Politeknik Dergisi 2147-9429 Gazi Üniversitesi 10.2339/politeknik.1746156 Materials Science and Technologies Chemical Engineering (Other) Material Characterization Malzeme Bilimi ve Teknolojileri Kimya Mühendisliği (Diğer) Malzeme Karekterizasyonu Hidrotermal Olarak Sentezlenen Xonotlit ve Tobermorit Ara Fazlarının Isı Yalıtkanı Olarak Wollastonit Oluşumu Üzerindeki Etkileri Effects of Hydrothermally Synthesized Xonotlite and Tobermorite Intermediate Phases on Wollastonite Formation for Thermal Insulator https://orcid.org/0000-0001-8768-2902 Açıl Gülce GAZİ ÜNİVERSİTESİ https://orcid.org/0000-0003-0093-843X Balcı Suna GAZİ ÜNİVERSİTESİ https://orcid.org/0000-0001-6983-0772 Çinici Hanifi GAZİ ÜNİVERSİTESİ 04 21 2026 29 4 1 15 07 19 2025 10 21 2025 Copyright © 1998, Politeknik Dergisi 1998 Politeknik Dergisi

Hidrotermal yöntemle farklı Ca/Si oranları, su/katı (w/s) oranı, reaksiyon sıcaklığı ve sürelerinde sentezlenen tobermorit ve xonotlit kalsiyum silikat hidrat ara fazlarının 800 oC’de kalsinasyonu ile oluşturulan wollastonit fazı üzerine etkileri detaylı şekilde araştırılmıştır. TGA-DTA sonuçları, 200 oC’de sentezlenen malzemelerin daha düşük kütle kaybı ve β-wollastonit oluşumunu temsil eden keskin egzotermik pikler ile daha verimli nihai faza dönüşümü sağlayacağını ortaya koymuştur. FTIR analizleri, 200 oC’de xonotlit benzeri düzenli kristal yapılar, 150 oC’de ise tobermorit benzeri amorf fazların oluştuğunu göstermiştir. Uzun reaksiyon süreleri, amorf C–S–H birikimini artırarak ara fazların kristal kalitesini olumsuz etkilemiştir. Artan w/s oranı iyon taşınımını ve silikat çözünürlüğünü artırarak xonotlit oluşumunu desteklemiştir. Sıcaklık, Ca/Si ve w/s oranlarının kontrollü seçiminin, kristal öncül faz oluşumunda, ardından wollastonite dönüşümünde kritik rol oynadığı görülmüştür. 900 oC’de α-wollastonit faz oluşumu söz konusu olmakla birlikte, wollastonit yapının 1100 oC’ye kadar termal kararlılığını koruduğu belirlenmiştir.

The effects of calcium silicate hydrate intermediate phases tobermorite and xonotlite synthesized hydrothermally under varying Ca/Si ratios, water/solid (w/s) ratios, reaction temperatures, and durations on the wollastonite formation through calcination at 800  oC were investigated in detail. TGA-DTA results revealed that materials synthesized at 200  oC exhibited lower weight losses and sharper exothermic peaks indicative of β-wollastonite formation, suggesting a more efficient transformation into the final phase. FTIR analyses demonstrated that well-ordered xonotlite-like crystalline structures were formed at 200 oC, whereas tobermorite-like phases were observed at 150 oC. Prolonged reaction times were found to increase the accumulation of amorphous C–S–H, thereby adversely affecting crystallinity of the intermediate phases. Higher w/s ratios enhanced ionic transport and silicate solubility, thereby promoting the formation of xonotlite. The controlled selection of temperature, Ca/Si ratio, and w/s ratio was determined to be a key factor in the formation of crystalline precursor phases and their subsequent transformation into wollastonite. Although α-wollastonite formation was detected at 900  oC, the wollastonite structure was found to retain its thermal stability up to 1100  oC.

 Kalsiyum silikatlar Ara fazlar Termal davranış Yalıtım malzemeleri kimyasal yapı Calcium silicates intermediate phases thermal behavior insulation materials chemical structure [1] E. Feyzullahoğlu, M. Korku, R. İlhan, "Farklı Türlerde Polyester ve Çekme Katkısı İçeren Cam Elyaf Takviyeli Polyester Kompozit Malzemelerde Çevresel Koşulların Aşınma Davranışlarına Olan Etkilerinin İncelenmesi", Politeknik Dergisi, 27: 197-209, (2024). [2] M. Torman Kayalar, G. Erdoğan, A. Yavaş, S. Güler, M. Sütçü, "Fabrication of Porous Anorthite Ceramics Using Eggshell Waste as a Calcium Source and Expanded Polystyrene Granules", Politeknik Dergisi, 25: 1235-1241, (2022). [3] IndustryARC., Building insulation market report. (2024). [4] M.R. Future. Global glass wool insulation market trends and forecast to 2034., (2025). [5] G.V. Research. Global stone wool segment market analysis and forecast in oil and gas insulation., (2024). [6] N.V. Gama, A. Ferreira, A. Barros-Timmons, "Polyurethane Foams: Past, Present, and Future", Materials, 11: (2018). [7] Z. Wang, C. Wang, Y. Gao, Z. Li, Y. Shang, H. Li, "Porous Thermal Insulation Polyurethane Foam Materials", Polymers, 15: (2023). [8] Muhammed Raji, H.U. Hambali, Z.I. Khan, Z. Binti Mohamad, H. Azman, R. Ogabi, "Emerging trends in flame retardancy of rigid polyurethane foam and its composites: A review", Journal of Cellular Plastics, 59: 65-122, (2023). [9] R. Volk, J.J. Steins, O. Kreft, F. Schultmann, "Life cycle assessment of post-demolition autoclaved aerated concrete (AAC) recycling options", Resources, Conservation and Recycling, 188: 106716, (2023). [10] F.F. Azmodeh, A. Attar, M. Maniat, M. Rahmati, R. Bahmani, "Comparative Analysis of Autoclaved Aerated Concrete (AAC) vs. Traditional Building Materials for Energy-Efficient Green Building", Journal of Technology Innovations and Energy, 3: 1-12, (2024). [11] K. Sherin, J. Saurabh, An overview of advantages and disadvantages of autoclaved aerated concrete, Proceedings on the National Conference of Advanced Structures, Materials and Methodology in Civil Engineering, ASMMCE-2018, pp. 35-39., (2018). [12] F.H.G. Leite, T.F. Almeida, R.T. Faria, J.N.F. Holanda, "Synthesis and characterization of calcium silicate insulating material using avian eggshell waste", Ceramics International, 43: 4674-4679, (2017). [13] H.-P. Ebert, F. Hemberger, "Intercomparison of thermal conductivity measurements on a calcium silicate insulation material", International journal of thermal sciences, 50: 1838-1844, (2011). [14] T. Almeida, F. Leite, R. Faria, J. Holanda, "Thermal study of calcium silicate material synthesized with solid wastes", Journal of Thermal Analysis and Calorimetry, 128: 1265-1272, (2017). [15] E. Aydın, "Use of Various Industrial and Eggshell Wastes for the Sustainable Construction Sector", Politeknik Dergisi, 27: 1293-1304, (2024). [16] Carrasco-Hurtado, F.A. Corpas-Iglesias, N. Cruz-Pérez, J. Terrados-Cepeda, L. Pérez-Villarejo, "Addition of bottom ash from biomass in calcium silicate masonry units for use as construction material with thermal insulating properties", Construction and Building Materials, 52: 155-165, (2014). [17] E. Steau, M. Mahendran, "Elevated temperature thermal properties of fire protective boards and insulation materials for light steel frame systems", Journal of Building Engineering, 43: 102571, (2021). [18] R. Levinskas, I. Lukošiūtė, A. Baltušnikas, A. Kuoga, A. Luobikienė, J. Rodriguez, I. Cañadas, W. Brostow, "Modified xonotlite–type calcium silicate hydrate slabs for fire doors", Journal of fire sciences, 36: 83-96, (2018). [19] R. Shamsudin, H. Ismail, M. Hamid, R. Awang, "Characteristics of wollastonite synthesized from rice husk and rice straw", Solid State Science and Technology, 24: 61-69, (2016). [20] S.A. Hallad, B. Siddarath, A. Patil, N.R. Banapurmath, B.B. Kotturshettar, A.M. Hunashyal, "Development of thermal insulation coating for automotive application", Materials Today: Proceedings, 59: 1004-1008, (2022). [21] W.R. Ren, C.H. Wang, C.B. Han, D. Han, J.Y. Zheng, Y.N. Cui, X.M. Song, Q. Jiang, H. Yan, "Cement-based external wall insulation material with thermal performance improvement by partial substitution of calcium silicate", Energy and Buildings, 317: 114415, (2024). [22] D.C. Shong, "Reconsidering Calcium Silicate Pipe and Block Industrial Insulation", Performance, Properties, and Resiliency of Thermal Insulations, 157-174, (2021). [23] E. Ogur, R. Botti, M. Bortolotti, P. Colombo, C. Vakifahmetoglu, "Synthesis and additive manufacturing of calcium silicate hydrate scaffolds", Journal of Materials Research and Technology, 11: 1142-1151, (2021). [24] Kumar, B.J. Walder, A. Kunhi Mohamed, A. Hofstetter, B. Srinivasan, A.J. Rossini, K. Scrivener, L. Emsley, P. Bowen, "The atomic-level structure of cementitious calcium silicate hydrate", The Journal of Physical Chemistry C, 121: 17188-17196, (2017). [25] Z. Yang, D. Kang, D. Zhang, C. Yan, J. Zhang, "Crystal transformation of calcium silicate minerals synthesized by calcium silicate slag and silica fume with increase of C/S molar ratio", Journal of Materials Research and Technology, 15: 4185-4192, (2021). [26] I.G. Richardson, "The calcium silicate hydrates", Cement and concrete research, 38: 137-158, (2008). [27] S. Haastrup, "Impact of Micro Silica on the Properties of Porous Calcium Silicate Products", PhD, Faculty of Engineering and Science, Aalborg Universitet, (2018). [28] H.F. Taylor, "Cement chemistry", 2, Thomas Telford London, (1997). [29] H. Wu, J. Yang, H. Ma, M. Wang, "Preparation of acicular wollastonite using hydrothermal and calcining methods", Integrated Ferroelectrics, 146: 144-153, (2013). [30] F. Liu, L.K. Zeng, J.X. Cao, B. Zhu, A. Yuan, "Hydrothermal synthesis of xonotlite fibers and investigation on their thermal property", Advanced Materials Research, 105: 841-843, (2010). [31] S. Merlino, E. Bonaccorsi, T. Armbruster, "The real structures of clinotobermorite and tobermorite 9 A: OD character, polytypes, and structural relationships", European Journal of Mineralogy, 12: 411-429, (2000). [32] J.E. Burke, "Progress in Ceramic Science: Volume 3", 3, Elsevier, (2016). [33] N. Mostafa, A. Shaltout, H. Omar, S. Abo-El-Enein, "Hydrothermal synthesis and characterization of aluminium and sulfate substituted 1.1 nm tobermorites", Journal of Alloys and Compounds, 467: 332-337, (2009). [34] P. Mandaliev, E. Wieland, R. Dähn, J. Tits, S. Churakov, O. Zaharko, "Mechanisms of Nd (III) uptake by 11 Å tobermorite and xonotlite", Applied geochemistry, 25: 763-777, (2010). [35] S. Shaw, S. Clark, C. Henderson, "Hydrothermal formation of the calcium silicate hydrates, tobermorite (Ca5Si6O16 (OH) 2· 4H2O) and xonotlite (Ca6Si6O17 (OH) 2): an in situ synchrotron study", Chemical Geology, 167: 129-140, (2000). [36] S. Bernstein, "Determination of reaction kinetics and mechanisms of 1.13 nm tobermorite by in-situ neutron diffraction", PhD, Fakultät für Geowissenschaften der Ludwig-Maximilians-Universität (2011). [37] P. Yu, R. Kirkpatrick, "Thermal dehydration of tobermorite and jennite", Concr Sci Eng, 1: 185-191, (1999). [38] K.A. Almasri, H.A.A. Sidek, K.A. Matori, M.H.M. Zaid, "Effect of sintering temperature on physical, structural and optical properties of wollastonite based glass-ceramic derived from waste soda lime silica glasses", Results in Physics, 7: 2242-2247, (2017). [39] R.G. Ribas, T.M.B. Campos, V.M. Schatkoski, B.R.C. de Menezes, T.L. do Amaral Montanheiro, G.P. Thim, "α-wollastonite crystallization at low temperature", Ceramics International, 46: 6575-6580, (2020). [40] S.S. Hossain, P. Roy, "Study of physical and dielectric properties of bio-waste-derived synthetic wollastonite", Journal of Asian Ceramic Societies, 6: 289-298, (2018). [41] S. Boualleg, M. Bencheikh, L. Belagraa, A. Daoudi, M.A. Chikouche, "The combined effect of the initial cure and the type of cement on the natural carbonation, the portlandite content, and nonevaporable water in blended cement", Advances in Materials Science and Engineering, 2017: 5634713, (2017). [42] Alonso, L. Fernandez, "Dehydration and rehydration processes of cement paste exposed to high temperature environments", Journal of materials science, 39: 3015-3024, (2004). [43] K. Baltakys, R. Jauberthie, "Formation and stability of CSH (I) of various degrees of crystallinity in the Ca (OH) 2/CaO-Hi-Sil-H2O system", Mater Sci Pol, 27: 1077-1089, (2009). [44] X. Wang, J. Feng, J.-Y. Hwang, T. Dai, S. Liu, Z. Wu, W. Mo, X. Su, "Hydrothermal synthesis of a novel expanded vermiculite/xonotlite composite for thermal insulation", Construction and Building Materials, 367: 130254, (2023). [45] K. Baltakys, T. Dambrauskas, A. Eisinas, R. Siauciunas, "α-C2SH synthesis in the mixtures with CaO/SiO2= 1.5 and application as a precursor for binder material", Scientia Iranica, 23: 2800-2810, (2016). [46] F. Marti-Montava, A. Opsommer, D. Garcia-Sanoguera, "Influence of Silica Fume Source on Crystallization of Xonotlite in a New Process Making Medium Density Ca-Silicate Based Products", Key Engineering Materials, 788: 3-12, (2018). [47] N.C. Collier, "Transition and decomposition temperatures of cement phases–a collection of thermal analysis data", Ceramics-Silikaty, 60: (2016). [48] H. Song, Y. Jeong, S. Bae, Y. Jun, S. Yoon, J.E. Oh, "A study of thermal decomposition of phases in cementitious systems using HT-XRD and TG", Construction and Building Materials, 169: 648-661, (2018). [49] S. Mingione, B. Lothenbach, F. Winnefeld, A. Opsommer, "Study of the solubility of xonotlite", ce/papers, 6: 238-245, (2023). [50] Y. Yan, H. Wang, "Thermal Behavior and Determination of the Heated Structure of 11Å Anomalous Tobermorite by in situ X-ray Diffraction", Acta Geologica Sinica - English Edition, 95: 810-829, (2021). [51] R. Siauciunas, G. Smalakys, A. Eisinas, E. Prichockiene, "Synthesis of high crystallinity 1.13 nm tobermorite and xonotlite from natural rocks, their properties and application for heat-resistant products", Materials, 15: 3474, (2022). [52] R. Siauciunas, L. Steponaityte, M. Dzvinka, A. Kareiva, Influence of Al2O3 Additive on the Synthesis Kinetics of 1.13 nm Tobermorite, and Its Crystallinity and Morphology, Materials, (2025). [53] S. Shaw, C. Henderson, B. Komanschek, "Dehydration/recrystallization mechanisms, energetics, and kinetics of hydrated calcium silicate minerals: an in situ TGA/DSC and synchrotron radiation SAXS/WAXS study", Chemical Geology, 167: 141-159, (2000). [54] O. Shichalin, A. Tarabanova, E. Papynov, A. Fedorets, I.Y. Buravlev, O. Kapustina, Z. Kornakova, V. Gribova, S. Gribanova, "Hybrid microwave solid-phase synthesis of wollastonite based on natural renewable raw materials", Russian Journal of Inorganic Chemistry, 67: 1400-1407, (2022). [55] M.K. Kar, C. Van Der Eijk, J. Safarian, Hydrogen reduction of high temperature sintered and self-hardened pellets of bauxite residue produced via the addition of limestone and quicklime, Proceedings of the 40th International ICSOBA Conference, Athens, Greece, , pp. 10-14. (2022). [56] J.H. Perry, Chemical engineers' handbook, ACS Publications, (1950). [57] R.R. John, CRC handbook of Chemistry and Physics, CRC Press Boca Raton, (2019). [58] Hartmann, D. Schulenberg, J.-C. Buhl, "Synthesis and structural characterization of CSH-phases in the range of C/S= 0.41-1.66 at temperatures of the tobermorite xonotlite crossover", Journal of Materials Science and Chemical Engineering, 3: 39-55, (2015). [59] M. Khachani, A. El Hamidi, M. Halim, S. Arsalane, "Non-isothermal kinetic and thermodynamic studies of the dehydroxylation process of synthetic calcium hydroxide Ca (OH) 2", Journal of Materials and Environmental Science, 5: 615-624, (2014). [60] G. Smalakys, R. Siauciunas, "Peculiarities of xonotlite synthesis from the raw materials with different SiO 2 activities", Journal of Thermal Analysis and Calorimetry, 142: 1671-1679, (2020). [61] P. Yu, R.J. Kirkpatrick, B. Poe, P.F. McMillan, X. Cong, "Structure of calcium silicate hydrate (C‐S‐H): Near‐, Mid‐, and Far‐infrared spectroscopy", Journal of the American Ceramic Society, 82: 742-748, (1999). [62] B. Lothenbach, A. Nonat, "Calcium silicate hydrates: Solid and liquid phase composition", Cement and concrete research, 78: 57-70, (2015). [63] Hamilton, P. Bots, H. Zhou, B. Liu, C. Hall, "Clean-up of divalent cobalt ions by massive sequestration in a low-cost calcium silicate hydrate material", Scientific Reports, 14: 7052, (2024). [64] N. Meller, C. Hall, J.S. Phipps, "A new phase diagram for the CaOAl2O3SiO2H2O hydroceramic system at 200° C", Materials Research Bulletin, 40: 715-723, (2005). [65] U. Anjaneyulu, S. Sasikumar, "Bioactive nanocrystalline wollastonite synthesized by sol–gel combustion method by using eggshell waste as calcium source", Bulletin of Materials Science, 37: 207-212, (2014). [66] R. Dordane, M.M. Doroodmand, "Novel method for scalable synthesis of wollastonite nanoparticle as nano-filler in composites for promotion of anti-corrosive property", Scientific Reports, 11: 2579, (2021). [67] N.-H. Hoang, T.T. Trinh, "A first-principles insight into thermodynamic and mechanical properties of Xonotlite and Wollastonite phases of high temperature geothermal well cement", Results in Materials, 20: 100454, (2023). [68] Kuzielová, M. Slaný, M. Žemlička, J. Másilko, M.T. Palou, Phase Composition of Silica Fume—Portland Cement Systems Formed under Hydrothermal Curing Evaluated by FTIR, XRD, and TGA, Materials, 14: 2786, (2021). [69] Morandeau, M. Thiéry, P. Dangla, "Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties", Cement and concrete research, 56: 153-170, (2014).