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

isabella.lancellotti@unimore.it

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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t

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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

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p

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l

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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