Development of Crystallinity of Triclinic Polymorph of Tricalcium Silicate

ma e ials A icle De elopmen o C ys allini y o T iclinic Polymo ph o T icalcium Silica e Simona Ra aszo áand Ka el D oˇ ák * Facul y o Ci il Enginee ing, B no Uni e si y o Technology, Ve eˇ í331/95, 602 00 B no, Czech Republic; [email p o ec ed].cz *Co espondence: [email p o ec ed].cz Recei ed: 30 July 2020; Accep ed: 20 Augus 2020; Published: 24 Augus 2020   Abs ac : T icalcium silica e phase is one o he main componen s o mode n Po land cemen s. One o he majo indus ial challenges in he ield o cemen p oduc ion is mapping he in luence o indi idual clinke mine als and hei polymo phs on he p ope ies o indus ially p oduced clinke s. The p ima y goal o his wo k is o imp o e he undamen al knowledge o unde s anding he p ocess o ali e o ma ion and de elopmen om a c ys allog aphic poin o iew. This s udy ocuses on he obse a ion o he c ys alliza ion p ocess o iclinic ali e du ing he i ing p ocess, which o da e has no been ho oughly desc ibed. The e ec s o a wide ange o empe a u es and sin e ing pe iods on c ys allini y we e assessed on samples i ed in pla inum c ucibles in a labo a o y u nace. X- ay analysis— oge he wi h calcula ion o c ys allini y using Sche e ’s equa ion—was used o obse ing he c ys alli e size changes o T1 ali e polymo ph. Acco ding o he acqui ed esul s, among he mos echnologically and economically ad an ageous egimes o p oduc ion o a high-quali y iclinic ali e is he empe a u e o 1450 ◦ C and sin e ing ime o wo hou s. The mos signi ican changes in he c ys alli e size occu ed wi hin he i s hou o sin e ing o he whole in es iga ed empe a u e ange. Keywo ds: iclinic icalcium silica e; ali e; c ys alli e size; Sche e equa ion; g ow h a e 1. In oduc ion The mode n ends in indus y and comme ce a e owa ds en i onmen al sus ainabili y and economic sa ings. This app oach has led o he de elopmen o nume ous enhancemen s h oughou a ious indus ial b anches— om medicine and bioenginee ing [ 1 ], me allu gy and ma e ials enginee ing [ 2 ], ecycling and eco e y [ 3 ], he mal enginee ing [ 4 ], o ci il enginee ing and cemen indus y [ 5 ]. Resea ch s udies wi hin he la e b anch ha e paid nonnegligible a en ion o sus ainable de elopmen , since—in esponse o long- ime ma ke demands—ali e con en s in Po land cemen s ha e been g adually inc easing. Howe e , he manu ac u e o cemen s wi h highe ali e con en s b ings abou highe en i onmen al impac s. Me hods o educing emissions a e being con inuously de eloped in he cemen indus y, since he p oduc ion p ocess o Po land cemen p oduces signi ican amoun o CO 2 , which is eleased du ing bo h, he he mal decomposi ion o limes one ca bona es and uel combus ion. By his eason, e ined uels a e being g adually subs i u ed by al e na i e uels, which in oduces economic and en i onmen al bene i s, bu b ings abou many echnological issues, oo. These issues o igina e om inc easing he con en s o ce ain elemen s; he e ec s o he changes on he p ope ies o he p oduced clinke s a e subjec o con inuous in es iga ions and moni o ing [ 6 – 11 ]. Ano he possible way how o educe CO 2 emissions is o adjus he aw-meal composi ion o dec ease he clinke i ing empe a u e. Manu ac u ing o cemen s wi h educed en i onmen al impac s would esul in dec easing he o e all en i onmen al oo p in o conc e e as a cons uc ion ma e ial. Ma e ials 2020,13, 3734; doi:10.3390/ma13173734 www.mdpi.com/jou nal/ma e ials Ma e ials 2020,13, 3734 2 o 11 The main con empo a y issue o indus ial p oduc ion o cemen s is he a iabili y o hei mine alogical composi ion, which depends on he p esence o impu i ies (o igina ing om aw ma e ials o uel) and he i ing p ocess. The e o e, he p ocess o syn hesis o clinke mine als is c ucial o de e mina ion o hei subsequen beha io in indus ially p oduced cemen s. In o de o cha ac e ize and possibly in luence he a iabili y o mine alogical composi ion o clinke s, he e ec s o indi idual polymo phso clinke mine alson hep ope ieso indus iallyp oducedclinke s, especially om he iewpoin s o ac ing chemis y and hei in e nal s uc u es, need o be s udied [ 12 – 14 ]. Gene ally, abou wen y indi idual mine als can be iden i ied wi hin clinke s, bu ou o hem a e he mos signi ican . These a e icalcium silica e (C 3 S, ali e), dicalcium silica e (C 2 S, beli e), icalcium alumina e (C 3 A) and e a calcium alumina e e i e (C 4 AF). These ou clinke mine als a e he p ima y ones de e mining he p ope ies o he cemen s ( oge he , hey o m o e 90% o he o al mass o clinke s). Gi en by hei cha ac e is ic p ope ies, each o hese mine als a ec s he p ope ies o he indi idual cemen speci ically. Excep o e a calcium alumina e e i e, all he majo clinke mine als exhibi s ong polymo phism [15]. Mos o he s anda d me hods used o p epa e clinke mine als a e a he ime-consuming; he solid-s a e eac ion and sol–gel me hod a e he mos widely used p ocedu es. The main limi ing and ime-consuming p ocessing s eps/ ac o s du ing p epa a ion o clinke mine als a e disc p essing, demanding sin e ing ime and limi ed capaci y o he used pla inum c ucibles and u naces. The composi ion o he aw ma e ial and he se ing o he i ing pa ame e s a e he p ima y a ec ing ac o s de e mining he inal phase composi ion o he clinke [ 16 , 17 ]. Howe e , ano he impo an ac o in luencing he phase composi ion o he clinke , qui e a negligible a en ion o which has been paid so a , is mechanical–chemical ac i a ion. The possible p esence o ac i e su aces can in luence he p ocess o C 2 S o ma ion du ing he solid-s a e eac ion and consequen ly acili a e he p ocess o C 3 S o ma ion om he mel . By using sui able ac i a ion g inding echnology and by op imizing he milling p ocess, i should be possible o a oid disc p essing, educe he i ing empe a u e and sin e ing ime and p omo e he o ma ion o he desi ed polymo phs [18,19]. The mos impo an clinke mine al is icalcium silica e (C 3 S), which is cha ac e ized by ex ensi e polymo phism; se en s uc u al modi ica ions o C 3 S ha e been iden i ied so a : h ee iclinic (T1, T2, T3), h ee monoclinic (M1, M2, M3) and one igonal (R) [ 15 , 17 ]. The sequence o ali e ans o ma ions is shown in he ollowing Figu e 1[15]: Ma e ials 2020, 13, x FOR PEER REVIEW 2 o 11 The main con empo a y issue o indus ial p oduc ion o cemen s is he a iabili y o hei mine alogical composi ion, which depends on he p esence o impu i ies (o igina ing om aw ma e ials o uel) and he i ing p ocess. The e o e, he p ocess o syn hesis o clinke mine als is c ucial o de e mina ion o hei subsequen beha io in indus ially p oduced cemen s. In o de o cha ac e ize and possibly in luence he a iabili y o mine alogical composi ion o clinke s, he e ec s o indi idual polymo phs o clinke mine als on he p ope ies o indus ially p oduced clinke s, especially om he iewpoin s o ac ing chemis y and hei in e nal s uc u es, need o be s udied [12–14]. Gene ally, abou wen y indi idual mine als can be iden i ied wi hin clinke s, bu ou o hem a e he mos signi ican . These a e icalcium silica e (C3S, ali e), dicalcium silica e (C2S, beli e), icalcium alumina e (C3A) and e a calcium alumina e e i e (C4AF). These ou clinke mine als a e he p ima y ones de e mining he p ope ies o he cemen s ( oge he , hey o m o e 90% o he o al mass o clinke s). Gi en by hei cha ac e is ic p ope ies, each o hese mine als a ec s he p ope ies o he indi idual cemen speci ically. Excep o e a calcium alumina e e i e, all he majo clinke mine als exhibi s ong polymo phism [15]. Mos o he s anda d me hods used o p epa e clinke mine als a e a he ime-consuming; he solid-s a e eac ion and sol–gel me hod a e he mos widely used p ocedu es. The main limi ing and ime-consuming p ocessing s eps/ ac o s du ing p epa a ion o clinke mine als a e disc p essing, demanding sin e ing ime and limi ed capaci y o he used pla inum c ucibles and u naces. The composi ion o he aw ma e ial and he se ing o he i ing pa ame e s a e he p ima y a ec ing ac o s de e mining he inal phase composi ion o he clinke [16,17]. Howe e , ano he impo an ac o in luencing he phase composi ion o he clinke , qui e a negligible a en ion o which has been paid so a , is mechanical–chemical ac i a ion. The possible p esence o ac i e su aces can in luence he p ocess o C2S o ma ion du ing he solid-s a e eac ion and consequen ly acili a e he p ocess o C3S o ma ion om he mel . By using sui able ac i a ion g inding echnology and by op imizing he milling p ocess, i should be possible o a oid disc p essing, educe he i ing empe a u e and sin e ing ime and p omo e he o ma ion o he desi ed polymo phs [18,19]. The mos impo an clinke mine al is icalcium silica e (C3S), which is cha ac e ized by ex ensi e polymo phism; se en s uc u al modi ica ions o C3S ha e been iden i ied so a : h ee iclinic (T1, T2, T3), h ee monoclinic (M1, M2, M3) and one igonal (R) [15,17]. The sequence o ali e ans o ma ions is shown in he ollowing Figu e 1 [15]: Figu e 1. The sequence o ali e ans o ma ions. The i s men ion o polymo phism o he C3S da es back o he ea ly 1950s. Je e y documen ed ha pu e C3S consis s o iclinic (T1) and monoclinic (M3) modi ica ions o ali e and u he de eloped a hypo hesis o he high- empe a u e polymo phic o m wi h igonal s uc u e [20]. The i s sys ema ic wo k on he opic was done by Regou d, Guinie e and hei co-wo ke s [21–23]. Regou d poin ed ou ha each polymo phic ali e o m could be iden i ied a a ce ain angula ange. Subsequen s udy was pe o med by Golo as iko and his eam, who in es iga ed he T1 s uc u e. La e on, wi hin a ew yea s, o he s uc u es we e iden i ied (gi en by he p og ess in he X- ay di ac ion analysis me hods) [24]. The ad ancemen s in equipmen and so wa e led o he in oduc ion o o he ali e s uc u es by Nishi e al. [25], Mumme [26] and Noi on aine [27]. The mos common polymo phs ound in indus ially p oduced clinke s a e M1 and M3; M1 and M3 monoclinic polymo phs we e s udied by Maki e al. [28,29], who poin ed ou he possible in luence o sul a e and magnesium impu i ies on s abiliza ion o he pa icula polymo phs. This opic was also examined by S aněk and Sulo ský [16]. The p ocess o o ma ion and s abili y o he indi idual ali e polymo phs a e he main ac o s in luencing he echnological p ope ies o clinke s. By his eason, s udy o hese ac o s is an impo an issue. This s udy p esen s undamen al esea ch o he basic p ocesses occu ing du ing Figu e 1. The sequence o ali e ans o ma ions. The i s men ion o polymo phism o he C 3 S da es back o he ea ly 1950s. Je e y documen ed ha pu e C 3 S consis s o iclinic (T1) and monoclinic (M3) modi ica ions o ali e and u he de eloped a hypo hesis o he high- empe a u e polymo phic o m wi h igonal s uc u e [ 20 ]. The i s sys ema ic wo k on he opic was done by Regou d, Guinie e and hei co-wo ke s [ 21 – 23 ]. Regou d poin ed ou ha each polymo phic ali e o m could be iden i ied a a ce ain angula ange. Subsequen s udy was pe o med by Golo as iko and his eam, who in es iga ed he T1 s uc u e. La e on, wi hin a ew yea s, o he s uc u es we e iden i ied (gi en by he p og ess in he X- ay di ac ion analysis me hods) [ 24 ]. The ad ancemen s in equipmen and so wa e led o he in oduc ion o o he ali e s uc u es by Nishi e al. [ 25 ], Mumme [ 26 ] and Noi on aine [ 27 ]. The mos common polymo phs ound in indus ially p oduced clinke s a e M1 and M3; M1 and M3 monoclinic polymo phs we e s udied by Maki e al. [ 28 , 29 ], who poin ed ou he possible in luence o sul a e and magnesium impu i ies on s abiliza ion o he pa icula polymo phs. This opic was also examined by S anˇek and Sulo ský[16]. The p ocess o o ma ion and s abili y o he indi idual ali e polymo phs a e he main ac o s in luencing he echnological p ope ies o clinke s. By his eason, s udy o hese ac o s is an impo an Ma e ials 2020,13, 3734 3 o 11 issue. This s udy p esen s undamen al esea ch o he basic p ocesses occu ing du ing he p ocesses o o ma ion and de elopmen o iclinic ali e om a mic oscopic poin o iew. The p esen ed s udy ocuses on moni o ing o he de elopmen o c ys alli e size du ing he i ing p ocess o a T1 polymo ph o ali e; T1–ali e was chosen because i can be ela i ely easily p epa ed by cooling pu e Ca3SiO5compound. 2. Ma e ials and Me hods The p ocess o mechanical ac i a ion wi h high- empe a u e solid-s a e eac ion was used o syn hesize he iclinic ali e. The basic compounds o calcium ca bona e (CaCO 3 , p.a. pu i y, Lach-Ne , Ne a o ice, Czech Republic) and silica (SiO 2 , p.a. pu i y, Lach-Ne , Ne a o ice, Czech Republic) we e dosed in he amoun s co esponding o he mola a io o icalcium silica e componen s (73.6% CaO and 26.3% SiO2), see he Table 1. Table 1. Chemical composi ion, in g, o 100 g o inal T1 C3S p oduc , C:S =3.0 [27]. Componen CaCO3SiO2 Dosage [g] 131.506 26.316 To p epa e he aw meal, he semi-we app oach was applied [ 30 ]. Calcium ca bona e wi h silica oxide in he mola a io o 3:1 we e weighed and mechanically ac i a ed in a plane a y mill (Pul e ise e 6, F i sch, Ida -Obe s ein, Ge many). The wa e /powde a io o 0.8 was used. The olume o he ha dened s eel milling capsule, 25 g inding s eel balls wi h 20 mm in diame e in which we e inse ed, was 0.5 dm 3 . The g inding ime was 20 min, and he g inding speed was 500 pm. The dosage o he aw ma e ial mix u e was 1000 g in o al. The mechanically ac i a ed aw ma e ial mix u e was d ied in a labo a o y d ye (Binde C170, Binde GmbH., Tu lingen, Ge many) a 105 ◦ C o 24 h. Du ing d ying, nodules o 10 mm in diame e o med na u ally om he powde mix u e. The nodules we e dosed di ec ly in o 30-mL pla inum c ucibles p epa ed o he subsequen i ing p ocess. Fo he solid-s a e eac ion p ocedu e, a en icula high- empe a u e kiln (2017S, Clasic CZ s. .o., ˇ Re nice, Czech Republic) wi h Kan hal supe hea ing elemen s was used. The solid-s a e eac ion was ca ied ou a six di e en empe a u es o 1350, 1400, 1450, 1500, 1550 and 1600 ◦ C and six di e en sin e ing pe iods o 0, 1, 2, 3, 4 and 5 h. The hea ing a e was 10 ◦ C/min. A he end o each i ing mode, he c ucibles we e emo ed om he u nace and immedia ely cooled by a s eam o cold ai . The p oduc o his p oduc ion s ep in he o m a block was subsequen ly milled o a powde in a ib a o y disc mill (RS 200, Re sch, Haan, Ge many) a 900 pm o 20 s. The XRD analysis was pe o med wi h a mul i unc ional di ac ome e (XRD, Empy ean, PANaly ical B.V., Almelo, The Ne he lands) wi h Cu anode; K α was used as he adia ion sou ce wi h he pa ame e s o : λ =1.540598 Å, accele a ing ol age 45 kV, beam cu en 40 mA, di ac ion angle 2 θ in he ange om 5 ◦ o 90 ◦ wi h a scan-s ep o 0.01 ◦ . The ICSD da abase ( eleased 2012) was used o quali a i ely analyze he di ac ion pa e ns. HighSco e plus so wa e (3.0e, PANaly ical B.V., Almelo, The Ne he lands) was used o iden i y he indi idual phases, pe o m hei quan i ica ion and de e mine he amoun o he amo phous phase, which was es ima ed using he “cons an backg ound in ensi y” me hod, he c ys allini y o a sample in which is de ined as he in ensi y a io o he di ac ion peaks and o he sum o all he measu ed in ensi ies (can be calcula ed using Equa ion (1)): C= 100 ·PI PI o −PIcons .bg .(1) whe e Cis c ys allini y in %, Iis a ea o c ys alline peaks, I o is o al a ea and I cons .bg . is a ea o cons an backg ound. The cons an backg ound in ensi y is sub ac ed om he o al in ensi y [31]. The size o he c ys alli es was e alua ed on a selec ed di ac ion line a an app op ia ely selec ed c ys allog aphic plane posi ioned in a majo c ys allog aphic di ec ion. We selec ed a high-in ensi y Ma e ials 2020,13, 3734 4 o 11 di ac ion line which co e ed he selec ed plane and, a he same ime, did no o e lap wi h o he di ac ion lines (especially be a C 2 S), de ined by he “hkl” Mille index o 4 4 5. Calcula ion o he size o he c ys alli e was based on he measu emen o FWHM ( ull wid h a hal maximum) and he Sche e equa ion [32] wi h Wa en co ec ion [33] (Equa ion (2)), L= K·λ cosθ.1 β = K·λ cosθ.1 √B2−b2(2) whe e L=c ys alli e size, K=Sche e cons an ( he alue o 0.89 was used), λ =K α1 (wa eleng h o X- ay adia ion), θ =di ac ion angle, B=FWHM ( ull wid h a hal maximum), b=FWHM o he size/s ain s anda d used (lan hanum hexabo ide). The ins umen ex ension was se o he LaB 6 s anda d (lan hanum hexabo ide). LaB 6 is conside ed o be a ully c ys alline ma e ial, he size o he c ys alli es in which is heo e ically equal o in ini y. Peaks o LaB 6 we e de e mined in he posi ions iden ical o he selec ed di ac ion lines in he same way in he HighSco e plus so wa e. The FWHM alues o LaB 6 we e calcula ed om he equa ion depic ed in Figu e 2. O he ac o s a ec ing he accu acy o his e alua ion me hod, such as s ain, we e neglec ed since hey we e no c ucial o he aim o his expe imen — o assess he end o de elopmen o he size o he c ys alli es du ing he i ing p ocess. Ma e ials 2020, 13, x FOR PEER REVIEW 4 o 11 he size o he c ys alli e was based on he measu emen o FWHM ( ull wid h a hal maximum) and he Sche e equa ion [32] wi h Wa en co ec ion [33] (Equa ion (2)), = . cos .1 =. cos .1 √ −  (2) whe e L = c ys alli e size, K = Sche e cons an ( he alue o 0.89 was used), λ = Kα1 (wa eleng h o X- ay adia ion), θ = di ac ion angle, B = FWHM ( ull wid h a hal maximum), b = FWHM o he size/s ain s anda d used (lan hanum hexabo ide). The ins umen ex ension was se o he LaB6 s anda d (lan hanum hexabo ide). LaB6 is conside ed o be a ully c ys alline ma e ial, he size o he c ys alli es in which is heo e ically equal o in ini y. Peaks o LaB6 we e de e mined in he posi ions iden ical o he selec ed di ac ion lines in he same way in he HighSco e plus so wa e. The FWHM alues o LaB6 we e calcula ed om he equa ion depic ed in Figu e 2. O he ac o s a ec ing he accu acy o his e alua ion me hod, such as s ain, we e neglec ed since hey we e no c ucial o he aim o his expe imen — o assess he end o de elopmen o he size o he c ys alli es du ing he i ing p ocess. Figu e 2. Ins umen ex ension o LaB6. 3. Resul s Quali a i e moni o ing o he mine alogical composi ion was pe o med by X- ay analysis. Beside T1– icalcium silica e, esidual dicalcium silica e (be a C2S) (ICSD 98-007-9552), ee lime ( - CaO) (ICSD 98-006-0704) and po landi e (Ca(OH)2) (ICSD 98-005-3989) we e iden i ied on he X- ay scans. The amoun o Ca(OH)2 was con e ed o ee CaO by he loss on igni ion me hod; subsequen ecalcula ion o he con en s o indi idual mine als ollowed. The dependence o he con en s o mine als on he empe a u e and sin e ing pe iod is shown in Table 2 and g aphically in Figu e 3. Table 2. Summa y o mine al composi ion de ec ed using Rie eld me hod. Tempe a u e (°C) Sin e ing Pe iod (h) T1–C3S (%) β-C2S (%) -CaO (%) 1350 0 9.12 69.45 21.43 1350 1 68.08 24.28 7.66 1350 2 80.97 14.35 4.68 1350 3 84.36 11.91 3.73 1350 4 86.71 9.68 3.61 1350 5 89.37 7.76 2.87 1400 0 44.45 41.13 14.42 1400 1 83.27 12.36 4.37 1400 2 96.06 0.10 3.80 1400 3 95.81 2.01 2.18 1400 4 98.77 0.30 0.93 Figu e 2. Ins umen ex ension o LaB6. 3. Resul s Quali a i e moni o ing o he mine alogical composi ion was pe o med by X- ay analysis. Beside T1– icalcium silica e, esidual dicalcium silica e (be a C 2 S) (ICSD 98-007-9552), ee lime ( -CaO) (ICSD 98-006-0704) and po landi e (Ca(OH) 2 ) (ICSD 98-005-3989) we e iden i ied on he X- ay scans. The amoun o Ca(OH) 2 was con e ed o ee CaO by he loss on igni ion me hod; subsequen ecalcula ion o he con en s o indi idual mine als ollowed. The dependence o he con en s o mine als on he empe a u e and sin e ing pe iod is shown in Table 2and g aphically in Figu e 3. The obse ed and calcula ed amoun o he amo phous phase was less han 1–2% in all samples. Based on he esul s o he X- ay analysis, he ollowing s a emen s can be done. Wi h inc easing i ing empe a u e, he amoun o iclinic ali e inc eases linea ly om 9.1% a 1350 ◦ C, o 99.4% a 1600 ◦ C. Iden ical phenomenon was obse ed o he inc eased sin e ing pe iods a he indi idual empe a u es. The mos signi ican ime-dependen di e ence in he con en o ali e was obse ed a he lowes empe a u e o 1350 ◦ C; a e 5 h o sin e ing, he con en o ali e inc eased om 9% o 90%. The highe was he i ing empe a u e, he smalle was he obse ed di e ence in he con en o ali e be ween he indi idual sin e ing pe iods. A he empe a u e o 1350 ◦ C, he con en o iclinic ali e was app oxima ely 89% a e 5 h o sin e ing. Simila amoun s o ali e we e achie ed a e he sin e ing pe iods o 2 o 1 h o he highe Ma e ials 2020,13, 3734 5 o 11 empe a u es o 1400 ◦ C and 1450 ◦ C. Since he aim o he s udy was o acqui e he highes possible amoun o ali e a he lowes possible empe a u e and sin e ing ime pe iod, he empe a u e o 1350 ◦ C appea s o be insu icien . The highes ali e con en s o 99.1%, 99.6% and 99.4% we e acqui ed a he ollowing h ee empe a u es (and co esponding sin e ing ime pe iods), espec i ely: 1450 ◦ C (2 h), 1500 ◦ C (4 h) and 1600 ◦ C (5 h). The beli e con en s we e equal o 0%, and he amoun s o ee lime we e negligible (<1%). The e o e, he empe a u e o 1450 ◦ C and 2 h o sin e ing seems o be he ideal i ing egime om he iewpoin o easonable sin e ing ime and economic complexi y. Table 2. Summa y o mine al composi ion de ec ed using Rie eld me hod. Tempe a u e (◦C) Sin e ing Pe iod (h) T1–C3S (%) β-C2S (%) -CaO (%) 1350 0 9.12 69.45 21.43 1350 1 68.08 24.28 7.66 1350 2 80.97 14.35 4.68 1350 3 84.36 11.91 3.73 1350 4 86.71 9.68 3.61 1350 5 89.37 7.76 2.87 1400 0 44.45 41.13 14.42 1400 1 83.27 12.36 4.37 1400 2 96.06 0.10 3.80 1400 3 95.81 2.01 2.18 1400 4 98.77 0.30 0.93 1400 5 97.06 1.50 1.44 1450 0 64.75 26.58 8.67 1450 1 91.60 6.14 2.26 1450 2 99.14 0.00 0.86 1450 3 98.80 0.50 0.70 1450 4 98.85 0.60 0.55 1450 5 98.65 0.40 0.95 1500 0 75.80 16.37 7.84 1500 1 98.89 0.00 1.11 1500 2 98.32 0.90 0.78 1500 3 99.35 0.00 0.65 1500 4 99.55 0.00 0.45 1500 5 99.45 0.00 0.55 1550 0 82.65 12.78 4.58 1550 1 98.34 0.80 0.86 1550 2 99.32 0.00 0.68 1550 3 99.00 0.40 0.60 1550 4 99.14 0.00 0.86 1550 5 99.22 0.00 0.78 1600 0 89.22 8.57 2.21 1600 1 99.22 0.00 0.78 1600 2 99.02 0.80 0.18 1600 3 98.92 0.30 0.78 1600 4 99.07 0.40 0.53 1600 5 99.37 0.00 0.63 Ma e ials 2020,13, 3734 6 o 11 Ma e ials 2020, 13, x FOR PEER REVIEW 5 o 11 1400 5 97.06 1.50 1.44 1450 0 64.75 26.58 8.67 1450 1 91.60 6.14 2.26 1450 2 99.14 0.00 0.86 1450 3 98.80 0.50 0.70 1450 4 98.85 0.60 0.55 1450 5 98.65 0.40 0.95 1500 0 75.80 16.37 7.84 1500 1 98.89 0.00 1.11 1500 2 98.32 0.90 0.78 1500 3 99.35 0.00 0.65 1500 4 99.55 0.00 0.45 1500 5 99.45 0.00 0.55 1550 0 82.65 12.78 4.58 1550 1 98.34 0.80 0.86 1550 2 99.32 0.00 0.68 1550 3 99.00 0.40 0.60 1550 4 99.14 0.00 0.86 1550 5 99.22 0.00 0.78 1600 0 89.22 8.57 2.21 1600 1 99.22 0.00 0.78 1600 2 99.02 0.80 0.18 1600 3 98.92 0.30 0.78 1600 4 99.07 0.40 0.53 1600 5 99.37 0.00 0.63 Figu e 3. G aphic ep esen a ion o change in mine al composi ion wi h inc easing sin e ing pe iod. (a) T1–C3S con en ; (b) β-C2S con en ; (c) -CaO con en ; (d) linea dependence o he amoun o T1– C3S on inc easing empe a u e. Figu e 3. G aphic ep esen a ion o change in mine al composi ion wi h inc easing sin e ing pe iod. ( a ) T1–C 3 S con en ; ( b ) β -C 2 S con en ; ( c ) -CaO con en ; ( d ) linea dependence o he amoun o T1–C 3 S on inc easing empe a u e. Due o he complexi y o he c ys al la ice o iclinic ali e, a c ys allog aphic plane cha ac e ized wi h a dominan c ys allog aphic di ec ion, and, a he same ime, mani es ing in he di ac ion eco d wi h a signi ican isola ed peak (wi hou o e lapping wi h he beli e line) was chosen. The c ys allog aphic plane 4 4 5 is mani es ed in he di ac ion pa e n by a peak a he 2 θ angle o 34.291◦, see Figu e 4. Ma e ials 2020, 13, x FOR PEER REVIEW 6 o 11 The obse ed and calcula ed amoun o he amo phous phase was less han 1–2% in all samples. Based on he esul s o he X- ay analysis, he ollowing s a emen s can be done. Wi h inc easing i ing empe a u e, he amoun o iclinic ali e inc eases linea ly om 9.1% a 1350 °C, o 99.4% a 1600 °C. Iden ical phenomenon was obse ed o he inc eased sin e ing pe iods a he indi idual empe a u es. The mos signi ican ime-dependen di e ence in he con en o ali e was obse ed a he lowes empe a u e o 1350 °C; a e 5 h o sin e ing, he con en o ali e inc eased om 9% o 90%. The highe was he i ing empe a u e, he smalle was he obse ed di e ence in he con en o ali e be ween he indi idual sin e ing pe iods. A he empe a u e o 1350 °C, he con en o iclinic ali e was app oxima ely 89% a e 5 h o sin e ing. Simila amoun s o ali e we e achie ed a e he sin e ing pe iods o 2 o 1 h o he highe empe a u es o 1400 °C and 1450 °C. Since he aim o he s udy was o acqui e he highes possible amoun o ali e a he lowes possible empe a u e and sin e ing ime pe iod, he empe a u e o 1350 °C appea s o be insu icien . The highes ali e con en s o 99.1%, 99.6% and 99.4% we e acqui ed a he ollowing h ee empe a u es (and co esponding sin e ing ime pe iods), espec i ely: 1450 °C (2 h), 1500 °C (4 h) and 1600 °C (5 h). The beli e con en s we e equal o 0%, and he amoun s o ee lime we e negligible (<1%). The e o e, he empe a u e o 1450 °C and 2 h o sin e ing seems o be he ideal i ing egime om he iewpoin o easonable sin e ing ime and economic complexi y. Due o he complexi y o he c ys al la ice o iclinic ali e, a c ys allog aphic plane cha ac e ized wi h a dominan c ys allog aphic di ec ion, and, a he same ime, mani es ing in he di ac ion eco d wi h a signi ican isola ed peak (wi hou o e lapping wi h he beli e line) was chosen. The c ys allog aphic plane 44 5 is mani es ed in he di ac ion pa e n by a peak a he 2θ angle o 34.291°, see Figu e 4. Figu e 4. De ail o selec ed c ys allog aphic plane 44 5 on X- ay pa e n. Sche e ’s equa ion was used o moni o he dependence o c ys alli e size on he empe a u e and sin e ing ime pe iod on he 44 5 c ys allog aphic plane; see Table 3 o he alues o sizes o he c ys alli es and Figu e 5a–d o g aphic p esen a ion. Based on he de elopmen o c ys allini y du ing he i ing egimes, he g ow h a e o c ys alli es was e alua ed when he indi idual empe a u es we e eached, see Table 4. Table 3. C ys alli e size in he plane 44 5. Tempe a u e [°C] C ys alli e Size [nm] 0 h 1 h 2 h 3 h 4 h 5 h 1350 33.391 52.239 53.813 55.128 54.793 51.371 1450 37.018 53.813 52.159 51.960 51.99 51.693 1450 47.562 52.259 51.693 50.263 49.652 49.652 1500 51.054 52.835 49.714 49.177 50.542 49.177 1550 51.342 52.593 49.177 49.987 48.652 47.886 1600 49.417 47.886 48.913 48.394 50.144 51.156 Figu e 4. De ail o selec ed c ys allog aphic plane 445 on X- ay pa e n. Sche e ’s equa ion was used o moni o he dependence o c ys alli e size on he empe a u e and sin e ing ime pe iod on he 4 4 5 c ys allog aphic plane; see Table 3 o he alues o sizes o he c ys alli es and Figu e 5a–d o g aphic p esen a ion. Based on he de elopmen o c ys allini y du ing he i ing egimes, he g ow h a e o c ys alli es was e alua ed when he indi idual empe a u es we e eached, see Table 4. Ma e ials 2020,13, 3734 7 o 11 Table 3. C ys alli e size in he plane 445. Tempe a u e [◦C] C ys alli e Size [nm] 0 h 1 h 2 h 3 h 4 h 5 h 1350 33.391 52.239 53.813 55.128 54.793 51.371 1450 37.018 53.813 52.159 51.960 51.99 51.693 1450 47.562 52.259 51.693 50.263 49.652 49.652 1500 51.054 52.835 49.714 49.177 50.542 49.177 1550 51.342 52.593 49.177 49.987 48.652 47.886 1600 49.417 47.886 48.913 48.394 50.144 51.156 Ma e ials 2020, 13, x FOR PEER REVIEW 7 o 11 (a) (b) (c) (d) Figu e 5. De elopmen o c ys allini y. (a) In luence o empe a u e on c ys alli e size a 1 h o sin e ing; (b) in luence o sin e ing pe iod on c ys alli e size a 1450 °C; (c) 3D g aph o g ow h o c ys alli es in plane 44 5; (d) de ail o 3D g aph o g ow h o c ys alli es in plane 44 5. Table 4. G ow h a e o c ys alli e size. Tempe a u e (°C) G ow h Ra e (nm/min) 0–1 h 1–2 h 2–3 h 3–4 h 4–5 h 1350 0.88 0.90 0.92 0.91 0.64 1400 0.97 0.95 0.94 0.95 0.69 1450 1.05 1.03 1.01 0.97 0.70 1500 1.11 1.10 1.09 1.12 0.76 1550 1.31 1.23 1.25 1.22 0.80 1600 1.37 1.40 1.38 1.41 0.90 As can be seen in Figu e 5, wi h inc easing empe a u e, he in ensi y o he di ac ion lines inc eased, and he shapes o he di ac ion lines became na owe and longe . Simila inc ease in in ensi y was obse ed o a single sin e ing empe a u e (speci ically 1450 °C), howe e , wi h inc easing sin e ing ime pe iod (Figu e 5b). The mos signi ican changes in c ys allini y occu ed wi hin 1, possibly 2, hou s o sin e ing, when icalcium ali e is s ill o ming . This phenomenon is he mos e iden in he de ailed sec ion o he g aph depic ed in Figu e 5d; as can be seen, s eady inc ease in he c ys alli e size occu ed wi h inc easing empe a u e up o 1 h o sin e ing (see Figu e 5c,d). A e 1 h o sin e ing, he c ys alli e size emained mo e o less cons an . As ega ds he g ow h a e o he c ys alli es, he highes a e o c ys alli e o ma ion was obse ed wi hin jus 1 h. In addi ion, he highe was he empe a u e, he as e was he c ys alli e g ow h a e. A e 1 o 2 h o sin e ing, he g ow h a e dec eased, and he c ys alli e size was mo e o less cons an . 4. Discussion The p esen s udy deals wi h moni o ing o he c ys alliza ion p ocess o iclinic ali e du ing he i ing p ocess. The pa ame e s o p epa a ion o he aw ma e ial we e op imized o maximize he amoun o ali e in he sample while main aining easonable p ocessing ime. T iclinic ali e was Figu e 5. De elopmen o c ys allini y. ( a ) In luence o empe a u e on c ys alli e size a 1 h o sin e ing; ( b ) in luence o sin e ing pe iod on c ys alli e size a 1450 ◦ C; ( c ) 3D g aph o g ow h o c ys alli es in plane 445; (d) de ail o 3D g aph o g ow h o c ys alli es in plane 445. Table 4. G ow h a e o c ys alli e size. Tempe a u e (◦C) G ow h Ra e (nm/min) 0–1 h 1–2 h 2–3 h 3–4 h 4–5 h 1350 0.88 0.90 0.92 0.91 0.64 1400 0.97 0.95 0.94 0.95 0.69 1450 1.05 1.03 1.01 0.97 0.70 1500 1.11 1.10 1.09 1.12 0.76 1550 1.31 1.23 1.25 1.22 0.80 1600 1.37 1.40 1.38 1.41 0.90 As can be seen in Figu e 5, wi h inc easing empe a u e, he in ensi y o he di ac ion lines inc eased, and he shapes o he di ac ion lines became na owe and longe . Simila inc ease in in ensi ywasobse ed o asinglesin e ing empe a u e(speci ically1450 ◦ C),howe e , wi hinc easing sin e ing ime pe iod (Figu e 5b). The mos signi ican changes in c ys allini y occu ed wi hin 1, possibly 2, hou s o sin e ing, when icalcium ali e is s ill o ming. This phenomenon is he mos e iden in he de ailed sec ion o he g aph depic ed in Figu e 5d; as can be seen, s eady inc ease in he c ys alli e size occu ed wi h inc easing empe a u e up o 1 h o sin e ing (see Figu e 5c,d). A e 1 h o sin e ing, he c ys alli e size emained mo e o less cons an . Ma e ials 2020,13, 3734 8 o 11 As ega ds he g ow h a e o he c ys alli es, he highes a e o c ys alli e o ma ion was obse ed wi hin jus 1 h. In addi ion, he highe was he empe a u e, he as e was he c ys alli e g ow h a e. A e 1 o 2 h o sin e ing, he g ow h a e dec eased, and he c ys alli e size was mo e o less cons an . 4. Discussion The p esen s udy deals wi h moni o ing o he c ys alliza ion p ocess o iclinic ali e du ing he i ing p ocess. The pa ame e s o p epa a ion o he aw ma e ial we e op imized o maximize he amoun o ali e in he sample while main aining easonable p ocessing ime. T iclinic ali e was p oduced by mechanical ac i a ion o a mix u e o he aw ma e ial in a high-ene gy mill in a wa e en i onmen . Du ing d ying o he ma e ial g ound in he wa e en i onmen , he slu y had a endency o agglome a e o solid nodules ( his me hod o p epa a ion was designed acco ding o he semi-d y me hod o p epa a ion o aw meal used in he clinke indus y). This simpli ies he echnological p ocess o p epa a ion wi hou disc p essing, which is he mos common way o p epa ing he ma e ial o he solid-s a e eac ion p ocedu e. Selec ing a sui able composi ion o he mix u e o he aw ma e ial subjec ed o high-ene gy milling enabled p epa a ion o a high-quali y iclinic ali e in he en i e ange o selec ed empe a u es and sin e ing pe iods, as demons a ed in Table 2. Wi h inc easing i ing empe a u e and sin e ing pe iod, he amoun o ali e inc eased— ela i e o o he mine als—as demons a ed in Figu e 3a,c. T aces o po landi e we e iden i ied in all he samples; he p esence o his mine al in he samples o igina ed om apid hyd a ion o un eac ed ee lime while wai ing o being analyzed by he X- ay di ac ome e . Samples i ed o a sho ime pe iods (0–30 min) con ained high amoun s o ee lime, which ended o quickly hyd a e wi h ai humidi y o o m po landi e. Since po landi e is a p oduc o CaO only, his is a e y as eac ion. We u he pe o med ecalcula ion o he eal amoun o ee lime in he samples by he loss o wa e molecule o he po landi e and inc eased he amoun s o he emaining mine als by his alue. The esul s showed ha all he aw ma e ials eac ed o he c ys alline phase when he empe a u e o 1350 ◦ C was eached. The empe a u e o 1350 ◦ C is su icien o all he componen s o occu in he c ys alline o m (ali e, beli e, lime, e c.), because he amoun o he amo phous phase was lowe han 1–2% in all cases. The e o e, we can s a e ha he con en s o indi idual mine als in he samples a e no a ec ed by he amo phous con en . High-quali y T1 ali e (99.1% C 3 S, 0.9% CaO) was acqui ed a 1450 ◦ C and wo hou s o sin e ing, see Table 2. The Sche e me hod was used o assess he e ec s o he i ing p ocess on he de elopmen o he size o he c ys alli es o iclinic ali e. This me hod was chosen due o he complexi y o he iclinic s uc u e, di icul y o i and signi ican peak o e lapping o he indi idual c ys allog aphic planes—especially wi h be a beli e. Gene ally, he mos signi ican changes in he c ys alli e size occu ed wi hin one, possibly wo hou s o sin e ing o he whole empe a u e ange, as shown in Figu e 5a,d. Wi h inc easing i ing empe a u e, he size o he c ys alli es inc eased con inuously. While a he empe a u e o 1350 ◦ C he size o he c ys alli es was 33 nm, a he empe a u e o 1550 ◦ C he size o he c ys alli es was 51 nm, see Table 3. Wi h he inc ease in he sin e ing pe iod o one hou , he size o he c ys alli es inc eased a all he empe a u es. The highe he empe a u e, he smalle he di e ence in he c ys alli e size. We conside ha he ime o one hou o sin e ing is c i ical. The a e age alue o he size o he c ys alli es a his ime was a ound 52 nm, which is 95% o he maximum size. A e one hou s, we no longe obse ed signi ican changes; he size o he c ys alli es was cons an ly a ound 50 nm, see Table 3. The g ow h a e o c ys alli es had a linea end, as depic ed in Figu e 6. As he i ing empe a u e inc eased, he c ys alli es g ew as e . A 1350 ◦ C, he g ow h a e was 0.88 nm/min, a 1600 ◦ C i was as high as 1.37 nm/min, as seen in Table 4. This ac could be explained by he di e en concen a ions o he c ys alliza ion nuclei, which a e highe a highe empe a u es. P olonging he sin e ing ime pe iod a he indi idual empe a u e esul ed in a sligh dec ease in he c ys alli es g ow h a e, which can be a ibu ed o he ac ha he size o he c ys alli es did no signi ican ly change a e one (o wo) hou s o sin e ing. Ma e ials 2020,13, 3734 9 o 11 Ma e ials 2020, 13, x FOR PEER REVIEW 9 o 11 Figu e 6. In luence o sin e ing pe iod on c ys alli e size a in es iga ed empe a u es. 5. Conclusions The main aim o his wo k was o desc ibe he de elopmen o he c ys alliza ion p ocess o iclinic icalcium silica e. Based on he acqui ed esul s, he ollowing can be s a ed:  T iclinic ali e manu ac u ed a 1350 °C is o insu icien quali y;  The mos signi ican changes in he c ys alli e size occu ed du ing 1, possibly 2, hou s o sin e ing wi hin he whole in es iga ed empe a u e ange;  The a e age alue o he c ys alli e size a his sin e ing ime is a ound 52 nm, which is 95% o he maximum size;  A e one hou s, he size o he c ys alli es se led a ound 50 nm, and no signi ican changes we e u he obse ed;  The g ow h a e o c ys alli es has a linea end; as he i ing empe a u e inc eases, he c ys alli es g ow as e ;  The i ing egime o 1450 °C, wo hou s o sin e ing and 1.03 nm/min g ow h a e seems o be ideal om he iewpoin o ime and economic complexi y. The ac ha he undamen al na u e o his esea ch belongs o he Basic Resea ch needs o be emphasized. The goal o he p ojec is o p o ide new knowledge, in o ma ion and connec ions ela ed o unde s anding he o ma ion and de elopmen o indi idual clinke mine als om a mic oscopic poin o iew. The s udy o he o igin, s abili y, and p ope ies o a ious calcium silica e polymo phs is impo an o be e unde s and he p ocesses in ol ed in he p oduc ion o Po land clinke . Newly a ailable echnologies can con ibu e o educ ion in he ene gy consump ion o i ing and educe CO 2 emissions. A he same ime, he syn he ic pu e clinke phases can be subjec o u he in es iga ions (hyd a ion p ocess, e ec s o plas icize s, e c.). Au ho Con ibu ions: Concep ualiza ion, S.R. and K.D.; me hodology, S.R. and K.D.; so wa e, K.D.; alida ion, S.R.; o mal analysis S.R.; in es iga ion, S.R. and K.D.; esou ces K.D.; da a cu a ion, S.R. and K.D.; w i ing— o iginal d a p epa a ion, S.R.; w i ing— e iew and edi ing, S.R.; isualiza ion, S.R.; supe ision, S.R. and K.D.; p ojec adminis a ion, S.R. and K.D.; unding acquisi ion, K.D. and S.R. All au ho s ha e ead and ag eed o he published e sion o he manusc ip . Funding: We acknowledge he inancial suppo o p ojec “S udy o labo a o y p epa a ion, s uc u e and s abili y o icalcium silica e” (FAST-J-20-6257) and p ojec “E ec s o mechano-chemical ac i a ion on he p ocess o o ma ion, s uc u e and s abili y o selec ed clinke mine als” (20-00676S). Con lic s o In e es : The au ho s decla e no con lic s o in e es . Re e ences Figu e 6. In luence o sin e ing pe iod on c ys alli e size a in es iga ed empe a u es. T iclinic ali e was p epa ed wi hin he en i e in es iga ed empe a u e ange and a all he sin e ing ime pe iods. Wi hin he echnologically and economically mos ad an ageous a ian s o p oduc ion o a high-quali y iclinic ali e is he empe a u e o 1450 ◦ C wi h wo hou s o sin e ing, he size o he c ys alli es a which eaches he alue o 52 nm and he g ow h a e is a ound he alue o 1.03 nm/min. 5. Conclusions The main aim o his wo k was o desc ibe he de elopmen o he c ys alliza ion p ocess o iclinic icalcium silica e. Based on he acqui ed esul s, he ollowing can be s a ed: T iclinic ali e manu ac u ed a 1350 ◦C is o insu icien quali y;  The mos signi ican changes in he c ys alli e size occu ed du ing 1, possibly 2, hou s o sin e ing wi hin he whole in es iga ed empe a u e ange;  The a e age alue o he c ys alli e size a his sin e ing ime is a ound 52 nm, which is 95% o he maximum size;  A e one hou s, he size o he c ys alli es se led a ound 50 nm, and no signi ican changes we e u he obse ed;  The g ow h a e o c ys alli es has a linea end; as he i ing empe a u e inc eases, he c ys alli es g ow as e ;  The i ing egime o 1450 ◦ C, wo hou s o sin e ing and 1.03 nm/min g ow h a e seems o be ideal om he iewpoin o ime and economic complexi y. The ac ha he undamen al na u e o his esea ch belongs o he Basic Resea ch needs o be emphasized. The goal o he p ojec is o p o ide new knowledge, in o ma ion and connec ions ela ed o unde s anding he o ma ion and de elopmen o indi idual clinke mine als om a mic oscopic poin o iew. The s udy o he o igin, s abili y, and p ope ies o a ious calcium silica e polymo phs is impo an o be e unde s and he p ocesses in ol ed in he p oduc ion o Po land clinke . Newly a ailable echnologies can con ibu e o educ ion in he ene gy consump ion o i ing and educe CO 2 emissions. A he same ime, he syn he ic pu e clinke phases can be subjec o u he in es iga ions (hyd a ion p ocess, e ec s o plas icize s, e c.). Au ho Con ibu ions: Concep ualiza ion, S.R. and K.D.; me hodology, S.R. and K.D.; so wa e, K.D.; alida ion, S.R.; o malanalysisS.R.; in es iga ion, S.R.andK.D.; esou cesK.D.; da acu a ion, S.R.andK.D.; w i ing—o iginal d a p epa a ion, S.R.; w i ing— e iew and edi ing, S.R.; isualiza ion, S.R.; supe ision, S.R. and K.D.; p ojec adminis a ion, S.R. and K.D.; unding acquisi ion, K.D. and S.R. All au ho s ha e ead and ag eed o he published e sion o he manusc ip .