Environmental Performances of Bricks made from Stainless Steel Slag: A Life Cycle Assessment Approach - Andrea Di Maria

1. Environmental Performances of Bricks
made from Stainless Steel Slag:
A Life Cycle Assessment Approach
Andrea Di Maria 1

2. Outlines
Ø Bricks from Stainless Steel Slag (SSS)
• Stainless steel slag
• Unfired Bricks from SSS
Ø Environmental evaluation: Life Cycle Assessment (LCA)
• Methodology overview
• Results of assessment for SSS bricks
Ø Comparison of results with previous LCA
Ø Conclusions
2

3. The StainlessSteelSlag (SSS) bricks
Ø Masonry and facade bricks developed from Stainless Steel Slag
(SSS)
3
SSS bricks
Stainless Steel Slag
Chemical
treatments
Technical aspect
Is it possible to make bricks from slags which fulfil the current
normative requirements in terms of shear stress and bearing
capacity?
Environmental Aspect
Looking at the whole life cycle, what are the environmental benefits
of using these new bricks compared to traditional bricks?
Economic aspect
What is the economic potential for such technologies and their
strong and weak points in a view of a possible market introduction?

4. Stainless Steel Slag (SSS)
• Stainless steel production by-products
• 300 Kg of SSS each tonne of steel produced
• 8,7 Mtons of SSS produced in 2011
4
Industrial
Product
Industrial
By-product
SS Slag
Stainless Steel
The Stainless Steel Slag (SSS)

5. Stainless Steel Slag (SSS)
• SSS contains high quality oxides (CaO,SiO2,Al2O3,MgO)
• Hazardous compounds (Cr, Pb, Ni, Cd ). Borates or cement
addition to stabilised the slag
Landfilling
Recycling
Stabilization
required!
Aggregates and
filling material in
road construction
Low value
application
(downcycling)
The Stainless Steel Slag (SSS)

6. The StainlessSteelSlag (SSS) bricks
• Alternative brick production using Industrial by-products (Fly
ashes from MSW incineration, Granulated blast furnace slag, etc.)
• Findings to date demonstrated that unfired bricks can be
used as base for construction materials
reactor
chamber
Carbonation
Alkali activation
Perforated
SSS bricks
Solid
SSS bricks
Aerated
SSS bricks
Ø Unfired Bricks
Stainless
Steel
Slag

7. The StainlessSteelSlag (SSS) bricks
Perforated
SSS bricks
Solid
SSS bricks
Aerated
SSS bricks
Ø Carbonation
• Method of carbon capture that accelerates the natural weathering of
calcium, magnesium and silicon oxides, allowing them to react with CO2
to form stable carbonate
퐶푎 (푂퐻)↓2 + 퐶푂↓2 =퐶푎 퐶푂↓3 +
퐻↓2 푂 Oxides Carbonates (Solid)
Ø Alkali Activation
• Chemical process that transforms glassy structures into compact and
well cemented composites, through chemical activation with alkali
compounds

8. RESEARCH QUESTION
Ø Looking at the whole life cycle, what are the environmental
benefits of using these new bricks compared to traditional
bricks?
Life Cycle Assessment (LCA)
Methodology allowing to assess environmental impacts
associated with all the stages of a product's life from-cradle-to-grave
8
The StainlessSteelSlag (SSS) bricks

9. 9
Goal
and
Scope
Inventory
Analysis
Impact
Assessment
Interpretation
The LCA framework
• Functional unit
• System boundaries
• Data collection
• Data treatment
• Calculation method
• Results analysis
Life Cycle Assessment

10. 10
Goal
and
Scope
framework
Inventory
Analysis
LCA The Impact
Assessment • Functional unit
• System boundaries
• Data collection
• Data treatment
Life Cycle Assessment

11. Comparison
S-2 bricks to traditional bricks with similar properties (substitutes) that
are already available in European markets
§ Perforated and solid S-2 bricks→ fired clay bricks
§ Aerated S-2 brick → Autoclaved brick (ytong)
Functional unit
Impacts related to the production of 1m³ of bricks
Avoided impact
It refers to the impact of virgin material production that is avoided by the
use of recycled material. In LCA it accounts as a value to be subtracted
to the total impact (negative value)
11
Life Cycle Assessment

12. 12
Systems analysis

13. SSS Bricks vs Traditional bricks
13
Systems analysis

14. 14
Goal
and
Scope
framework Inventory
Analysis
LCA The Impact
Assessment • Calculation method
• Results analysis
Impact Assessment

15. 15
Raw Materials
Land use
CO2
VOC
P
SO2
NOx
CFC
PAH
DDT
Calculation methodology
Ozone depletion
Human toxicity
Radiation
Ozoneformation
Particules form.
Climate change
Terr. ecotox
Terr. acidif.
Agr. land occ.
Urban. land occ.
Nat. land transf
Marine ecotox.
Marine eutr.
Freshwater eutr.
Freshw. Ecotox.
Fossil fuel cons
Mineral cons.
Water cons.
Damage
Damage
Damage
Human Health
(Daily)
Ecosystems
(Species yr.)
Resources
(Cost)
Single
Score
Substances Midpoints Endpoints
Uncertainty
ReCiPe
Impact Assessment

16. Impact Assessment
Results(1): Single Score (impact categories)
16
60
50
40
30
20
10
0
-­‐10
-­‐20
-­‐30
-­‐40
Solid AA bricks
Perforated bricks CC
Perforatef bricks R
Clay brick
Pt
Climate
change
Fossil
deple;on
Par;culate
ma>er
forma;on
Metal
deple;on
Human
toxicity
others

17. Results(1): Single Score (processes contribution)
100 100%
17
60
40
20
0
-20
-40
80
60
40
20
0
-20
-40
-60
1.76%
Total impact
-61.71%
Clay
bricks
Perforated
bricks R
Solid AA
bricks
Percentage
Perforated
bricks CC
Pt
31.39%
Clay bricks
Perforated
bricks R
Disposal landfill (0.42)
Disposal recycle (0.24)
Landfill - avoided impact (-16.58)
Steam (0.02)
Sand mining (0.41)
Alkali production (34.24)
Disposal landfill (0.41)
Disposal recycle (0.24)
Landfill - avoided impact (-42.95)
CO2 production (10.13)
CO2 uptake (-4.69)
Perforated
Solid AA bricks CC
bricks
Disposal landfill (0.41)
Disposal recycle (0.24)
Landfill - avoided impact (-42.96)
Electricity (32.92)
CO2 production (10.13)
CO2 uptake (-4.69)
Disposal landfill (0.61)
Disposal recycle (0.35)
Process materials (2.44)
Raw materials (3.76)
Engergy consumption (29.54)
Direct emission (23.04)
Impact Assessment

18. 18
Impact Assessment
Results(2): Single Score (impact categories)
12
10
8
6
4
2
0
ytong
Aerated
AA
bricks
Pt
Climate
change
Fossil
deple;on
Human
toxicity
Metal
deple;on
Others

19. 19
Results(2): Single Score (processes contribution)
11.95 11.94
Aerated AA bricks
20
15
10
5
0
-5
-10
Pt
Disposal landfill (0.95%)
Disposal recycle (1.22%)
Electricity (63.95%)
Lime production (26.77%)
Cement production (6.31%)
Sand mining (0.74%)
Ytong
Disposal landfill (1.85%)
Disposal recycle (1.08%)
Landfill - avoided impact (-65.25%)
Steam production (0.18%)
Alkali production (160.56%)
Sand mining (1.30%)
Aerated AA bricks Ytong
22
20
18
16
14
12
10
8
6
4
2
0
Pt
Total impact
Impact Assessment

20. 20
Results(2): Single Score (processes contribution)
11.95 11.94
Aerated AA bricks
20
15
10
5
0
-5
-10
Pt
Disposal landfill (0.95%)
Disposal recycle (1.22%)
Electricity (63.95%)
Lime production (26.77%)
Cement production (6.31%)
Sand mining (0.74%)
Ytong
Disposal landfill (1.85%)
Disposal recycle (1.08%)
Landfill - avoided impact (-65.25%)
Steam production (0.18%)
Alkali production (160.56%)
Sand mining (1.30%)
Aerated AA bricks Ytong
22
20
18
16
14
12
10
8
6
4
2
0
Pt
Total impact
Impact Assessment

21. Comparison with similar LCA
Ø Saving energy
From (Koroneos et al. 2007)*:
Emissions of CO2, SO2 and NOx , released during the baking stage, highly contribute to
the total environmental impacts of clay brick production, and actions to reduce these
emissions would affect significantly the final score
45000
40000
35000
30000
25000
20000
15000
10000
5000
0
Raw
material
Drying
Baking
Shaping
of
clay
Distribu;on
(diesel)
kWh
0
50
100
150
200
250
Solid
waste
Eutrophica;on
Acidifica;on
Global
worming
* Koroneos C and Dompros A. (2007); Environmental assessment of brick production in Greece. Building and Environment
42: 2114-2123.

22. 100
90
80
70
60
50
40
30
20
10
0
CEM
I
CEM
III
0%
recycled
10%
recycled
20%
recycled
30%
recycled
40%
recycled
Comparison with similar LCA
Ø Cement composition and aggregates recycling
From (Blankendaal et al. 2014)*:
Decrease up to 30% of the total impact could be achieved substituting Portland cement
with slag cement, while increasing from 0% up to 40% the quantity of waste material
replacing gravel as aggregate, the reduction of the total impact was negligible
CEM
I=
100%
Portland
Cement
CEM
III=
50%
Portland
Cement+
50%
slag
* Blankendaal T, Schuur P and Voordijk H. (2014) ; Reducing the environmental impact of concrete and asphalt: a scenario
approach. Journal of Cleaner Production 66: 27-36.

23. Conclusions
Ø Saving energy
Solid AAbricks and perforated carbonated bricks lower the energy
consumption (electricity or fossil fuels), which is the highest impact for
conventional clay bricks (during baking stage).
Ø Cement production
Aerated AAbricks decrease the impact of cement production in traditional
autoclaved bricks.
Ø Alkali production
Alkali activation requires high quantity of alkali activators.
Ø Avoided landfilling of slag
Lower stress on the use of virgin materials but also to saved impacts arising
from the handling of the slag in landfill
Ø Disposal phase
It seems not to account significantly on the final results, and the reuse of waste
bricks as aggregates has little effect on decreasing the total impact.
23

24. Thank you
for
your attention!
andrea.dimaria@kuleuven.be