainable geopolymeric material using high amount of DC plasma vitrified APC residues which will have the potential to be used in construction industry

Driver for change and innovation

World population growth

(Source: United Nations 2008)

Predictions for levels of atmospheric CO2

Global warming predictions

We are living in a time of rapid change

CO2

emissionsGlobal warming Population growthExploitation of natural resources

Environmental issues

GovernmentInitiatives

(EU and UK)

Increased cost of energy/transportWaste disposal taxCO2 pricingTaxes on resource extraction

Business Development

and Innovation

Industrial symbiosisBeneficial reuse of wastesSustainable materialsLow-carbon economy

Drivers for change

Increase in UK Landfill Tax -

active waste

Inert waste Landfill Tax is at £

2.50 per tonne

Business drivers are absolutely key

Innovation in resource efficiency

Improved competitiveness

Associated carbon and landfill savings

Next 10 to 20 years represent a huge opportunity

Research challenges and opportunities

Linear system

ProductsNaturalresources

Waste

Conventional industry

Conventional raw materials

Move toward Circular system

Natural resources

Products

Products

Waste

To

Resource

Natural resources

21st

century industry

NISP –

National Industrial Symbiosis Programme

New resources

Industrial wastes

Material cycles and embodied energy

Research needed to make the green arrows happen

CIVIL ENGINEERING

ENVIRONMENTAL ENGINEERINGWASTE MANAGEMENT

MATERIALS SCIENCEAND PROCESSING

RESOURCE EFFICIENCY AND SUSTAINABLE MATERIALS

Industrially focussed applied researchWaste materials as resourcesKey driver is avoiding landfill

Research focus

Cement and concrete

Alkali-activated pozzolans

Geopolymers

Ceramics

Glass-ceramics

Inorganic-organic composites

Technologies and materials processing

Primarily interested in fine inorganic problematic materials

Incinerator bottom ash:

lightweight aggregate alkali activated cements

sintered ceramic productsAir pollution control (APC) residues:

stabilisation/solidification glass, ceramics, glass ceramics, geopolymers

Sewage sludge ash:

alkali activation/pozzolanic propertiesphosphate extraction/phosphoric acid production

Spent bleaching earth:

stabilisation/solidificationnovel composites

Mixed colour glass:

lightweight aggregateQuarry fines:

cat litterSilt from aggregate washing:

aggregate, flowable fill/CLSMPulverised fuel ash:

sintered ceramic productslightweight aggregate

Oil drill cuttings:

sandcrete blocks, geopolymers, sintered ceramicsScallop shells:

lime cementsMetal finishing wastes

sintered ceramics

Types of Wastes

Increasing costs of disposal/management as driver for innovation

Silt from aggregate washing plants

Aggregate washing plant

Aggregate washing

The problemAggregate washing plants produce up to 80 tonnes per hour of waste siltEstimate ~ 400,000 tonnes of waste silt produced per year from aggregate washingSilt management is having a major impact on plant operating costs

Cost implicationsUp to £24 per tonne for landfill disposal Estimated at ~ £1.0 M per annum per plantTotal cost to the aggregate recycling industry ~ £10M per annumThis is only likely to increase!

Problem = Opportunity Need to develop a sustainable solution –

sustainable products

Commercial and environmental drivers in place

Silt from aggregate washing

How to avoid landfill disposal of silt?

Manufacture of aggregate: Portland cement/polymer system usinga mixing/extrusion/pelletising technology

Flowable fill: Free flowing, setting time between 24 and 48 hours, (CLSM)

compressive strength 1-2 MPa but < 4 MPa

Both options are potential business opportunities

Air pollution control (APC) residues

Municipal solid waste management

UK Energy from Waste facilities:

1) Lerwick 2) Dundee

3) Billingham 4) Bolton

5) Huddersfield 6) Grimsby

7) Sheffield 8) Stoke

9) Nottingham 10) Wolverhampton

11) Dudley 12) Tyseley 13) Coventry

14) Swansea 15) Edmonton

16) Lewisham 17) Chineham 18) Marchwood

19) Portsmouth

UK Energy from waste plants

http://upload.wikimedia.org/wikipedia/commons/9/9f/SELCHP.jpg

Air Pollution Control (APC) residues

APC resides -

Hazardous waste from cleaning gaseous emissions

European Waste Catalogue -

19 01 07* Solid wastes from gas treatment

Mixture of lime, fly ash and activated carbonlime to neutralise any excess acidfinely divided activated carbon to remove heavy metals and dioxins

Fine particles removed by high efficiency filters

Hazardous waste -

primarily due to high alkalinity

UK currently generates ~160,000 tonnes per year and increasing

Moderador


APC residues are the fine powdered waste generated from air pollution abatement systems in EfW plants processing municipal solid waste. It is a mixture of fly ash, lime and carbon. Lime is used to neutralise any excess acid and carbon to remove heavy metals. APC residues are classified as hazardous waste with an absolute entry in the European Waste Catalogue (EWC 19 01 07*). The incineration of 1 tonne of municipal solid waste typically produces about 30 kg of APC residues.

Aqua regia total metals/soluble ions

mg/kg

Leachable metal ions at L/S10

mg/kg

Hazardous landfill WAC

mg/kgAlCaCdCoCrCuFeKNaNiPbSiTiZnCl-

10,000-24,000250,000-350,000

100-1509-14

12-200350-600

3,000-5,2009,000-24,00013,500-20,500

15-352,500-3,500

Nd900-4,000

4,000-8,500160,000

-----

1.3 –

3---

0.2 –

45300 –

700--

40 –

85140,000 –

170,000

-----

100---

4050--

20025,000

Composition and leaching of APC residues

BS EN 12457-3

APC residue treatment and disposal

Heavy metals, high alkalinity, high soluble salt content, leachable chloride

UK options for APC residues:

–

Hazardous waste landfill -

fails WAC due to excessive Cl-

leaching–

Long-term storage in salt mines -

limited capacity

–

Chemical treatment -

mixing/reacting with waste acid–

Solidification/stabilisation

–

Thermal treatment -

vitrification

DC plasma technology supplied by Tetronics

Moderador


The main issues with APC residues are: Volatile heavy metals, High alkalinity (> pH 12) due to the use of excess lime, Soluble chloride and sulphate salts, Sometime they might also have organic contaminants like dioxins and furans Current management options for APC residues are: Hazardous waste landfill Long-term storage in salt mines Chemical treatment Solidification/stabilisation Thermal vitrification The main waste management option for APC residues is disposal in hazardous waste landfill, which is being challenged by both regulatory and political pressures in the UK.

DC plasma treatment of APC residues

PLASMA ZONE

> 10,000 K

High Temperature Destruction of Organics

Metallic Phase

Recovery of Metal Value

High Intensity UV

Catalysis of Photo-Chemical Reaction

Environmentally Stable Slag

Repository for Heavy Metals

Furnace Off Gas

Combustible Gases and Volatile Species

PLASMA ZONE

> 10,000 K

High Temperature Destruction of Organics

Metallic Phase

Recovery of Metal Value

High Intensity UV

Catalysis of Photo-Chemical Reaction

Environmentally Stable Slag

Repository for Heavy Metals

Furnace Off Gas

Combustible Gases and Volatile Species

DC plasma furnace

Feed to plasma (wt.%): 69.8% APC residues, 21.9% SiO2

, 8.3% Al2

O3

Blend melted at~1500 -

1600°C

Re-use of plasma treated APC residues

cms

APC residues

plasma

process

APC residue glass

10 20 30 40 50 60In

tens

ity (a

.u.)

2 (deg.)

XRD -

APC residue glass

10 20 30 40 50 60

A

A

C CD

B

A

A

D

A

F

AA

G

D EHA

D

H

D

F A

D

C

H

Inte

nsity

(a.u

.)

2 (deg.)

AB

CEA DDD

A - CaClOHB - CaSO4C - K2SD - CaCO3E - SiO2F - NaClG - Ca(OH)2H - KCl

XRD -

APC residue

DC plasma treatment: viable treatment for APC residues APC residue derived glass: inert waste

Possible reuse applications of APC residue glass include:Unbound aggregateAggregate in concreteSand blastingDecorative cement bonded glass concrete productsPolymer/resin bonded glass products Decorative sintered tiles

Sintered products such as pavers, slips, bricks and tilesGlass-ceramics Cast glassAPC residue glass-geopolymer composites

Possible reuse applications of APC residue glass

APC residue

glass

Crushed<250μm

bottle glass,glass sand,

other wastes

Mixer

~ 5% clayand water

Uni-axial pressing

Sintered Product

The envisaged products are slips, tiles and pavers60,000 tonne per annum plant

APC residue glass supplied as fritEasier to process to < 250μmBottle glass purchased as EcoSand

APC residue glass sintered products

Standard ceramic processing technology

Uniaxial pressing at 250 kgcm-3

Sintering: ramp rate of 10°Cmin-1, 1 hour dwell, temperatures 600 to 1100°C

Sintered APC residue derived glass tiles

100APC and 50:50 APC:CG –

various coloured products

600 700 800 900 1000 1100 1200

1.6

1.8

2

2.2

2.4

2.6

Monoporosa tilesFloor tilesPorcelain tilesCullett glass - 100 wt%APC derived and cullett glass : 50 + 50 wt%APC derived glass : 100 wt%

Bul

k de

nsity

(g/c

m3 )

Temperature oC

Density -

sintering temperature data

600 700 800 900 1000 1100 12000

5

10

15

20 Monoporosa tilesFloor tilesPorcelain tiles

APC derived glass : 100 wt%APC derived and cullett glass : 50 + 50 wt%Cullett glass - 100 wt%

Temperature oC

Wat

er a

bsor

ptio

n (%

)

Water absorption -

sintering temperature data

Geopolymers from APC residue glass

Parameters optimised: •

Si/Al ratio

•

S/L ratio•

Type and concentration of activating solution

•

Curing temperature and conditions•

Particle size distribution

Geopolymers

Aluminosilicates reacted with alkali hydroxide or alkali silicate solutionSiO4

and AlO4

tetrahedra linked by shared oxygen atomsLow-carbon sustainable materials

Materials

•

APC residue plasma derived glass TEMA milled for 2 minutes•

Sodium hydroxide –

alkali source

•

Sodium silicate solution –

silicate source

TEMA milled APC residue glass powder Particle size distribution data

Moderador


For the preparation of geopolymers, plasma vitrified glass was further milled to form a fine powder using a dry milling process (TEMA mill, TEMA Machinery Ltd). A SEM image of plasma vitrified glass powder is shown in the Figure. Both small and relatively large (~100 μm) glass particles can be seen, indicating a broad particle size distribution. For all experiments, the activating solution was made up from sodium silicate solution (VWR) and sodium hydroxide pellets (Fisher Chemicals) dissolved in distilled water.

Compressive strength data

0

20

40

60

80

100

120

140

2 4 6 8 10 12

[NaOH] in the activating solution (molar concentration)

Com

pres

sive

Str

engt

h (M

Pa)

7 Days curing

28 days curing

Moderador


The compressive strength values of plasma vitrified glass geopolymers obtained using different NaOH concentrations in the activating solution at different curing times. This shows that the compressive strengths of APC glass derived geopolymers increased with increasing concentration of NaOH reaching a maximum value at 6M. Compressive strength was further developed after curing for 28 days reaching values of 90-110 MPa; this was expected as geopolymerisation continues after setting has occurred. The dissolution of the aluminosilicate species increases with increasing NaOH concentration in the activating solution. This causes an increase in the amount of monomers available for geopolymerisation, leading to a higher degree of geopolymerisation and higher compressive strength of the final material. A decrease in compressive strength was observed in samples prepared with NaOH concentrations greater than 10M. This is in agreement with previous research which showed that excessive NaOH can adversely affect the geopolymerisation process. Very high compressive strengths and high densities have previously been attributed to the presence of Ca in geopolymer systems.

Comparison of microstructures

[NaOH] = 4 [NaOH] = 6

[NaOH] = 10

Reduced size of residual APC residue glass particles with increasing NaOH concentration

Geopolymer -

glass composites

Moderador


Micrographs of selected geopolymer samples prepared after compressive strength tests are shown in the Figures All images show a heterogeneous microstructure containing un-reacted APC glass particles of various sizes and shapes, surrounded by a geopolymer binder phase. This suggests that small APC glass particles react completely while the larger particles are only partially reacted during geopolymerisation. The amount of unreacted material present is related to the NaOH concentration in the activating solution. It can be seen that the sample prepared with 4M NaOH contained larger particles than the samples prepared with 6M or 10M NaOH in the activating solution since the dissolution of the solid aluminosilicate APC residue glass powder increases with increasing NaOH concentration in the activating solution. Furthermore, the SEM images reveal that geopolymer samples prepared with 6M NaOH and above had very low porosity.

Geopolymer prepared with [NaOH] = 6

APC residue glass geopolymer composites

Amorphous High compressive strength ~ 110 MPaDensity = 2070 Kg/m3

Water absorption = 11%

XRD analysis of optimum APC glass geopolymer

5 10 15 20 25 30 35 40 45 50 55 60Angle 2Θ (deg)

Inte

nsity

(a.u

.)

Crack propagation around APC glass particles and through geopolymer phase

APC residues glass particles

geopolymer

Moderador


Samples prepared with 6M NaOH had the highest compressive strengths (~110 MPa) and this is considered to be the optimum mix for plasma derived glass geopolymers. These geopolymer samples had been further characterised and they had a density of 2070 kg/m3 and a water absorption of 11% The XRD analysis demonstrated that the optimum geopolymer samples were completely amorphous, as indicated by the high background in the XRD data around 30o 2θ, which is in accordance with previous research. The absence of crystalline peaks does not preclude the possibility of amorphous C-S-H or calcium hydroxide forming due to the high amount of calcium in the plasma vitrified glass.

Sewage sludge ash

1. Beckton: East London2. Crossness: East London3. Roundhill: Stourbridge4. Coleshill: Birmingham5. Leeds6. Sheffield7. Huddersfield8.

Bradford9.

Widnes10. Belfast

UK sewage sludge incinerators

Sewage sludge incinerators

Sewage sludge incineration plant

~100,000 tonnes of ISSA produced per year in the UK

Beneficial reuse applications for ISSA

1. Characterisation of ISSA from UK plants

2.

Evaluation of pozzolanic activity by different methodsStrength activity index testFrattini testSaturated lime test

3.

Development of phosphate extraction by acid leachingOptimised process conditions

(reaction time, acid concentration, L/S ratio) High value phosphoric acid productPozzolanic activity of the acid treated residue

20µm

1000µm 200µm 60µm

Blackburn Meadows SEM with EDS

Sewage sludge ash samples

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

2θ degrees

Cou

nts

(offs

et fo

r cla

rity)

Q

Q

W

H

W

H HH

W

HHH

WQ

W Q QQW

QW

Q Q QQQ

H

Q

WXN

Beck

UU

Knos

Esh

CVI

BBM

Q - Quartz SiO2 - various formsH - Haematite Fe2O3 - various formsW - Whitlockite Ca3(PO4)2 - various forms

UK ISSA typically contains 14 to 18% by weight P2

O5

0

10

20

30

40

50

60

70

80

90

100

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

H2SO4 concentration (Mol/L)

% to

tal e

lem

ent e

xtra

cted

ZnFeMgCaAlP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25

L/S ratio (ml/g)

% to

tal e

lem

ent e

xtra

ctio

n ZnFeMgCaAlP

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700

Reaction time (mins)

% to

tal e

lem

ent e

xtra

cted

Zn

FeMg

CaAl

P

Extraction efficiency of P, Zn and major cations from ISSA

with reaction time (0.5mol.l-1

H2

SO4

at a L/S ratio of 20).

Phosphorus extraction experiments

Effect of H2

SO4

concentration on P extraction (reaction time 120 mins, L/S ratio 20).

Effect of L/S ratio on average extraction efficiency of P.

0

10

20

30

40

50

60

70

80

90

100

BBM Esh CVI Knos UU Beck XN

% T

otal

Pundissolved Pextracted P

P extraction efficiencies from other ISSA samples using the optimised process.

ISSA

H2

SO4

Electrical energy

Reaction chamber

2hrs mixing

drying millingRe-use as a

cement replacement

material

vacuum filtration

Electrical energy

cation exchange

HCl

evaporation

Electrical energy or low grade heat

Electrical energy

Electrical energy or low grade heat

~85% H3

PO4

solids

liquids

Phosphoric acid production process

Portland cement and alternative low carbon cement

systems

Sintering temperature of 1450ºCDecomposition of limestone (CaCO3

) with release of CO2

Portland cement manufacture

Cement kilns

Portland cement

Cement is the most manufactured material;Hugely important for modern society;Associated with significant adverse environmental effects:

CO2

emitted in huge quantities;Kiln relies on fossil fuels;High embodied energy due to heating and grinding.

Significant drivers for change.

Options for CO2

reduction:Substitution of fossil fuels;Use of alternative clinker raw materials;Replacement of clinker by secondary cement materials;

Calcined claysDevelopment alternative binders/cements.

Problems and solutions

Novel cement system based on MgO and mineral additives

Formulation effectively locks CO2

into the cement

Manufacturing process causes minimal CO2

emissions

Low temperature, chemical process, non-carbonate raw materials

Hardens by absorbing atmospheric CO2

Potential to form 'carbon negative' construction products.

Novacem -

an Imperial spin-out

Novacem LimitedThe Incubator, Bessemer Building

Imperial College, South KensingtonLondon SW7 2AZ, UK

[email protected]

Conclusions

Environmental issues are now driving materials development;

Economic/business factors key for innovation and change;

Time of tremendous opportunities;

Key role of materials science and processing;

Move towards a significant industrial sector based on materials cycles.

Research needed in the key areas of RESOURCE EFFICIENCY AND SUSTAINABLE MATERIALS

Acknowledgements

For more information please contact: [email protected]

PhD students and Post Doctoral researchers: Amutha

Deveraj, Nikolaos

Vlasopoulos, Marta Pellizon

Birelli, Nicola Bianco, Rosie Greaves Shane Donatello, Abdelhamid

Beshara, Babagana

Mohammed, Ioanna

Kourti, Carsten

Kunzel, Tingting

Zhang, Fei

Zhang, Christos Lampris, Christine Dimech, Vanessa Adell, Richard Lupo

Research collaborators: Aldo Boccaccini, Luc Vandeperre, Mark Tyrer, Julia Stegemann, Chi Poon, David Wilson, Bill Townend, Xuichen

Qiao, Geoff Fowler

Research Sponsors: Technology Strategy Board, EPSRC, Defra-

BREW, Egyptian Government, PTDF Nigeria

Industrial Sponsors: Tetronics

Ltd, Rio Tinto Minerals, Laing O’Rourke, Duo, Walsh, Veolia Environmental, SELCHP, Claylite

Aggregates, Akristos, Bob Martin, Ballast Phoenix, Grundon

Waste Management, UKQAA, BCA, Elkem, NISP, WRAP, Imperial Innovations

Ana Guerrero: Eduardo Torroja

Institute for Construction Science (CSIC)Jose Monzo

Balbuena: Universidad Politécnica

de Valencia

role of materials development in resource efficiencypage 1 imperial college london chris cheeseman...

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