research article low temperature synthesis of belite...

Research ArticleLow Temperature Synthesis of Belite CementBased on Silica Fume and Lime

M A Tantawy1 M R Shatat2 A M El-Roudi1 M A Taher2 and M Abd-El-Hamed2

1 Chemistry Department Faculty of Science Minia University Minia 61111 Egypt2 Chemistry Department Faculty of Science Al-Azhar University Assiut 71524 Egypt

Correspondence should be addressed to M A Tantawy matantawy75yahoocom

Received 17 May 2014 Revised 3 July 2014 Accepted 4 July 2014 Published 29 October 2014

Academic Editor Tomasz Czujko

Copyright copy 2014 M A Tantawy et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This paper describes the low temperature synthesis of belite (120573-C2S) from silica fume Mixtures of lime BaCl

2 and silica fume

with the ratio of (Ca + Ba)Si = 2 were hydrothermally treated in stainless steel capsule at 110ndash150∘C for 2ndash5 hours calcined at600ndash700∘C for 3 hours and analyzed by FTIR XRD TGADTA and SEM techniques Dicalcium silicate hydrate (hillebrandite)was prepared by hydrothermal treatment of limesilica fume mixtures with (Ca + Ba)Si = 2 at 110∘C for 5 hours Hillebranditepartially dehydrates in two steps at 422 and 508∘C and transforms to 120574-C

2S at 734∘C which in turn transforms to 1205721015840-C

2S at 955∘C

which in turn transforms to 120573-C2S when cooled In presence of Ba2+ ions 120573-C

2S could be stabilized with minor transformation to

120574-C2S Mixture of silica fume lime and BaCl

2with the ratio of (Ca + Ba)Si = 2 was successfully utilized for synthesis of 120573-C

2S by

hydrothermal treatment at 110∘C for 5 hours followed by calcination of the product at 700∘C for 3 hours

1 Introduction

Portland cement is a hydraulic binder forming a paste withwater which sets and hardens due to hydration reactions[1] The main constituent of Portland cements is clinkerwhich itself is composed of 40ndash80wt tricalcium sili-cate 3CaOsdotSiO

2(alite C

3S) 10ndash50wt dicalcium silicate

2CaOsdotSiO2(belite C

2S) 0ndash15wt tricalcium aluminate

3CaOsdotAl2O2(aluminate C

3A) and 0ndash20wt tetracalcium

aluminoferrite 4CaOsdotAl2O3sdotSiO2(ferrite C

4AF) [2] Alite

and belite determine most of the adhesive propertiesstrength and durability of Portland cement Both alite andbelite show the same physical and mechanical propertiesafter complete hydration but the former hydrates much faster[3] Cement industry is responsible for approximately 5of total CO

2emissions [4] About 900ndash1000 kg CO

2per

tonne of clinker is released due to calcination of CaCO3

and fuel combustion [2 5] The demand for thermal energyequals sim3000ndash4000MJtonne of clinker for dry process[2] Additionally sim324ndash540MJtonne of cement of electricalenergy is required for grinding of raw materials and cement[6]The production temperature of belite is lower than that of

alite In contrast belite has low reactivity than alite renderingit much less useful The high reactivity of alite is related tothe reactive sites around its more ionic oxygen atoms that arenot contained in belite [7] Attempt to improve the reactivityof belite phase in order to reduce energy requirements forcement production is one of the most important challenges

Belite has five polymorphs (120573 120574 120572 1205721015840H and 1205721015840

L) under-going reversible temperature dependent transformations asillustrated in Figure 1 [8] The 1205721015840H 120572

1015840

L and 120573 polymorphs arederived from the 120572 form by a decrease of the symmetry dueto the disorder of SiO

4

minus4 groups and slight changes in theposition of Ca atoms [9] The 1205721015840-polymorphs are the mosthydraulic forms of belite 120573-belite is also a hydraulic but lesshydraulic than the 1205721015840-polymorphs 120574-belite is a nonhydraulicpolymorph and does not account for the setting and hard-ening of cement 120573-belite is the most common polymorphin industrial Portland cement clinker [10] 120574-C

2S crystals are

less dense (more voluminous) than 120573-C2S crystals which

causes cracking of other 120573-C2S crystals forming voluminous

powder and dust Dusting phenomenon can be preventedif 120573-C

2S is stabilized by fast cooling andor by inclusion

of stabilizing ions Fe3+ Al3+ Mg2+ Zn2+ Cr3+ Pb2+ B3+

Hindawi Publishing CorporationInternational Scholarly Research NoticesVolume 2014 Article ID 873215 10 pageshttpdxdoiorg1011552014873215

2 International Scholarly Research Notices

120574-C2S 120572998400L-C2S 120572998400H-C2S 120572-C2SOrthorhombic OrthorhombicOrthorhombic Hexagonal

120573-C2SMonoclinic

sim700∘C 1160∘C 1450∘C

60sim80∘C

Figure 1 Polymorphs of belite

Na+ and K+ can replace calcium andor silicon atoms in thestructure and reduce the CaSi ratio of 120573-C

2S to less than 2

[11 12] Reactivity and hydraulic properties of stabilized 120573-C2S depend on the type and amount of the stabilizing ions

[13] On the other hand fast cooling may produce fine 120573-C2S crystals affording 120573-120574-C

2S transformation even without

the need for stabilizer [14] Based on density functionaltheory calculations stabilizing ions modify charge densitylocalization of the electronic structure of C

2S and enhance

the reactivity and in turn would broaden the applicability ofC2S [7]Synthesis of low-energy belite cement as an alternative

to the conventional Portland cement was carried out in twostepsThefirst step is preparation of dicalcium silicate hydrate(hillebrandite Ca

2(SiO3)(OH)

2) by hydrothermal treatment

of silica rich waste materiallime mixtures Hillebrandite wassynthesized by hydrothermal treatment of quartz and limewith CaSi = 20 at 200∘C for 10 hours or at 250∘C for 5hours [15] The main silicate anion structure of hillebranditestudied by 29Si MAS NMR analysis is a mixture of a dimerand a single-chain polymer (larger than Si

5O16) and that

polymerization advancedwith an increase of the synthesizingtemperature [16] Different polymorphs of calcium silicatehydrates with CaSi = 20 namely 120572-C

2SH [Ca

2(SiO4H)OH]

dellaite [Ca6Si3O11(OH)2] and hillebrandite were synthe-

sized and their stability and phase transformation wereinvestigated under hydrothermal conditions up to 400∘C 120572-C2SH completely transforms to dellaite at 350∘C for 1 hour

which in turn undergoes a reversible phase transformationto hillebrandite at low temperatures below 300∘C [17] Hille-brandite was synthesized by mechanochemical treatment ofamorphous precipitated silicalime using a vibration mill atroom temperature [18] The second step involves calcinationof hillebrandite to prepare belite Hillebrandite starts todecompose at about 500∘C producing low-crystalline 120573-C

2S

[15] Moreover 29Si MAS NMR analysis illustrates that thetemperature at which 120573-C

2S begins to form decreases as

the CaSi ratio of hillebrandite becomes higher [19] or asthe temperature of hydrothermal synthesis of hillebranditebecomes higher [16] On the other hand XRD analysisillustrates that the crystallographic properties and density ofdissociation products of 120572-C

2SH depend on the calcination

temperature [20] 120572-C2SH dissociates at 390ndash490∘C forming

an intermediate phase plus 120574-C2S The intermediate phase

then transforms to 1205721015840L phase at 920ndash960∘C and yields 120573-C

2S

on cooling while hillebrandite yields 120573-C2S at the lowest tem-

perature [21] Hillebrandite synthesized bymechanochemicaltreatment of amorphous precipitated silicalime decomposedinto 120573-C

2S below 1000∘C [18]

The reactivity of 120573-C2S relates to its large specific surface

area taking into consideration the fact that the hydration ischemical-reaction-rate-controlled until its completion [19]The specific surface area of 120573-C

2S depends on calcination

temperature of hillebrandite The hydration rate of 120573-C2S

enhanced with increasing surface area The specific surfacearea affects the hydration reaction mechanism In the caseof specific areas of 55m2g or less the reaction changesfrom a chemical reaction to a diffusion-controlled one [22]The hydration rate of 120573-C

2S enhances with raising curing

temperature of hydration [23] The hydration rate of 120573-C2S

enhancedwith dynamicmore than static hydration condition[24] At early ages of hydration 120573-C

2S yields CndashSndashH with

a CaSi ratio of 181 plus Ca(OH)2 At later ages CndashSndashH

and Ca(OH)2react to form a CndashSndashH(II)-like monophase

hydrate having aCaSi ratio of 198with differentmorphology[24] The hydration rate of the 120573-C

2S also enhances with

increasing watersolid ratio [25] Recent works presentedalternative cements containing higher amounts of 120573-C

2S in

their composition based upon the use of waste materialssuch as rice hull and husk ash as well as coal fly ash [15 2627] Silica fume is an abundant material produced in manycountries as a waste product from silicon industry around theworld containing approximately 90ndash97 os SiO

2 Silica fume

have average particle size lt1 120583m specific surface area of 13ndash30m2g and specific gravity of 222 Reuse of waste materialsseems to be a good approach to solve both economic andenvironmental issues related to cement production [28ndash30]This work describes a method for the production of 120573-C

2S

from silica fume

2 Materials and Experimental Techniques

Freshly prepared lime was prepared by calcination of lime-stone powder (purity gt 99) in an electrical muffle furnaceat 950∘C for 3 hours Lime was cooled to room temperaturein desiccator milled and stored in tightly closed plasticbottle to avoid carbonation Silica fume was purchasedfrom Ferrosilicon Company Edfo Egypt Distilled water andanalytical grade barium chloride were used without further

International Scholarly Research Notices 3

Table 1 Mixtures of silica fume and lime with and without BaCl2hydrothermally treated and calcined at different conditions

Number Hydrothermal treatment conditions1 Silica fume lime treated at 110∘C for 2 hours2 Silica fume lime with BaCl2 treated at 110∘C for 2 hours3 Silica fume lime treated at 110∘C for 5 hours4 Silica fume lime with BaCl2 treated at 110∘C for 5 hours5 Silica fume lime treated at 150∘C for 2 hours6 Silica fume lime with BaCl2 treated at 150∘C for 2 hours7 Silica fume lime treated at 150∘C for 5 hours8 Silica fume lime with BaCl2 treated at 150∘C for 5 hours

purification Preparation of hillebrandite by hydrothermaltreatment of silica fume and lime with and without 2wtBaCl2was carried out as described below Mixtures of silica

fume and limewith andwithout BaCl2keeping the ratioCaSi

or (Ca + Ba)Si = 20 were hydrothermally treated at 110 or150∘C for 2 or 5 hours as illustrated in Table 1

Mixtures of silica fume lime and BaCl2were added to

distilled water at watersolid ratio of 51 by weight in stainlesssteel capsule keeping the occupied volume equal to 067 ofthe total volume capacity The capsule was tightly closedto avoid sealing of water vapor The capsule was shackedto obtain homogeneous suspension inside The capsule washeated in electric oven for appropriate temperature andtime At the end of the hydrothermal treatment processthe capsule was removed from oven and cooled to roomtemperature The product of hydrothermal treatment (hille-brandite) was filtered washed with distilled water and driedunder vacuum Preparation of 120573-C

2S was carried out by

calcination of hillebrandite in an electric muffle furnace at600 or 700∘C for 3 hours At the end calcination process thecalcined product (120573-C

2S) was cooled to room temperature

in desiccator milled and stored in tightly closed plasticbottles X-ray fluorescence XRF and X-ray diffraction XRDanalyses were carried out by Philips X-ray diffractometerPW 1370 Co with Ni filtered CuK

120572radiation (15406 A) The

Fourier transform infrared FTIR analysis was measured byspectrometer Perkin Elmer FTIR System Spectrum X in therange of 400ndash4000 cmminus1 with spectral resolution of 1 cmminus1Scanning electron microscopy SEM was investigated by Jeol-Dsm 5400 LG apparatus The thermogravimetric TGA anddifferential thermogravimetric analyses DTG were carriedout with the aid of Shimadzu Corporation thermoanalyzerwith DTG-60H detector with 10∘Cmin heating rate fromroom temperature up to 1000∘C under nitrogen atmosphereat 40mLmin flow rate the hold time at the appropriatetemperature is zero

3 Results and Discussion

31 Characterization of StartingMaterials Figure 2 illustratesthe XRD patterns of limestone and silica fume Table 2illustrates the chemical composition of limestone and silicafume inferred by XRF The chemical composition resultsconfirm XRD results indicating that limestone is mainly

15 20 25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(a)

(b)

C

C

C C C

Figure 2 XRD patterns of (a) limestone and (b) silica fume (whereC is calcite)

0

25

50

75

100

125

150

40080012001600200024002800320036004000

Tran

smitt

ance

()

Wavenumber (cmminus1)

1101

796

467

Figure 3 FTIR spectrum of silica fume

composed of calcite (CaCO3) while silica fume is mainly

composed of amorphous silica as indicated by a broad humpat around 20ndash25∘2120579 Figure 3 illustrates the FTIR spectrumof silica fumeThemost significant absorption bands of silicaappear at 1101 796 and 467 cmminus1 corresponding to asym-metric stretching vibration of SindashOndashSi symmetric stretchingvibration of SindashOndashSi and bending vibration of OndashSindashOrespectively [31] Figure 4 illustrates the SEM micrograph ofsilica fume Silica fume has a refined microstructure of highsurface area containing silica microspheres

32 Preparation of Hillebrandite Figures 5 and 6 illustrate theFTIR spectra of limesilica mixture hydrothermally treatedat 110ndash150∘C for 2ndash5 hours Hydrothermal treatment initi-ates the reaction between lime and reactive silica leadingto the formation of intermediate calcium silicates hydrate(hillebrandite) which gives rise to strong absorption band at950 cmminus1 (vibrations of SiO

4

minus4 groups) and strong absorptionbands at 2530 1800 and 330 cmminus1 [32] Unreacted silicagives rise to its absorption band at 1101 (SindashOndashSi asymmetricstretching vibration) [31] and unreacted lime gives rise toits absorption band at 3643 and 1450ndash1500 cmminus1 (vibrationsof OH group and CandashO stretching vibration) [32] Calcitearising from partial carbonation of unreacted lime gives itsabsorption bands at 2530 1800 1420 840 and 700 cmminus1[33] The existence of unreacted lime and silica indicates


Table 2 The chemical composition of limestone and silica fume inferred by XRF

Material SiO2 Al2O3 Fe2O3 CaO MgO SO3 Na2O K2O LOI TotalLimestone 026 016 000 5459 029 005 011 003 4372 9921Silica fume 9290 110 082 042 052 000 064 112 156 9908

Table 3 Result of thermal analysis

Number Phases Temperature(∘C)

Peak temperature(∘C)

Weight loss()

Weight loss(mg)

1 Loss of absorbed water 30ndash287 109 685 05552 Hillebrandite partial dehydration 288ndash590 422 508 253 0205

3 Hillebrandite complete dehydration(formation of 120574-C2S)

593ndash781 734 196 160

4 120574-C2S rarr 1205721015840-C2S transformation 850ndash985 955 mdash mdash

Total 2898 236

1120583m

Figure 4 SEM micrograph of silica fume

0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

11011450

1800

2530

3643

Figure 5 FTIR spectra of limesilica mixture hydrothermallytreated at 110∘C for (a) 2 hours (b) 5 hours

that the hydrothermal treatment of the limesilica mixture(CaSi = 21) at 110∘C for 2 hours does not drive thereaction to completion FTIR indicates that the chance offormation hillebrandite was improved by increase of bothtime (Figure 5) and temperature (Figure 6) of hydrothermaltreatmentThis is confirmed by disappearance of lime and thedecreasing amount of unreacted silica From economic pointof view the best conditions (heating at 110∘C for 5 hours)

0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

1101

1450

1800

2530

3643

Figure 6 FTIR spectra of limesilica mixture hydrothermallytreated for 2 hours at (a) 110∘C (b) 150∘C

were selected for the hydrothermal treatment of silicalimemixtures

Figure 7 illustrates TGADTA thermogram of limesilicamixture hydrothermally treated at 110∘C for 5 hours Result ofthermal analysis was illustrated in Table 3 Hillebrandite lostabsorbed water at 109∘C Hillebrandite partially dehydratedin two steps at 422 and 508∘CHillebrandite completely dehy-drated forming 120574-C

2S at 734∘C Finally 120574-C

2S transformed

to 1205721015840-C2S at 955∘C [34] When allowed to cool to room

temperature 1205721015840-C2S may transform 120573-C

2S instead of 120574-C

2S

as illustrated in Figure 1 Fast cooling and presence of Ba2+ions may stabilize 120573-C

2S [13]

33 Preparation of Belite Figure 8 illustrates the FTIR spectraof limesilica mixture hydrothermally treated at 110∘C for 5hours and calcined at 600ndash700∘C for 3 hours As determinedby TGADTA results hillebrandite completely dehydratesforming 1205721015840-C

2S that transforms to 120573-C

2S andor 120574-C

2S after

cooling C2S gives rise to the following absorption bands

three maxima at 1000 910 and 840 cmminus1 (SindashO asymmetricstretchingmodes) medium intensity band at 430 cmminus1 (SindashObending mode) and a strong band at 530 cmminus1 (SindashOndashSi out


minus12

minus4

4

12

68

76

84

92

100

0 500 1000

DTA

(120583V

)

TGA

()

Temperature (∘C)

109 422 508

734

955

TGA

DTA

1

2

43

Figure 7 TGADTA thermogram of limesilica mixture hydrother-mally treated at 110∘C for 5 hours

0

10

20

30

40

50

60

70

80

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


3643

1450

1000

910

430530

(c)

(b)

(a)

Figure 8 FTIR spectra of limesilica mixture hydrothermallytreated at 110∘C for 5 hours (a) before calcination (b) calcined at600∘C and (c) calcined at 700∘C

of plane bending mode) [35ndash37] C2S does not clearly appear

in sample that was calcined at 600∘C (Figure 8(b)) but clearlyappears in sample that was calcined at 700∘C (Figure 8(c))In general formation of C

2S was accompanied by liberation

of lime (absorption bands at 3643 and 1450ndash1500 cmminus1) Thisconfirms the TGADTA results which show that hillebranditecompletely dehydrated forming 120574-C

2S at 734∘C

Figure 9 illustrates XRD patterns of limesilica mixturehydrothermally treated at 110∘C for 5 hours calcined at600ndash700∘C for 3 hours Hillebrandite does not appear inthe XRD analysis (Figure 9(a)) because of its gel structureC2S does not appear in the sample that was calcined at

600∘C (Figure 9(b)) The mixture of 120574-C2S (major) and 120573-

C2S (minor) appears in the sample that was calcined at

700∘C (Figure 9(c))This proves that120573-C2Swas not stabilized

by fast cooling and transforms to 120574-C2S [11 12] Figure 10

illustrates XRD patterns of (lime + BaCl2)silica mixture

hydrothermally treated at 110∘C for 5 hours calcined at 600ndash700∘C for 3 hours In this case the situation is reversedThe mixture of 120573-C

2S (major) and 120574-C

2S (minor) appears

in the sample that was calcined at 700∘C (Figure 10(b)) This

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)

PC B BG

C

C C

(a)C

(c)

Figure 9 XRD patterns of limesilica mixture hydrothermallytreated at 110∘C for 5 hours (a) before calcination (b) calcined at600∘C and (c) calcined at 700∘C (where C is calcite P is portlanditeG is 120574-C

2S and B is 120573-C

2S)

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)P

C

C

B BG

CC

C

(a)

C

Figure 10 XRDpatterns of (lime +BaCl2)silicamixture hydrother-

mally treated at 110∘C for 5 hours and then calcined for 3 hours at (a)600∘C and (b) 700∘C (where C is calcite P is portlandite G is 120574-C

2S

and B is 120573-C2S)

indicates that 120573-C2S was stabilized by Ba2+ ions with minor

transformation to 120574-C2S In other words Ba2+ ions replace

calcium andor silicon atoms and hence it stabilizes thestructure of belite and prevents the transformation of 120573-C

2S

to 120574-C2S [13]

Figures 11 and 12 illustrate the SEM micrographs ofmixture of silica fume and lime hydrothermally treated at110ndash150∘C for 2ndash5 hours The mixtures of silica fume andlime that were hydrothermally treated at 110∘C for 2 hours


1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)

Figure 11 SEM micrographs of mixture of silica fume and lime hydrothermally treated at 110∘C for (a) 2 hours without BaCl2 (b) 2 hours

with BaCl2 (c) 5 hours without BaCl

2 and (d) 5 hours with BaCl

2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m

Figure 13 SEMmicrographs of mixture of silica fume and lime represented in Figure 11 after being calcined at 600∘C (right) and 700∘C (left)

contain little amount of hillebrandite of low densitywithweb-like morphology (Figures 11(a) and 11(b)) On the other handthe mixtures that were hydrothermally treated at 110∘C for 5hours contain higher amount of hillebrandite of low densitywith web-like morphology (Figures 11(c) and 11(d)) Themorphology of the hillebrandite greatly changes with raisingthe temperature of the hydrothermal treatmentThemixturesof silica fume and lime that were hydrothermally treated at150∘C for 2ndash5 hours withwithout BaCl

2addition contain

high amount of short fibrous hillebrandite of high density

(Figures 12(a)ndash12(d)) Figure 13 illustrates the SEM micro-graphs of mixtures of silica fume and lime hydrothermallytreated at 110∘C for 2ndash5 hours after being calcined at 600ndash700∘C As determined by TGADTA results mixtures thatwere calcined at 600∘C contain partially dehydrated calciumsilicate with glass-like morphology (Figures 13(a)ndash13(d)) Onthe other hand mixtures of silica fume and lime that werecalcined at 700∘C contain fine 120573-C

2S crystals (Figures 13(a1015840)

and 13(c1015840)) The amount of fine 120573-C2S crystals markedly

increases in case ofmixture of silica fume and limewith BaCl2


(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m


addition (Figures 13(b1015840) and 13(d1015840))This confirms TGADTAresults Figure 14 illustrates the SEMmicrographs ofmixturesof silica fume and lime hydrothermally treated at 150∘C for 2ndash5 hours after being calcined at 600ndash700∘CMixtures that werecalcined at 600∘C still contain partially dehydrated calciumsilicate with glass-likemorphology (Figures 14(a)ndash14(d))Theamount of fine 120573-C

2S crystals formed in mixtures that were

calcined at 700∘C is not affected by raising the temperature

of the hydrothermal treatment even in presence of BaCl2

addition (Figures 14(a1015840) and 14(d1015840))

4 Conclusions

The following is concluded(1) FTIR results show that hillebrandite was successfully

prepared by hydrothermal treatment of limesilica


fume mixtures with (Ca + Ba)Si = 2 at 110∘C for 5hours

(2) TGADTA results show that hillebrandite partiallydehydrates in two steps at 422 and 508∘C and trans-forms to 120574-C

2S at 734∘C that in turn transforms to 1205721015840-

C2S at 955∘C

(3) XRD results show that 1205721015840-C2S transforms to 120573-

C2S upon cooling In absence of Ba2+ ions 120573-C

2S

undergoes major transformation to 120574-C2S Whereas

in presence of Ba2+ ions 120573-C2S could be stabilized

with formation of little amount of 120574-C2S

(4) Mixture of silica fume lime and BaCl2with the

ratio of (Ca + Ba)Si = 2 was successfully utilizedfor synthesis of 120573-C

2S by hydrothermal treatment

at 110∘C for 5 hours followed by calcination of theproduct at 700∘C for 3 hours

Conflict of Interests

The authors declare that they have no conflict of interestsregarding the publication of this paper

References

[1] J P Jackson ldquoPortland cement classification andmanufacturerdquoin Learsquos Chemistry of Cement and Concrete P C Hewlett Ed p25 Butterworth-Heinemann Oxford UK 4th edition 2007

[2] ldquoEIPPCB (European Integrated Pollution Prevention and Con-trol Bureau) Reference Document on Best Available Tech-niques in Cement Lime andMagnesiumOxide ManufacturingIndustries European Commissionrdquo 2010

[3] J F Young and S Mindess Concrete Prentice-Hall UpperSaddle River NJ USA 1981

[4] E Worrell L Price N Martin C Hendriks and L O MeidaldquoCarbon dioxide emissions from the global cement industryrdquoAnnual Review of Energy and the Environment vol 26 pp 303ndash329 2001

[5] H G Van Oss and A C Padovani ldquoCement manufactureand the environment Part II Environmental challenges andopportunitiesrdquo Journal of Industrial Ecology vol 7 no 1 pp 93ndash126 2003

[6] V Johansen and T V Kouznetsova ldquoClinker formation and newprocessesrdquo in Proceedings of the 9th International Congress onthe Chemistry of Cement New Delhi India 1992

[7] E Durgun H Manzano R J M Pellenq and J C GrossmanldquoUnderstanding and controlling the reactivity of the calciumsilicate phases from first principlesrdquoChemistry of Materials vol24 no 7 pp 1262ndash1267 2012

[8] R Sakurada A K Singh T M Briere M Uzawa and YKawazoe ldquoCrystal structure analysis of dicalcium silicates byAb-initio calculationrdquo in Proceedings of the 32nd Conference onOur World in Concrete and Structures pp 28ndash29 Singapore2007

[9] X J Feng X M Min and C X Tao ldquoStudy on the structureand characteristic of dicalcium silicate with quantum chemistrycalculationsrdquo Cement and Concrete Research vol 24 no 7 pp1311ndash1316 1994

[10] S Telschow Clinker burning kinetics and mechanism [PhDthesis] Department of Chemical and Biochemical Engineering

Combustion and Harmful Emission Control Research CentreTechnical University of Denmark 2012

[11] G C Bye Portland Cement Composition Production andPreparation Pergamon Press Oxford UK 1st edition 1983

[12] H F Taylor Cement Chemistry Thomas Telford PublishingLondon UK 2nd edition 1997

[13] C J ChanWM Kriven and J F Young ldquoPhysical stabilizationof the 120573-120574 transformation in dicalcium silicaterdquo Journal of theAmerican Ceramic Society vol 75 no 6 pp 1621ndash1627 1992

[14] V K Peterson Diffraction investigations of cement and trical-cium silicate using Rietveld analysis [PhD thesis] Departmentof Chemistry Materials and Forensic Sciences University ofTechnology Sydney Australia 2003

[15] H Ishida K Mabuch K Sasaki and T Mitsuda ldquoLow-temperature synthesis of120573-Ca

2SiO4fromhillebranditerdquo Journal

of the American Ceramic Society vol 75 no 9 pp 2427ndash24321992

[16] Y Okada K Sasaki B Zhong H Ishida and T Mitsuda ldquoFor-mation processes of 120573-C

2S by the decomposition of hydrother-

mally prepared C-S-H with Ca(OH)2rdquo Journal of the American

Ceramic Society vol 77 no 5 pp 1319ndash1323 1994[17] X Hu K Yanagisawa A Onda and K Kajiyoshi ldquoStability and

phase relations of dicalcium silicate hydrates under hydrother-mal conditionsrdquo Journal of the Ceramic Society of Japan vol 114no 1326 pp 174ndash179 2006

[18] K Sasaki T Masuda H Ishida and T Mitsuda ldquoSynthesis ofcalcium silicate hydrate with CaSi = 2 by mechanochemicaltreatmentrdquo Journal of the American Ceramic Society vol 80 no2 pp 472ndash476 1997

[19] Y Okada H Ishida K Sasaki J F Young and T MitsudaldquoCharacterization of C-S-H from highly reactive 120573-dicalciumsilicate prepared from hillebranditerdquo Journal of the AmericanCeramic Society vol 77 no 5 pp 1313ndash1318 1994

[20] M Miyazaki S Yamazaki K Sasaki H Ishida and H TorayaldquoCrystallographic data of a new phase of dicalcium silicaterdquoJournal of the American Ceramic Society vol 81 no 5 pp 1339ndash1343 1998

[21] H Ishida S Yamazaki K Sasaki Y Okada and T Mitsudaldquo120572-Dicalcium silicate hydrate Preparation decomposed phaseand its hydrationrdquo Journal of the American Ceramic Society vol76 no 7 pp 1707ndash1712 1993

[22] K Sasaki H Ishida Y Okada and T Mitsuda ldquoHighly reactive120573-dicalcium silicate V influence of specific surface area onhydrationrdquo Journal of the American Ceramic Society vol 76 no4 pp 870ndash874 1993

[23] H Ishida K Sasaki Y Okada and T Mitsuda ldquoHighly reac-tive 120573-dicalcium silicate III hydration behavior at 40ndash80∘CrdquoJournal of the American Ceramic Society vol 75 no 9 pp 2541ndash2546 1992

[24] H Ishida K Sasaki A Mizuno Y Okada and T MitsudaldquoHighly reactive 120573-dicalcium silicate IV ball-milling and statichydration at room temperaturerdquo Journal of the AmericanCeramic Society vol 75 no 10 pp 2779ndash2784 1992

[25] H Ishida K Sasaki and T Mitsuda ldquoHighly reactive 120573-dicalcium silicate I hydration behavior at room temperaturerdquoJournal of the American Ceramic Society vol 75 no 2 pp 353ndash358 1992

[26] F A Rodrigues and P J M Monteiro ldquoHydrothermal synthesisof cements from rice hull ashrdquo Journal of Materials ScienceLetters vol 18 no 19 pp 1551ndash1552 1999


[27] W Jiang and D M Roy ldquoHydrothermal processing of new flyash cementrdquo American Ceramic Society Bulletin vol 71 no 4pp 642ndash647 1992

[28] P ArjunanM R Silsbee andDM Roy ldquoSulfoaluminate-belitecement from low-calcium fly ash and sulfur-rich and otherindustrial by-productsrdquo Cement and Concrete Research vol 29no 8 pp 1305ndash1311 1999

[29] A Ozturk Y Suyadal and H Oguz ldquoThe formation of belitephase by using phosphogypsum and oil shalerdquo Cement andConcrete Research vol 30 no 6 pp 967ndash971 2000

[30] A Guerrero S Goni A Macıas and M P Luxan ldquoHydraulicactivity and microstructural characterization of new fly ash-belite cements synthesized at different temperaturesrdquo Journal ofMaterials Research vol 14 no 6 pp 2680ndash2687 1999

[31] K Baltakys R Jauberthie R Siauciunas and R KaminskasldquoInfluence of modification of SiO

2on the formation of calcium

silicate hydraterdquo Materials Science vol 25 no 3 pp 663ndash6702007

[32] F A Rodrigues ldquoSynthesis of cements from rice hullrdquoAmericanChemical Society vol 39 no 2 pp 30ndash31 1999

[33] H Boke O Cizer B Ipekoglu E Ugurlu K Serifaki andG Toprak ldquoCharacteristics of lime produced from limestonecontaining diatomsrdquo Construction and Building Materials vol22 no 5 pp 866ndash874 2008

[34] C A S Oliveira A G Gumieri A M Gomes and W LVasconcelos ldquoCharacterization of magnesium slag aiming theutilization as a mineral admixture in mortarrdquo in InternationalRILEM Conference on the Use of Recycled Materials in Buildingand Structures pp 919ndash924 2004

[35] W Eitel Silicate Science Volume I Silicate Structures AcademicPress New York NY USA 1964

[36] M Y A Mollah W Yu R Schennach and D L CockeldquoFourier transform infrared spectroscopic investigation of theearly hydration of Portland cement and the influence of sodiumlignosulfonaterdquoCement andConcrete Research vol 30 no 2 pp267ndash273 2000

[37] F A Rodrigues ldquoSynthesis of chemically and structurallymodified dicalcium silicaterdquoCement andConcrete Research vol33 no 6 pp 823ndash827 2003

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


120574-C2S 120572998400L-C2S 120572998400H-C2S 120572-C2SOrthorhombic OrthorhombicOrthorhombic Hexagonal

120573-C2SMonoclinic

sim700∘C 1160∘C 1450∘C

60sim80∘C

Figure 1 Polymorphs of belite

Na+ and K+ can replace calcium andor silicon atoms in thestructure and reduce the CaSi ratio of 120573-C

2S to less than 2

[11 12] Reactivity and hydraulic properties of stabilized 120573-C2S depend on the type and amount of the stabilizing ions

[13] On the other hand fast cooling may produce fine 120573-C2S crystals affording 120573-120574-C

2S transformation even without

the need for stabilizer [14] Based on density functionaltheory calculations stabilizing ions modify charge densitylocalization of the electronic structure of C

2S and enhance

the reactivity and in turn would broaden the applicability ofC2S [7]Synthesis of low-energy belite cement as an alternative

to the conventional Portland cement was carried out in twostepsThefirst step is preparation of dicalcium silicate hydrate(hillebrandite Ca

2(SiO3)(OH)

2) by hydrothermal treatment

of silica rich waste materiallime mixtures Hillebrandite wassynthesized by hydrothermal treatment of quartz and limewith CaSi = 20 at 200∘C for 10 hours or at 250∘C for 5hours [15] The main silicate anion structure of hillebranditestudied by 29Si MAS NMR analysis is a mixture of a dimerand a single-chain polymer (larger than Si

5O16) and that

polymerization advancedwith an increase of the synthesizingtemperature [16] Different polymorphs of calcium silicatehydrates with CaSi = 20 namely 120572-C

2SH [Ca

2(SiO4H)OH]

dellaite [Ca6Si3O11(OH)2] and hillebrandite were synthe-

sized and their stability and phase transformation wereinvestigated under hydrothermal conditions up to 400∘C 120572-C2SH completely transforms to dellaite at 350∘C for 1 hour

which in turn undergoes a reversible phase transformationto hillebrandite at low temperatures below 300∘C [17] Hille-brandite was synthesized by mechanochemical treatment ofamorphous precipitated silicalime using a vibration mill atroom temperature [18] The second step involves calcinationof hillebrandite to prepare belite Hillebrandite starts todecompose at about 500∘C producing low-crystalline 120573-C

2S

[15] Moreover 29Si MAS NMR analysis illustrates that thetemperature at which 120573-C

2S begins to form decreases as

the CaSi ratio of hillebrandite becomes higher [19] or asthe temperature of hydrothermal synthesis of hillebranditebecomes higher [16] On the other hand XRD analysisillustrates that the crystallographic properties and density ofdissociation products of 120572-C

2SH depend on the calcination

temperature [20] 120572-C2SH dissociates at 390ndash490∘C forming

an intermediate phase plus 120574-C2S The intermediate phase

then transforms to 1205721015840L phase at 920ndash960∘C and yields 120573-C

2S

on cooling while hillebrandite yields 120573-C2S at the lowest tem-

perature [21] Hillebrandite synthesized bymechanochemicaltreatment of amorphous precipitated silicalime decomposedinto 120573-C

2S below 1000∘C [18]

The reactivity of 120573-C2S relates to its large specific surface

area taking into consideration the fact that the hydration ischemical-reaction-rate-controlled until its completion [19]The specific surface area of 120573-C

2S depends on calcination

temperature of hillebrandite The hydration rate of 120573-C2S

enhanced with increasing surface area The specific surfacearea affects the hydration reaction mechanism In the caseof specific areas of 55m2g or less the reaction changesfrom a chemical reaction to a diffusion-controlled one [22]The hydration rate of 120573-C

2S enhances with raising curing

temperature of hydration [23] The hydration rate of 120573-C2S

enhancedwith dynamicmore than static hydration condition[24] At early ages of hydration 120573-C

2S yields CndashSndashH with

a CaSi ratio of 181 plus Ca(OH)2 At later ages CndashSndashH

and Ca(OH)2react to form a CndashSndashH(II)-like monophase

hydrate having aCaSi ratio of 198with differentmorphology[24] The hydration rate of the 120573-C

2S also enhances with

increasing watersolid ratio [25] Recent works presentedalternative cements containing higher amounts of 120573-C

2S in

their composition based upon the use of waste materialssuch as rice hull and husk ash as well as coal fly ash [15 2627] Silica fume is an abundant material produced in manycountries as a waste product from silicon industry around theworld containing approximately 90ndash97 os SiO

2 Silica fume

have average particle size lt1 120583m specific surface area of 13ndash30m2g and specific gravity of 222 Reuse of waste materialsseems to be a good approach to solve both economic andenvironmental issues related to cement production [28ndash30]This work describes a method for the production of 120573-C

2S

from silica fume

2 Materials and Experimental Techniques

Freshly prepared lime was prepared by calcination of lime-stone powder (purity gt 99) in an electrical muffle furnaceat 950∘C for 3 hours Lime was cooled to room temperaturein desiccator milled and stored in tightly closed plasticbottle to avoid carbonation Silica fume was purchasedfrom Ferrosilicon Company Edfo Egypt Distilled water andanalytical grade barium chloride were used without further

















15 20 25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(a)

(b)

C

C

C C C


0

25

50

75

100

125

150

40080012001600200024002800320036004000

Tran

smitt

ance

()


1101

796

467





4








Weight loss()

Weight loss(mg)



593ndash781 734 196 160


Total 2898 236

1120583m


0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

11011450

1800

2530

3643



0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

1101

1450

1800

2530

3643





2S transformed




2S


2S [13]



2S andor 120574-C

2S after




minus12

minus4

4

12

68

76

84

92

100

0 500 1000

DTA

(120583V

)

TGA

()

Temperature (∘C)

109 422 508

734

955

TGA

DTA

1

2

43


0

10

20

30

40

50

60

70

80

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


3643

1450

1000

910

430530

(c)

(b)

(a)






2S at 734∘C









2S (minor) appears


25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)

PC B BG

C

C C

(a)C

(c)



2S)

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)P

C

C

B BG

CC

C

(a)

C



2S





2S

to 120574-C2S [13]



1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



















15 20 25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(a)

(b)

C

C

C C C


0

25

50

75

100

125

150

40080012001600200024002800320036004000

Tran

smitt

ance

()


1101

796

467





4








Weight loss()

Weight loss(mg)



593ndash781 734 196 160


Total 2898 236

1120583m


0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

11011450

1800

2530

3643



0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

1101

1450

1800

2530

3643





2S transformed




2S


2S [13]



2S andor 120574-C

2S after




minus12

minus4

4

12

68

76

84

92

100

0 500 1000

DTA

(120583V

)

TGA

()

Temperature (∘C)

109 422 508

734

955

TGA

DTA

1

2

43


0

10

20

30

40

50

60

70

80

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


3643

1450

1000

910

430530

(c)

(b)

(a)






2S at 734∘C









2S (minor) appears


25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)

PC B BG

C

C C

(a)C

(c)



2S)

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)P

C

C

B BG

CC

C

(a)

C



2S





2S

to 120574-C2S [13]



1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials









Weight loss()

Weight loss(mg)



593ndash781 734 196 160


Total 2898 236

1120583m


0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

11011450

1800

2530

3643



0

10

20

30

40

50

60

70

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


(b)

(a)

950

700

330

840

1101

1450

1800

2530

3643





2S transformed




2S


2S [13]



2S andor 120574-C

2S after




minus12

minus4

4

12

68

76

84

92

100

0 500 1000

DTA

(120583V

)

TGA

()

Temperature (∘C)

109 422 508

734

955

TGA

DTA

1

2

43


0

10

20

30

40

50

60

70

80

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


3643

1450

1000

910

430530

(c)

(b)

(a)






2S at 734∘C









2S (minor) appears


25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)

PC B BG

C

C C

(a)C

(c)



2S)

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)P

C

C

B BG

CC

C

(a)

C



2S





2S

to 120574-C2S [13]



1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




minus12

minus4

4

12

68

76

84

92

100

0 500 1000

DTA

(120583V

)

TGA

()

Temperature (∘C)

109 422 508

734

955

TGA

DTA

1

2

43


0

10

20

30

40

50

60

70

80

40080012001600200024002800320036004000

Relat

ive t

rans

mitt

ance

()


3643

1450

1000

910

430530

(c)

(b)

(a)






2S at 734∘C









2S (minor) appears


25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)

PC B BG

C

C C

(a)C

(c)



2S)

25 30 35 40 45

Relat

ive i

nten

sity

()

2120579

(b)P

C

C

B BG

CC

C

(a)

C



2S





2S

to 120574-C2S [13]



1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)




2


(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (a 998400)

(b) (b998400)

(c) (c 998400)

(d) (d998400)

1120583m

1120583m

1120583m

1120583m 1120583m

1120583m

1120583m

1120583m



2addition contain







(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (a998400)

(b) (b998400)

(c) (c998400)

(d) (d998400)

1120583m 1120583m

1120583m 1120583m

1120583m1120583m

1120583m 1120583m







4 Conclusions







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







C2S at 955∘C



2S










References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials
























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article low temperature synthesis of belite...

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