cementos belíticos y sulfobelíticos - · pdf filecementos belíticos y...

Miguel A. G. Aranda

Departamento de Química Inorgánica, Universidad de Málaga

[email protected]

http://webpersonal.uma.es/~mag-aranda/

Cementos

belíticos

y sulfobelíticosa way for reducing CO2

emissions

Monday, 13 September 2010

Outline Outline

1. Introduction to cement industry environmental problem

2. Searching for sustainable materials and processes

6. Conclusions

4. Laboratory active belite cements

5. Laboratory active belite sulfoaluminate cements

3. Methodology (mainly at Universidad de Málaga)

Industrial production of Ordinary Portland Cement

Dry processDry processQuarry

Kiln

1450ºC

Raw materials:Limestone (Ca)Clays (Al, Si)FeldsparsFe2 O3 (iron ore / rust)

Rawmix mill

Cement mill(s)

Gypsum and additions

Green house gases: CO2

, etc.

CaCO3 CaO

+ CO2

0.54 Tons / ton of clinker

The overall CO2

emissions of cementindustry (~

0.98 T) are

6% of all

anthropogenic carbon dioxide release

Cement industry contributes to the global warming of the planet in

4%

Other emissions: ~

0.34 T from fuel burning

~

0.10 T from electricity

T=1450ºC

OPC

Outline Outline



6. Conclusions




2.1. Addition of mineralizers and/or fluxes, to enhance burnability and/or decrease the firing temperature.

2.2. Partial replacement of clinker by an active hydraulic compound (blended cements).

2.3. The use of (slightly) different mineralogical systems to decrease the burning temperature and/or to obtain highly reactive constituents.

2. Searching for sustainable materials and 2. Searching for sustainable materials and processes for reducing COprocesses for reducing CO

22

emissionsemissions

2.1. 2.1. MineralizersMineralizers / fluxes (as an example)/ fluxes (as an example)

Sulfates, chlorides, carbonates, phosphates, fluorides, fluorosilicates etc…

Phosphogypsum (PG) as raw material: CaSO4 ·2H2 O + Na2 SiF6

10% PG

1200ºC

0.4 % CaOfree Alite & belite

low crystal sizes

liquid phase: porosity grinding

High mechanical strength 28 days Valorization of waste materials

Kacimi

et al., J. Hazardous

Mat. 2006

2.2. Partial replacement of clinker by 2.2. Partial replacement of clinker by an active hydraulic compoundan active hydraulic compound

As an example: Pozzolanic

based cements

Pozzolanic

reactionProduct of OPC hydration

The hydration of alite

with silica fume (S) gives 1.76 times much C-S-H / C3

S consumed

Up to a reduction of 43%

of CO2

emitted from raw materials (compared to pure C3

S) could be obtained.

Gartner, Cem. Concr. Res. 2004

Alkaline activation of fly ashes

Alkaline activation of slags

They will be treated in other lectures

(among other systems)

2.3. Alternative mineralogical systems2.3. Alternative mineralogical systems

CO2

emissions relationship between

OPC(ordinary Portland cement;

based on alite, and others)&BSA(belite sulfoaluminate

cements;

based on belite, C4

A3

$, and others)

1.- ‘Active’ belite Portland cements:To decrease the LSF from 98 to 71 leads to a

11% reduction of CO2

emissions (less calcite as raw material). Furthermore, extra reduction (close to 3%) may be attained from burning at lower temperatures (1350 ºC instead of 1450 ºC)

since less fuel is needed.

2.- ‘Active’ iron-rich belite sulfoaluminate cements:Plus the above described savings ~ 10% from substituting alite

by belite (smaller LSF)

~

5 % from burning the clinker at 1300 ºC (fuel saving) ~ 15%

from partial substitution of CaCO3

by CaSO4

.Therefore, more than 30% of CO2 emissions savings can be obtained.

C2

S C4

A3

S C4

AF



Problem:Low early mechanical strengths

a) High-belite cements:

LSF: higher C2

S less C3

S b) Sulfoaluminate based cements: C4

A3

S

Burning at 1250 ºC

ActivationActivation

of belite clinkers of belite clinkers Higher mechanical strength at early agesHigher mechanical strength at early ages

Quenching. Chemistry stabilisation.

-forms stabilisation by oxides such as Na2 O , SO3 , BaO and K2 O.

Hydraulicallynon-active.

Hydraulically very active.

Ordinary Portland clinker component.Mechanical strength at later ages.

'

L '

H

1425ºC1160ºC

780-860ºC

690ºC< 50

0ºC

'

L '

H

1425ºC1160ºC

780-860ºC

690ºC< 50

0ºC

High-belite cements - Quenching

LSF: higher C2

S less C3

S

High-belite cements

Decrease

CO2

emissionsin the decomposition of calcite

(8%).

The optimum clinkerizationtemperature is roughly 100 ºC lower

Belite based concretes are moredurable

.

Wolter, Cement

International 2005

Quenching

mechanical strength3000 K/min vs. 100 K/min

in belite cements

(at 28 days)

Belite sulfoaluminate cements # 1

Raw materialsCalcite (Ca)bauxite (Al)Fluidized bed combustion

(FBC) (Ca, Si, Al & S)Fly ash (Al, Si)Red mud (Al, Si & Fe)

Potential mineralogical clinker compositions (main phases)

CSA cements

Flue Gas Desulfuration (FGD) gypsum

Thermal treatment: 2h @ 1150-1300ºC

Advantages Easier to grind (

liquid phase

porosity)

synthesis temperature

CO2 emissions

Used (valorization) of waste materials

porosity on hydrated samples

durability

Valenti et al., W3-11.2, 12th ICCC, Montreal 2007Canonico et al., W3-11.4, 12th ICCC, Montreal 2007

M7

M8


Clinkering temperature = 1300ºC

Li et al., TH3-15.3, 12th ICCC, Montreal 2007

1/3

Li et al., TH3-15.3, 12th ICCC, Montreal 2007

’-forms’-forms

’-forms

2/3


Outline Outline



6. Conclusions




C3S

C3S

C3S C

3S

C3SC2S

C2S

C2S

C2S

C2S

C3A

C4A

F

C4A

FC

3S

NK

SN

KS

NK

SN

KS

C

8.5 9 9.5 10 2º 10.5

I (u.

a.)

C3S

C3S

C3S C

3S

C3SC2S

C2S

C2S

C2S

C2S

C3A

C4A

F

C4A

FC

3S

NK

SN

KS

NK

SN

KS

C

8.5 9 9.5 10 2º 10.5

I (u.

a.)

C3S

C3S

C3S C

3S

C3SC2S

C2S

C2S

C2S

C2S

C3A

C4A

F

C4A

FC

3S

NK

SN

KS

NK

SN

KS

C

8.5 9 9.5 10 2º 10.5

I (u.

a.)

Synchrotron powder diffraction data,=0.44 Å

We are using a similar approach (but with synchrotron and CuK1,2 radiations)

Transm

ission

Convert the divergent X-ray beam from a tube in line focus position to an intense beam

that focuses onto the goniometer

circle.

Sample

X-Rays tube

Convergent beam

Goniometercircle

Mirror

FocusDivergent incident beam

Laboratory X-ray Powder data collectionIn-situ hydration

Application laboratory of PANalytical

(Almelo, The Netherlands)

=1.5418 ÅFlat sample

Synchrotron X-ray Powder data collectionIn-situ hydration

W/C= 0.5

Slits Sample

X-Rays

~2 mm

Transm

ission

Cement Water

Image plate detector: two data collection strategies

BM08 beam line @ ESRF=0.6888 Å

Debye Scherrer

configurationFlat sample

Translating mode

2D single pattern

Clinkering process for belite clinkers is not well knownPolymorphic transformations at high temperatureLiquid appearance temperature(s)Influence of minor elements in these reactions

Why an in-situ study?

Selected compositions

1.00.50.5Bel_10S05K05N

1.0-1.0Bel_10S10K

-0.50.5Bel_05K05N

-1.5-Bel_15N

--1.0Bel_10K

---B_ref

SO3/%Na2O/%K2O/%sample

1.00.50.5Bel_10S05K05Na

1.0-1.0Bel_10S10K

-0.50.5Bel_05K05Na

-1.5-Bel_15Na

--1.0Bel_10K

---B_ref


1.00.50.5Bel_10S05K05N

1.0-1.0Bel_10S10K

-0.50.5Bel_05K05N

-1.5-Bel_15N

--1.0Bel_10K

---B_ref


1.00.50.5Bel_10S05K05Na

1.0-1.0Bel_10S10K

-0.50.5Bel_05K05Na

-1.5-Bel_15Na

--1.0Bel_10K

---B_ref


Clinkerization process for an ordinary Portland Clinker

700-900ºC Decarbonation (CO2 )

900-1300ºC free lime, Al & Fe rich phases and silicates

1300-1450ºC liquid phase + silicates

Quenching Phase stabilisation + subcooled liquid

CO 2

CaCO 3

-Cuarzo

Arcill a

-cuarzo

CaOAlitaC 3 S

BelitaC 2 S

Fe 2 O 3

C 12 A 7C 4 AF líquido C 4 AF

C 12 A 7

140012001000 1000800600 T (ºC)

Pro

porc

ión

de C

ompu

esto

s

CO 2

CaCO 3

-Cuarzo

Arcill a

-cuarzo

CaOAlitaC 3 S

BelitaC 2 S

Fe 2 O 3

C 12 A 7C 4 AF líquido C 4 AF

C 12 A 7

140012001000 1000800600

CO 2

CaCO 3

-Quartz

Clays

-cuarzo

CaOAlitaC 3 S

BelitaC 2 S

Fe 2 O 3

C 12 A 7C 4 AF liquid C 4 AF

C 3 A

140012001000 1100800600 RT

Por

tions

by

wei

ght

C3 AC4 AF

C2 S

C3 S

Temperature (ºC) cooling

Thermo-diffractometric

data collection

Pt capillaryØ=0.6 mm

Metallic sample holderMgO refractory

capillary

Refractory ceramic adhesive

Raw mix inside

Data collection

ESRF (Grenoble)ID31 diffractometer=0.3007 ÅDebye Scherrer configurationCapillaries were spunAngular range 2.5-30o (in 2) 15 minutes per run3 runs for a single pattern

Real temperature was checked by Pt peak positions

Samples were heated from 900 to 1450ºC

Halogens lamps

Ceramic holder

0

10

20

30

40

50

60

70

80

wt%

900 1000 1100 1200 1300 1400

T / ºC

0

10

20

30

40

50

60

70

80

wt%

900 1000 1100 1200 1300 1400

T / ºC

Reference

belite clinker

(B_ref) on

heating

1240ºC

Free lime (CaO

) 9.6(2)wt%

(1) Primary formation of C4

AF ( )

Free lime (CaO

) 4.2(1)wt%(3) Formation of C3

A ( )(4) Crystal size growth of C4

AF ( )

1055ºC

C

CaOCaO

3C S

AFC4AF

-C2S

’H-C2S ’L-C2S

C A3

Liquid phase

C

CaOCaO

3C S

AFC4AF

-C2S

’H-C2S ’L-C2S

C A3

Liquid phase

0

10

20

30

40

50

60

70

80

wt%

900 1000 1100 1200 1300 1400

T / ºC

0

10

20

30

40

50

60

70

80

wt%

900 1000 1100 1200 1300 1400

T / ºC

1350ºC

(7)

’H

-C2

S -C2

S( )

C3

S ( )

1300ºC

C

CaOCaO

3C S

AFC4AF

-C2S

’H-C2S ’L-C2S

C A3

Liquid phase

C

CaOCaO

3C S

AFC4AF

-C2S

’H-C2S ’L-C2S

C A3

Liquid phase

B_ref on heating (continuing) (5) Melting

of

C3

A ( ) & C4

AF ( )(6)

’H

-C2

S( ) + CaO

C3

S ( )

Free lime (CaO

) 0.0wt%

Liquid phase ( )

Liquid

phase

(B_ref) on

heating

Nominal

compositionC4AF/% C3A/%

16 81180ºC 17.7(3) 6.2(2)

Melting

Formation

Formation/sinterization

6.30 6.35 6.40 6.45 6.50

2/º

920 ºC

1055 ºC

1180 ºC

1300 ºCCC44 AFAF

CC33 AA

Active belite clinker 1.0% K2

O

(B_10K) on cooling

10.0--6.5(3)3.5(1)9.5(2)10.3(2)60.2(1)--1055 ºC

10.5--6.2(3)3.3(2)9.4(2)--70.6(1)--1175 ºC

11.1--5.6(3)3.3(2)9.3(2)--70.7(2)--1238 ºC

20.0------7.6(2)----72.4(1)1310 ºC

20.0----7.1(2)----72.9(1)1308 ºC

20.0------7.3(2)----72.7(1)1440 ºC

--4.6(1)14.0(2)6.0(2)----75.4(1)--1200 ºC

Liquid phaseCaOC4AFC3AC3S'L-C2S'H-C2S-C2SB_1.0K

10.0--6.5(3)3.5(1)9.5(2)10.3(2)60.2(1)--1055 ºC

10.5--6.2(3)3.3(2)9.4(2)--70.6(1)--1175 ºC

11.1--5.6(3)3.3(2)9.3(2)--70.7(2)--1238 ºC

20.0------7.6(2)----72.4(1)1310 ºC

20.0----7.1(2)----72.9(1)1308 ºC

20.0------7.3(2)----72.7(1)1440 ºC

--4.6(1)14.0(2)6.0(2)----75.4(1)--1200 ºC

Liquid phaseCaOC4AFC3AC3S'L-C2S'H-C2S-C2SB_1.0K

5.0 5.5 6.0 6.5 7.0

1400ºC

1350ºC

1300ºC

1250ºC1200ºC

1100ºC

RT

2/º

cool

ing

5.0 5.5 6.0 6.5 7.0

1400ºC

1350ºC

1300ºC

1250ºC1200ºC

1100ºC

RT

2/º

cool

ing

We have carried out a similar in situ type of study for belite sulfoaluminate

clinkering,

to be reported very soon.

Outline Outline



6. Conclusions




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