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Geopolimerizzazione per la valorizzazione di rifiuti non pericolosi e l'inertizzazione di
rifiuti pericolosi
I. Lancellotti, L. Barbieri, C. Leonelli
Dipartimento di Ingegneria “Enzo Ferrari” (DIEF), Università di Modena e Reggio
Emilia, Via Vivarelli 10, 41125 Modena, Italy
IWIW 2016 - International Workshop on Industrial Waste
Approaches and Technologies for the Recovery of Raw Materials by Complex Products End of Life
Genoa, Italy, February 17 2016
Geopolymers in Italy
Established in 2008
@ Italian Ceramics Society-ICerS
the
Geopolymers Working Group
Coordinated by DIEF, Prof. C. Leonelli
40 members (9-10 universities
4-5 National Research Centres
and 4-5 industries)
Wastes inertization/valorization (1)
Since 1986 we have experience in inertization hot techniques:
Since 2008: alkali activation and room temperature consolidation
Natural SOLIDS
Material Matrix Additives
Laterites
Pumices
Kaolin
Metakaolin
Volcanic ash
Wastes inertization/valorization (2)
Wastes/SOLIDS
Material Matrix Additives Incinerator bottom ash
Incinerator fly ash
Porcelain stoneware polishing sludges
Natural stone cutting sludge
Waste glass
Wastewater treatment sludge
Ladle slags
Bagasse ash
Waste/LIQUID
Cr containing waste as additives (deposited Patent N. dep. : RE2012A000028, 12/04/2012)
I geopolimeri: strutture amorfe
di polimeri inorganici
• Formula empirica proposta da Davidovits:
• Rn[-(SiO2)z-AlO2-]n . wH2O
• R = ioni alcalini( K+, Na+, …),
• n = grado di policondensazione
• w = acqua legata
• z=1,2,3 è indicativo del reticolo ed è generalmente
<3 per geopolimeri strutturali tridimensionali
Reagenti
• Materia prima alluminosilicatica • Soluzione di metallo alcalino
(idrossido e/o silicato): ATTIVATORE CHIMICO
Reagenti
Materia prima alluminosilicatica
• Caolini, metakaolini ed altre argille
• Ceneri volanti da centrali a carbone
• Scorie d‘altoforno macinate, granulate
• Residui del processo della bauxite
• Pozzolana
• Ceneri vulcaniche
• etc
La chimica del processo La struttura a livello atomico
Dissoluzione di metacaolino in ambiente basico
4 NaOH + Si4+
OH
|
HO Si OH + 4 Na+
|
OH 4 NaOH + Al3+ OH
| Na+
HO Al- OH + 3 Na+ |
OH
Stadi di condensazione delle catene di silicati pre-
idrolizzati in ambiente basico: la catena formata, che può
contenere anche tetraedri con alluminio, dà origine ai
geopolimeri.
La chimica del processo La struttura a livello atomico
La struttura a livello atomico
polimerizzazione
Rapporti importanti
Na/Al
Na/Al = 1 per materiali tridimensionali utilizzabili come cementi
ioni non compensati:
-carbonatazione con formazione di fratture e tensioni.
-in presenza di umidità ed acqua possono scambiarsi con lo ione H+ generando cricche
Si/Al influenza le proprietà fisiche •Si/Al < 3:1, reticolo tridimensionale rigido, adatto come cemento,
calcestruzzo o per immmobilizzazione di rifiuti
•Si/Al ratio > 3, meno rigido e più flessibile "polymer-like"
Si/Al fino a 35:1, struttura bidimensionale adatto come adesivo
Composizione chimica del materiale
Al2O3 Na2O + CaO
SiO2
geopolimeri
Vetri
Cementi
GEOPOLIMERI COME MATERIALI SOSTENIBILI
Prodotti ad elevata durezza e interessanti proprietà estetiche, ottenuti a freddo;
In sostituzione del cemento Portland, permettono una forte riduzione delle emissioni di CO₂;
NB: 1 ton di cemento produce 1 ton di CO₂!!
Possibilità di inertizzare rifiuti pericolosi, e valorizzare rifiuti non pericolosi per ottenere poi materiali da costruzione.
MATRICE SILICOALLUMINOSA, possibili vari materiali:
Metacaolino; Rocce vulcaniche; RIFIUTI.
DIFFERENTI APPROCCI NELLA PROGETTAZIONE DI UN
GEOPOLIMERO
RIFIUTO NON PERICOLOSO
• Composizione alluminosilicatica
• Inserito in grandi % in sostituzione di materie prime vergini per creare
la matrice geopolimerica
RIFIUTO PERICOLOSO
Inserito in piccole % per bloccare metalli pesanti e/ ioni
solubili nella matrice geopolimerica
VALORIZZAZIONE
INERTIZZAZIONE
Aluminosilicate as sustainable
precursor (1): Incinerator bottom ash
INCINERATION ADVANTAGES
90% VOLUME REDUCTION
AND ENERGY PRODUCTION
BOTTOM ASH
(30% in weight of input waste)
HEAVY METALS (Pb, Cd, Cr, Mn, Cu... )
SOLUBLE SALTS (Na+, K+, Cl-, HCO3-, SO4
-- )
FLY ASHES
(3% in weight of input waste)
INCINERATION DRAWBACKS
collected from air pollution
control devices (electrofilters
and fabric filters) NOT DANGEROUS
WASTE
Isabella Lancellotti, Chiara Ponzoni, Luisa Barbieri, Cristina Leonelli, Alkali activation processes
for incinerator residues management” Waste Management, 33 (8), 2013, 1740-1749
European regulation 2008/98 /CE
Introduce in the waste hierarcy
Preparing for re-use
Regulation
Prevention
Preparing for
re-use
Recycling
Disposal
Recovery of
other type
End of Waste Material coming from
MSWI bottom ash treatment
Technological Recovery Process
Sorting Artificial aggregate, silica based
and rich in Ca, Al and Fe, with
controlled grain size, suitable
for cements and ceramics
Physical-Mechanical
treatments
aging,
Fe and non Fe metals
separation,
crushing, sieving,
washing,…
After treatment the inert material is delivered as EOW, it has not a
EWC code and the companies do not need the authorization for
using it inside the process.
Incineration bottom ash (IBA) ‘‘end of waste material’’
Chemical and mineralogical characterization
Element Concentration (wt%)
Si 33.26
Ca 21.27
Al 3.96
Na 3.21
Fe 2.46
Mg 2.71
K 1.03
P 0.31
Ti 1.22
S 0.33
Zn 0.53
Ba 0.45
Pb 0.45
Cu 0.36
Mn 0.13
Cr 0.04
Ni 0.03
CO3-2 13.21
C 2.57
H 0.63
N 0.00
LOI 7.00
SO4-2 2.37
Cl- 1.29
Amorphous and
crystalline material
Preparation Mixture formulation
Geopolymer formulations
Sample Bottom
ash
(BA)
Metakaolin
(MK)
NaOH 8M Na
Silicate
H2O Si/Al Na/Al
50_50 MK_BA 25 g 25 g 12 ml 15 ml - 2.5 1.09
40_60 MK_BA 30 g 20 g 12 ml 8 ml 3 ml 2.63 1.10
30_70 MK_BA 35 g 15 g 7 ml 10 ml 3 ml 3.26 1.09
20_80 MK_BA 40 g 10 g 10 ml 5 ml 7 ml 3.8 1.5
Setting stage maintaining the cast at room temperature in polymeric
mould
Curing stage at room temperature 15 or 30 days
Samples cured for 15 days
(dense materials)
a) 50 wt% (b) 60 wt% (c) 70 wt% (d) 80% of IBA
Geopolymeric
samples after test
of immersion in
water for 48 h
homogeneous
geopolymeric gel
with dispersed
particles of not
completely reacted
bottom ash.
Not further studied
Si/Al ratio vs curing time
Increase of the ratio with the
curing time, due to the necessity of
time to complete ash reaction
longer times can favor further
reactivity towards geopolimerization
of bottom ash
The Si/Al values ranges between
1.5 and 2.2 corresponding to the
value accepted in literature for
structural materials.
Conductivity vs IBA content
and curing time
Both Na+ and OH- ions, which
possess a particularly high
equivalent conductivity, give a
significant effect on the overall
solution conductivity.
• Higher values for
compositions with higher
amount of bottom ash.
• Improvement in chemical
stability (decreasing in
conductivity), with the
curing time.
Determination of reactive fraction
of IBA and reformulation
Basic attack : 5hs in NaOH 8M at 80°C.
Si and Al analyzed by ICP to determine Si/Al reactive •Ruiz-Santaquiteria, C., Fernández-Jiménez, A., Palomo, A., 2011. Quantitative determination of reactive SiO2 and Al2O3 in aluminosilicate
materials. In:Proceedings of XIII International Congress on the Chemistry of Cement, Madrid,Spain.
Sample Bottom
ash
(BA)
Metakaolin
(MK)
NaOH
8M
Na-
Silicate
H2O Si/Al Na/Al Si/AlR Na/AlR
50_50MK_BAR 25 g 25 g 8 ml 20 ml - 2.5 1.09 2.03 1.11
40_60MK_BAR 30 g 20 g 5 ml 18 ml 1 ml 2.63 1.10 2.14 1.13
30_70MK_BAR 35 g 15 g 5 ml 12 ml 3 ml 3.26 1.09 2.06 1.24
Obtained taking into account the
reactive fraction of bottom ash
Reactive fraction of IBA
Bottom ash before
and after treatment in
NaOH 8M
Amorphous fraction
decreases
reacts
Microstructural modification
50-50 MK_BA 50-50 MK_BA after reformulation.
Samples cured for 15 days
Sample after reformulation is more
homogeneous and dense
Modification of Si/Al ratio
increase of Si/Al(wt%)
ratio
bottom ash are not completely
constituted of a reactive
fraction
taking into account the real
active fraction,
gel is more dense and
compact with ratios near to
optimum values for
structural materials (1.5-2.5). measurement by EDS
CONCLUSIONS 1
Possibilità di ottenere materiali densi a partire da
end of waste (azienda non deve avere
autorizzazioni per gestire rifiuti)
Importanza della composizione chimico-
mineralogica del rifiuto perché influisce sulla
reattività in ambiente alcalino
Non sono richiesti trattamenti termici (eccetto
calcinazione di metacaolino)
No emissioni di gas
Geopolymers as inertization matrix for
hazardous liquid waste Brevetto102012902041083 (RE2012A000028) 19-09-2014
Inertization of an industrial Cr containing liquid waste
from the inks for the digital decoration of ceramic tiles
(Cr develops color during the firing cycle)
No drying steps
No electro-reduction processes
on the liquor
Chiara Ponzoni, Isabella Lancellotti, Luisa Barbieri, Alberto Spinella, Maria Luisa Saladino, DeliaChillura Martino,
Eugenio Caponetti, Francesco Armetta, Cristina Leonelli Chromium liquid waste inertization in an inorganic alkali
activated matrix: Leaching and NMR multinuclear approach, Journal of Hazardous Materials, 286, 2015, 474-483.
Dry residue: solid phase 33 wt% (Cr content in the dry
residue is around 25 wt%) Calcination: 27% Inorganic residue, 73% Organic fraction.
LIQUID PHASE (67wt%): H2O
pH: 3,07 Density: 1,213 g/ml
Soluble salts of metals: Clorides: 700 mg/l Sulphates: 12500 mg/l
SOLID PHASE
Characterization of Cr liquid waste
Chromium liquid waste
Solid fraction Characterization
• C (17,2%) =
significant organic
fraction (73 wt%)
• N (5.01%)could
indicate the presence
of ammonium ions
• Presence of both Cr3+
and Cr6+
Chromium liquid waste Waste Characterization – FTIR spectroscopy
• Oxalate
group
• Ammonium
N-H
C=O Anti symmetric
mode
Oxalate Cr-O
O-C=O
C=O Symmetric mode
Cr complex
Chromium liquid waste Waste Characterization
Thermal analysis (TG/DTA)
Oxalate group
decomposition
Cr complex salt formula:
(NH4)[Cr(C2O4)2].2H2O
Water and NH4 evaporation
Cr(OH)3 ----- Cr2O3
CO32- ----CO2
Preparation of geopolymers
containing liquid waste
Setting stage: room T
Curing stage: room T for 15,
28, 90 and 540 days.
Four formulations of MK based geopolymers
containing 3, 5, 10 or 20 wt% of liquid waste.
Geopolymers Leaching behaviour
(EN 12457 distilled water, 24h, stirring, S/L = 10)
• up to 10 wt% of waste, Cr
release falls within the
limit for non-dangerous
waste landfill disposal:,
• 3–5 wt% below the limit
after 15 days,
• 10 wt% needs more time
(28 days).
• Inertization capability
increase with curing
time
three-dimensional
geopolymeric network - Limit set by Italian regulation (DM
30/08/2005) for non-dangerous
waste landfill disposal
SULPHATES RELEASE
Sample 1, 2, 3, 4 = containing 3, 5, 10 and 20wt%
Law limit 2000mg/l
Limit set by Italian regulation (DM
30/08/2005) for non-dangerous
waste landfill disposal
Sulphates in the waste: 12500 mg/l
Geopolymers
Microstructural characterization (SAMPLE = 10wt%)
Na-oxalate
Cr well
dispersed in
geopolymeric
gel (0,1-1wt%)
Cr enriched in
sponge-like
microstructure
Geopolymers Hardness and microstructure
• high hardness and hardly pulverized
• no macroporosity
• evolution of the consolidation process from 15 to 540 days
Long term stability of these materials (confirmed by the
decreasing of leaching values at long curing times).
Curing 15 days Curing 540 days
300X 300X
CONCLUSIONS (2)
Possibilità di inertizzare un rifiuto liquido pericoloso derivante dalla
decorazione digitale delle piastrelle fino ad un 10%.
Nessun pre-trattamento di essicazione (risparmio energetico
minore manipolazione del rifiuto ).
Struttamento del contenuto di acqua nel rifiuto per ottenere una
pasta colabile
Risultati incoraggianti per testare inertizzazione anche di altri
metalli nella stessa matrice.
Dr. Mirko Braga R.S.A. Laboratory, INGESSIL S.r.l.,
Montorio (Verona).
Acknowledgments
First book on Geopolymers
In Italian
2011 (2nd Edition 2013)
Print on demand
www.lulu.com
13 chapters - 17 coauthors
Book -1
G
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o
p
o
l
I
t
a
l
y
Book - 2
Handbook of Alkali-Activated
Cements, Mortars and Concretes
Edited by: Fernando Pacheco-
Torgal, João Labrincha, C Leonelli,
A Palomo, P Chindaprasit
Elsevier 2014 Technology & Engineering - 858
pages
G
e
o
p
o
l
W
o
r
l
d
Book - 3
Geopolymers: the route to eliminate
waste emissions in ceramic and cement
manufactirung
Edited by:
C. Leonelli, M. Romagnoli, 2015
ISBN: 978-1-326-37732-8
Print on demand
www.lulu.com