Symposium CN
Science and Technology for Silicate Ceramics
ABSTRACTS
Session CN-1 Green and sustainable silicate ceramics
CN-1:IL01 Lowering the Firing Temperature of Ceramic Bricks through the Incorporation of Biomass Fly Ash: Physical, Mechanical, and Microstructural Insights
P. MUÑOZ, M. VIDAC-VASIC, C. GONZÁLEZ-MENORCA, O. GENCEL, Universidad Internacional de La Rioja, Logroño, Spain
The brick industry commonly requires firing temperatures above 900 °C, leading to high energy demand and carbon emissions. This study examines the incorporation of biomass fly ash (BFA) as a fluxing additive to reduce the firing temperature of ceramic bricks while maintaining suitable mechanical and physical performance. Clay was partially replaced with 0–30 wt% BFA, and samples were fired at 500, 600, and 900 °C. XRD, SEM/EDS, and TGA analyses confirmed that BFA promotes earlier vitrification through fluxing oxides such as K₂O, CaO, Fe₂O₃, and MgO. Bricks with up to 20 % BFA achieved adequate sintering and compressive strength increases of up to 34 % at only 600 °C—about 300 °C lower than conventional firing. Additionally, a life cycle impact assessment (LCIA) was performed to evaluate the environmental implications of the reduced firing temperature. The results demonstrate the potential of BFA to lower energy consumption and carbon footprint in ceramic brick production.
CN-1:IL02 The Influence of Water-Soluble Fluxing Agents and their Application Method on the Sintering Temperature and Properties of Ceramic Materials
E. KŁOSEK-WAWRZYN, A. FLORKOWSKA, A. KOCOŁ, AGH University of Krakow, Krakow, Poland
This study examines the potential of water-soluble fluxes to lower the sintering temperature of structural ceramics while maintaining the desired mechanical and thermal properties. Conventional ceramic production requires high firing temperatures exceeding 900°C, leading to significant energy consumption and CO₂ emissions. The project is investigating an alternative approach involving the introduction of water-soluble sodium and potassium compounds (such as borates, phosphates, acetates, benzoates, and citrates) with melting points lower than the decomposition temperature of carbonates present in clay raw materials. Various application methods were tested: (i) spraying flux solutions onto pore-forming additives prior to granulation, (ii) applying the solutions to the granulate surface prior to shaping, and (iii) combining both techniques. The experimental program included high-temperature microscopy and dilatometry to determine sintering properties, DTA/TG analysis of CO₂ release, and microstructural and mechanical characterization of the fired bodies. Results indicate that water-soluble fluxes can effectively support liquid-phase sintering and surface vitrification, improving material strength without significantly increasing density.
CN-1:IL03 Sustainability in the Ceramic Tile Industry: Necessity, Constraints and Opportunities
S. CONTE1, C. MOLINARI1, R. ARLETTI2, A. GUALTIERI F. 2, C. ZANELLI1, 1Istituto di Scienza, Tecnologia e Sostenibilità per lo Sviluppo dei Materiali Ceramici (CNR- ISSMC), Faenza (RA), Italy; 2Dipartimento di Scienze Chimiche e Geologiche – Università degli Studi di Modena e Reggio Emilia, Italy
Following a post-pandemic recovery in the ceramic industry—especially in porcelain stoneware—demand for raw materials has increased. However, challenges such as the shortage of Ukrainian clays (due to the 2022 war) and the inclusion of feldspar in the EU list of critical raw materials (2023) have pushed manufacturers to explore alternative solutions. The use of waste-derived materials remains limited, mainly due to limited knowledge of their effects on processing and product performance. This work presents two case studies on the use of secondary raw materials in porcelain stoneware production. Promising results were achieved at laboratory scale (TRL4), enabling scale-up to pilot plant trials in collaboration with industry (TRL6).
This research is financed by “Fibre Vetrose per ceramici green” financed by Ministero dell’Ambiente e della Sicurezza Energetica2022 CUP E93C23002050006. Alessandro F. Gualtieri and Rossella Arletti thanks Project 101113855 – LIFE22-ENV-IT-LIFE ReWo cofunded by the European Union. Sonia Conte thanks the Project ECOSISTER (ECS_00000033) under the National Recovery and Resil ience Plan (NRRP), Mission 04 Component 2 Investment 1.5—Next Generation EU.
CN-1:IL04 New Alkaline-activated Materials from Waste for a Circular Economy
L. PÉREZ-VILLAREJO, S. BUENO-RODRÍGUEZA, D. ELICHE-QUESADA, Department of Chemical, Environmental, and Materials Engineering, Higher Polytechnic School of Jaén, University of Jaén, Campus Jaén, Spain; and Center for Advanced Studies in Earth Sciences, Energy and Environment (CEACTEMA), University of Jaén, Jaén, Spain
The present study encompasses the synthesis of alkali-activated materials using unconventional raw materials, such as waste products, their additive manufacturing, and the induction of controlled porosity for environmental applications. The partial replacement of metakaolin with calcined clays, steel slags, construction and demolition wastes (CDWs), biomass ashes, and spent filter earths contributes to the circular economy by reducing both economic costs and environmental impact. Among the challenges that must be addressed when using industrial waste as raw materials are the lack of homogeneity between waste batches, which limits scalability; the need to enhance the reactivity of the wastes due to the presence of poorly reactive crystalline phases; the optimization of the activator-to-precursor ratio; and the search for new alkaline activators capable of reducing the carbon footprint by replacing conventional commercial ones. Potential applications derived from optimal control of the porosity in these materials range from their use as membranes in wastewater treatment to their employment as catalytic supports.
CN-1:IL05 The “Yellow Cobblestones” of Sofia - an Intriguing Marl Ceramic Clinker with Outstanding Characteristics
A. KARAMANOV1, E. KARAMANOVA1, V. KOSTOV-KYTIN2, 1Institute of Physical Chemistry “Rostislaw Kaischew” Bulgarian Academy of Sciences, Sofia, Bulgaria; 2Institute of Mineralogy and Crystallography "Acad. Ivan Kostov" Bulgarian Academy of Sciences, Bulgaria
A brief history of longstanding “yellow cobblestones” of Sofia is presented. This pavement was produced in Budapest from local marl with a specific composition. By the end of the 19th century, the area covered with this pavement in Hungary and abroad was approximately 1 km2. Today, the largest preserved area is the historic center of Sofia. This material is characterized by virtually zero water absorption and high crystallinity due to the formation of fine pyroxene and plagioclase phases. As a result, its mechanical properties significantly exceed those of modern ceramic clinkers. Indeed, it has withstood more than a century of heavy traffic and climate change. The peculiarities of sintering, structure, and phase formation of this ancient ceramic are discussed. The data are compared with similar results for a typical modern clinker product. It is shown that the combination of excellent sintering degree and high crystallinity is the result of relatively low viscosity during the sintering process and phase formation, which occurs during cooling. It is also shown that the sintering interval is narrow, which creates some technological difficulties. Finally, the results of the synthesis of new compositions close to the original are presented. Bulgarian marls were used in these experiments, but they contain a lower percentage of MgO. This difference was successfully compensated by adding asbestos waste or other Mg-rich natural raw materials to the batch.
CN-1:L06 Recycled Geomaterials Mimicking Natural Raw Materials: A Sustainable Opportunity for the Ceramic Sector
S.F. GRAZIANO1, P. CAPPELLETTI2, M. DONDI3, C. MOLINARI3, C. RISPOLI2, C. ZANELLI3, 1Dipartimento di Farmacia - Università degli Studi di Napoli Federico II, Napoli, Italy; 2Dipartimento di Scienze della Terra dell'Ambiente e delle Risorse - Università degli Studi di Napoli Federico II, Napoli, Italy; 3CNR-ISSMC Istituto di Scienza, Tecnologia e Sostenibilità per lo sviluppo dei Materiali Ceramici – Faenza, Italy
Industrial waste generated during the processing of natural stones poses both logistical and environmental challenges. Although these by-products may exhibit minor contamination due to production processes—such as wear from (diamond) cutting tools or abrasive powders used for polishing—they still retain to large extent the mineralogical and chemical composition of the original material. This characteristic makes them especially appealing as potential secondary resources for various industrial applications. On this basis, residues and by-products obtained from cutting and processing building stones -particularly those from volcanic tuff deposits containing primary minerals (such as feldspars) and secondary minerals (such as zeolites)—can be classified as secondary raw materials. When properly processed and valorized, these materials can be used in various production sectors, contributing not only to reducing disposal costs but also to conserving primary natural resources. Technological testing on such waste has yielded promising results: recovered materials demonstrate strong potential for reuse, for instance, in the production of lightweight aggregates or as partial substitutes for feldspathic fluxes in traditional ceramic mixtures, promoting more sustainable products.
CN-1:L07 Studies on Sustainable Manufacturing of Ceramic Table-wares through Wet Processed Soda Feldspar
C. AGARWAL1, L.K. SHARMA2, 1Mactus Mineral LLC, Dubai, UAE; 2Mahamana Ceramic Development Organization, Khurja, India
Studies were carried out by using the wet processed soda feldspar in manufacturing compositions of Ceramic Stoneware, Hotel wares and data was compared with the formulations based on dry processed soda feldspar. Fired Rejections and thermal energy consumption were found to get reduced by 10-12% and 4-5% respectively. Quality of the wares was improved by more than 5%. All these studies were conducted by controlling the L > 87 in Glaze, L > 80 in base body, Fe2O3 in the range of 500-800 ppm, b < 4 for glaze and b < 5 for base body for wet processed feldspar w.r.t L<80, Fe2O3 in the range of 1200-3000 ppm and b > 6 of dry processed soda feldspar respectively, Particle size for the both was maintained as (-) 200 mesh. Cost benefits have been analysed though reduction in zirconium silicate opacifier by >5% and vitrification temperature from 1200 degree centigrade to 1190 degree centigrade. XRD and SEM studies confirmed the reduction in impurities like mica and Fe2O3 with clear mullite peaks and needle shaped crystals contributing to better physical properties like water absorption, apparent porosity and fired strength (MOR).
CN-1:IL08 Elaboration of Low-energy Consuming Materials
G.L. LECOMTE-NANA, IRCER (UMR CNRS 7315), ENSIL-ENSCI, University of Limoges, Limoges, France
Since the last decade, the sustainable development and ecological transition have been at the center of many concerns worldwide. Namely, environmental issues related to water, natural resources and waste must be considered; emissions and energy consumption must be reduced. In this context, the ceramic industry needs to follow environmental developments towards a “competitive low-carbon economy by 2050”. The processing of most silicate ceramics involves the use of natural occurring raw materials and requires heat treatments in the range 900 to 1600°C depending on the compositions and the final applications. Reducing the carbon footprint and energy demand for manufacturing silicate ceramics requires both a deep consideration of reformulation of the starting mixtures and the improvement of heating systems and regimes. Our contribution will emphasize on the « reformulation » of the starting mixtures, including the recycling of ceramics, valorization of various type of wastes (organic and inorganic) and the development of alkali activated materials. A critical analysis of sustainable use of resources, circularity and composition-structure-properties will be presented. Besides, the heating regime and thermodynamic evolution of some silicate systems will be explored regarding the energy.
CN-1:L09 Effects of Raw Material Changes on the Composition and Mechanical Behaviour of Porcelain Stoneware Tiles
M. SISTI, A.F. GUALTIERI, R. ARLETTI, University of Modena and Reggio Emilia, Modena, Italy; W. PABST, E. GREGOROVÁ, P. ŠIMONOVÁ, University of Chemistry and Technology Prague, Prague, Czech Republic
The most important clays for the production of porcelain stoneware bodies have always been considered the Ukrainian clays coming from the Donbass region. The Russian – Ukrainian conflict has forced the ceramic industries to search for new clays coming from alternative regions around the world and to change the bodies formulations. Following these changes, several problems of breakages during the cutting of large slabs were encountered. This work aimed at the understanding of what has changed in porcelain stoneware formulations after the replacement of Ukrainian clays and how these changes affected the technological properties of the tiles. The idea was to combine different analytical techniques such as X-ray fluorescence (XRF) and X-ray Powder Diffraction (XRPD) to investigate the chemical and mineralogical composition of bodies batches and fired slabs produced before and after the replacement of Ukrainian clays. Furthermore, we used Impulse Excitation Technique (IET) to determine the Young’s modulus and damping of the samples at room temperature and their dependence on temperature. Finally, we determined the porosity of the fired slabs and subsequently we investigated its relationship with the chemical and mineralogical composition and the Young’s modulus.
CN-1:L10 Study on the Incorporation of Fly Ash as Secondary Material in the Formulation of Conventional Refractory Castable to Increase the Percentage of Recycled Waste and Achieve Sustainable Development
J.F. LÓPEZ PERALES, L. DÍAZ-TATO, S.U. COSTILLA-AGUILAR, F. BANDA-MUÑOZ, E.A. RODRÍGUEZ, Universidad Autónoma de Nuevo León (UANL), Facultad de Ingeniería Mecánica y Eléctrica (FIME), Programa Doctoral en Ingeniería de Materiales, San Nicolás de los Garza, Nuevo León, México
The percentage of fly ash currently recycled remains significantly low, considering the amount of waste generated annually; therefore, more applications are needed to manage and utilize this SiO2- and Al2O3-rich waste. In this research work, four conventional refractory concrete formulations were designed from bauxite, flint clay, kyanite 48, Secar 80, and microsilica, in which fly ash replaced the fine flint clay particles at 0, 5, 10, and 15 wt.%. The specimens prepared were heat treated at 120, 850, 1050, and 1400 ºC, and the density, porosity, water absorption, compressive strength, and flexural strength were analyzed and compared with the mineralogical evolution (XRD) and the microstructure developed at the maximum temperature (SEM-EDAX). The results confirm that the incorporation of up to 10 wt.% of fly ash in the refractory composition is feasible, since the mechanical resistance is higher from intermediate temperatures (1050 ºC) and at the maximum sintering temperature (1400 ºC) than that of the reference concrete thanks to the in-situ secondary mullite development in the refractory matrix through a SiO2-rich liquid phase with impurities from the waste.
Session CN-2 Glasses, glazes and pigments
CN-2:IL11 Synthesis and Characterization of Lithium Aluminium Silicate-containing Materials
O.R.K. MONTEDO1, J.M. INOCENTE1, R. MORENO2, S. ARCARO1, 1Laboratório de Cerâmica Técnica (CerTec), Programa de Pós-graduação em Ciência e Engenharia de Materiais (PPGGEM), Universidade do Extremo Sul Catarinense (UNESC), Criciúma (SC), Brazil; 2Institute of Ceramics & Glass, CSIC, Madrid, Spain
Glass ceramics based on lithium aluminosilicates are interesting because they have low coefficients of thermal expansion (CTEs) and are adjustable to different processes by adjusting their chemical composition. However, their typical production is complex, requiring high process temperatures and long grinding times to obtain micrometric particles. This study presents the synthesis of low–CTE lithium aluminium silicate nanoparticles obtained through a colloidal approach from the heterocoagulation of a lithium source (lithium acetate obtained by the reaction of carbonate with acetic acid), silica, and alumina from different sizes. The concentrated suspensions were dried, and the powders were thermally treated at 750–900 °C to form the crystalline phases projected by the solid–state reaction. The samples were characterized by thermal and structural analysis. The use of alumina nanoparticles in the synthesis of powders yielded mostly the crystalline phases β–spodumene and β–eucryptite, which were thermally treated at 850 °C and showed a low CTE (1.25 × 10−6 °C−1). Powders were successfully synthesized, which with some adjustments in the synthesis conditions may yield higher levels of β–eucryptite and therefore much lower CTE powders.
CN-2:IL12 Development of Sustainable Glazes for Stoneware Products
M.P. SEABRA, M.N. CAPELA, I. VILARINHO, I. VIEIRA, CICECO – Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, Aveiro, Portugal; J. CARNEIRO, Grestel - Produtos Cerâmicos S.A, Vagos, Portugal
Glazes play a fundamental role in ceramic tableware, serving both functional and aesthetic purposes. Functionally, they ensure impermeability, facilitate cleaning, protect the ceramic surface, and improve resistance to wear and to chemical agents such as detergents. Aesthetically, glazes provide colour, gloss, and decorative effects that enhance the visual appeal and distinctiveness of ceramic products. Nevertheless, glazes are considered one of the major contributors to water consumption, hazardous waste generation, and environmental impact within the ceramic industry. Their relatively high cost also has a significant influence on the final price of ceramic products. Therefore, improving glaze formulations is a key strategy to reduce both the environmental footprint and production costs. In this study, industrial wastes such as deburring waste from an iron foundry and sludge from the effluent treatment of a steel wire drawing company were used as coloring agents in the formulation of innovative glazes for single-firing stoneware products, and as raw materials for granulated glazes. Furthermore, glaze formulations that maximize the use of local raw materials while minimizing the proportion of pre-processed raw materials (e.g., frits) were developed and characterized.
CN-2:L13 A Comprehensive View of Mullite Formation in Porcelain
W. CARTY, HYOJIN LEE, New York State College of Ceramics at Alfred University, Alfred, NY, USA
For over 25 years we have been studying the formation of mullite in porcelains, not for the purpose of determining the mullite level, but to use mullite and undissolved quartz, to determine the chemistry of the glass phase. Through the use of an internal standard method, based on comparing three peak areas for the desired mineral phase (mullite, quartz, cristobalite, corundum) to the peak areas of CaF2 (added as an internal standard), we discovered that the amount of mullite formed in porcelain bodies was dictated by the amount of alumina that could dissolve into the glass phase. We postulated that this level of alumina, 1.2 moles of alumina per mole of flux, identified the glass formation boundary in the system. Interestingly, in recent years, there has been a proliferation of literature in which Rietveld analysis has been used to measure the mullite level in porcelains, but surprisingly, these data do not align with the hypothesis of the glass formation boundary, generating a very broad range of mullite levels and, correspondingly, glass chemistries. We have identified the root cause of this discrepancy and provide an argument explaining why the Reitveld-obtained mullite levels are likely incorrect.
CN-2:L14 Eco-friendly Precipitation Synthesis of Egyptian Blue (CaCuSi4O10) pigment
Z.A. HOVHANNISYAN, A.R. ISAHAKYAN, A.M. TERZYAN, I.A. PETROSYAN, H.A. BEGLARYAN, Institute of General and Inorganic Chemistry of the NAS RA, Yerevan, Armenia
Due to its vivid blue color and high stability, Egyptian blue, also known as cuprorivaite (CaCuSi4O10), has been requested as a pigment for centuries. Recently, it became more popular due to its other functional characteristics, such as its outstanding NIR photoluminescence. In this work, an energy-efficient and time-saving precipitation method of synthesis for Egyptian blue was experimented to replace its traditional solid-state and hydrothermal routes requiring high temperature with long processing time. The suggested method produces precipitate from a boiling solution of CaCl2, CuCl2, SiO2 and NaOH, which are safe and inexpensive materials. Then the precipitate is calcined with an optimized temperature and time ratio. These stages of synthesis make reaction conditions relatively softer and produce homogeneous components with a final yield of 90-99%. Egyptian blue synthesised by the precipitation method can be used not only as a pigment, but it is also being experimented in other applications, for example, as a nanosheet, due to its suitable particle sizes and well-expressed optical characteristics.
The research was supported by the Higher Education and Science Committee of MESCS RA (Research project № 24LCG-1D017).
CN-2:IL15 Non-invasive Characterization of Experimental Ceramics and Tiles Unearthed at the İznik Tile Kilns Excavation
G. ŞİMŞEK FRANCİ, Department of Metallurgical and Materials Engineering, Istanbul Gedik University, Istanbul, Türkiye
The underglaze color palettes employed by master potters have been identified for the first time among the finds from the İznik Tile Kilns Excavation. These experimental fragments, sometimes referred to as çeşni by Turkish art historians, comprise various glaze types and pigment colors, including red, turquoise, blue, green, and black outlining. The assemblage includes both double-sided glazed and decorated ceramic pieces, as well as single-sided glazed tiles with plain reverse surfaces. The presence of regularly shaped perforations in certain examples suggests that these specimens were suspended within the kiln during firing. The ceramic bodies of the test pieces are of the stonepaste type. The absence of samples with red clay bodies suggests that these experimental productions were likely manufactured over a short and specific period.
CN-2:IL16 ZnO, SrO, BaO, their Role and Influence on the Structure and Properties of Ceramic Glazes
K. PASIUT, J. PARTYKA, D. KOZIEŃ, AGH University of Krakow, Faculty of Materials Science and Ceramics, Department of Ceramics and Refractory Materials, Krakow, Poland
Zinc oxide, barium oxide, and strontium oxide, according to the Seger formula, belong to the first group, meaning they act as modifiers of the glaze structure. They are used in ceramic glazes not only as fluxes but also as components participating in the crystallization process. In this work, the role of these three oxides was investigated in the SiO₂–Al₂O₃–CaO–MgO–Na₂O/K₂O system. All samples were prepared using both base and natural raw materials commonly used in the ceramic industry. Zinc oxide was introduced in oxide form, whereas strontium and barium oxides were added as carbonates. Each glaze was wet-milled, dried in a laboratory dryer, and fired at approximately 1220 °C in a laboratory furnace. Each group of glazes containing the added oxides was analyzed using methods such as hot-stage microscopy (HSM), mechanical dilatometry (DIL), thermal analysis (DSC–TG), structural analysis (MIR, Raman), and microstructural observations (SEM–EDS). The obtained results indicate the role and influence of the added oxides on the glaze structure after firing.
This research was funded by the National Science Center, Poland (grant MINIATURA 8, no. 2024/08/X/ST5/01528).
CN-2:IL17 Development of Willemite Crystals on Stoneware Glaze
L.K. SHARMA, Mahamana Ceramic Development Organization, Khurja, India
Studies were carried out for the development of Willemite crystals for the table-wares of stoneware category glazes. Cobalt oxide was used for the development of blue color crystals at 1250 °C in regular electric kiln firing for 10,20,30 and 40 min soaking. Controlled properties were density of the glaze slip, thickness and dipping time. After firing the samples were taken for hardness, macroscopic, thermal expansion, XRD, SEM and EDAX studies as a part of confirmation and development. Largest spherulites crystals gave the diffraction peaks belonging to willemite {Co Zn (SiO4)} and gahnite {Zn Co (Al2O4)}. As gahnite crystals were not seen in any of the samples it was concluded that gahnite crystals formation was accelerated by the addition of 3% CoO. The Co doped willemite {ZnCo (SiO4)} and gahnite {ZnCo (Al2O4)} crystals were formed by the incorporation of Co (II) into the Zn (II) crystal site in willemite and gahnite lattice without any change of willemite and gahnite lattice. The rod shaped willemite crystals in smallest spherulites and rod shape willemite & star shaped gahnite crystals in largest spherulites were observed in SEM photographs supported by XRD. EDAX analysis supported the results.
CN-2:L18 A Borax- and Fluoride-Free Precipitation Approach of Victoria Green Pigment
A.A. KIRAKOSYAN, A.R. ISAHAKYAN, A.M. TERZYAN, V.G. STEPANYAN, H.A. BEGLARYAN, Institute of General and Inorganic Chemistry of the NAS RA, Yerevan, Armenia
Victoria Green (Ca₃Cr₂Si₃O₁₂) is a pale green pigment widely used in art and ceramics. In addition to the traditional solid-state reaction, sol–gel and hydrothermal methods have also been proposed for its synthesis. However, these approaches often rely on organic, nitrate-, or carbonate-based reagents and typically require borax- or fluoride-containing mineralizers. Such components can release environmentally harmful gases during processing, thereby complicating and increasing the cost of production. In this work, a cost-effective and environmentally friendly precipitation method is proposed that avoids these drawbacks. A boiling aqueous solution containing NaOH, SiO₂, CrCl₃, and CaCl₂ was stirred and subsequently dried in a water bath, leading to the formation of a precursor precipitate. Upon crystallization at 900 °C, this material yielded syn. Uvarovite, which represents a mixture containing Victoria Green and related phases. Subsequent purification of the product resulted in high-purity Victoria Green pigment, exhibiting excellent color quality and thermal stability when tested in ceramic glaze applications.
The research was supported by the Higher Education and Science Committee of MESCS RA (Research project № 24LCG-1D017).
CN-2:IL19 Ultrafast Development of Blue Pigment for In Situ Laserdigital Coloration in the Ceramic Industry
J.B. CARDA, A. LAHLAHI-ATTALHAOUI, J. GONZÁLEZ CUADRA, S. PORCAR GARCÍA, S. LUIS TOCA, Universitat Jaume I, Castellon, Spain
This study presents a fast and simple method for digital ceramic coloration usinginkjet printing, eliminating the need for traditional precalcined pigments. Thisinnovative approach represents a breakthrough in ceramic decoration technol-ogy, and introduces a previously unexplored methodology. In this work, CoAl2O4spinel, a pigment commonly used in industrial contexts, is synthesized throughlaser zone melting (LZM) by applying pulsed laser radiation at 1064 nm. Astandardized methodology to optimize pigment quality is developed, based onlaser parameters such as pulse width, frequency, speed, power, and line spac-ing. Scanning electron microscopy (SEM) is used to determine the optimal laserconditions for obtaining a continuous, defect-free coating, showing that theembedded particles on the surface exhibit a nearly spherical morphology withdiameters below 100 nm. The sample with the highest surface quality is fur-ther analyzed structurally and optically. X-ray diffraction (XRD) confirms thepresence of a pure spinel phase without secondary phases, along with a vitre-ous phase due to pigment embedding. Fourier-transform infrared spectroscopy(FTIR) and Raman spectroscopy reveal the characteristic vibrational bands of anormal spinel structure. The intense blue color is confirmed by strong absorption at 560 nm in ultraviolet–visible (UV–Vis) spectroscopy, as well as b* and Δb* values of 29 and 1.58, respectively, compared to the traditional pigment. This synthesis approach significantly enhances digital ceramic coloration compared to other methods evaluated in this study, offering a scalable, flexible, and more efficient alternative suitable for industrial-scale production.
Session CN-3 Innovative processing
CN-3:L21 Comparison of Porcelain Stoneware Tiles Fired in Traditional, Hydrogen and Electric Kilns
G. OREFICE1, B. FERRARI1, M.C. BIGNOZZI2, E. FRANZONI1,2, 1Centro Ceramico, Sassuolo (MO), Italy; 2Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, University of Bologna, Bologna, Italy
As the production of ceramic tiles involves high-energy processes that significantly affect both operating costs and the overall environmental impact, a growing attention is addressed to sustainability improvement. In this context, the Spoke 3 of the ECOSISTER project, funded by the European Union Next-GenerationEU (PNRR), focuses on green manufacturing for a sustainable economy. This paper investigates how energy-efficient firing technologies influence the properties of final tiles. Tiles fired in electric and hydrogen kilns were analyzed and compared with those produced in traditional kilns. Characterization tests were performed both in the body and the surface of the tiles, according to international standards, to assess whether tiles fired in hydrogen or electric kilns achieve performance comparable to those obtained with the conventional process. The results show that the properties of tiles fired in alternative kilns are comparable, or even superior, to those of tiles produced using traditional kilns. In particular, the surface analyses show a slightly better performance of samples fired in electric or hydrogen kilns. Moreover, tiles fired with alternative technologies exhibit a significantly improved behavior in terms of water absorption.
CN-3:L22 Direct Ink Writing of Porous Clay-Based Ceramics
I.Q. MAURY NJOYA1, E. JUSTE2, F. CASARRUBOIS3, G.L. LECOMTE-NANA1, S. ABDELOUHAB2, C. DELMOTTE2, M. GONON3, Y. EL HAFIANE1, C. PEYRATOUT1, 1Institute of Research for Ceramics IRCER UMR CNRS 7315, Limoges, France; 2Belgian Ceramic Research Centre BCRC, Mons, Belgium; 3Materials Institute, University of Mons, Mons, Belgium
AM has emerged as a promising process route for manufacturing complex-shaped ceramic parts compared to conventional techniques. The present work aims to develop porous clay-based ceramic using robocasting. Three raw clays from Cameroon were selected (denoted H, K and M). Different pastes were prepared together with distilled water, sodium hexametaphosphate and stearic acid. The initial stage of the process involves optimizing the rheological behavior of the clay pastes. To this end, a solid load range of 44 – 47 wt.% (relative to the clay content) was selected based on the clay. From these optimized pastes, samples KAM, HAM, and MAM were shaped. Then, air dried, oven dried and sintered at 1100 °C, 5 °C/min, 1h. The essential results showed that, the density values of the three clays were in the range 2.55 to 2.65 g/cm3 which aligns with expected values. The particle size values (d90) were less than 35 µm. The open porosity values of the porous ceramics were significantly higher in KAM and HAM (over 40%) compared to MAM (20%). The lower porosity observed in MAM was attributed to the rearrangement of particles and the closure of the finest pores in the material under the effect of sintering. SEM analysis revealed a compact, porous and oriented microstructure.
CN-3:IL23 Additive Manufacturing of Glass Materials using Powder Bed-based Processes
E. JUSTE, C. KERMEL, F. PETIT, Belgian Ceramic Research Centre, Mons, Belgium
Glass, combining unique properties such as transparency, chemical and thermal resistance, and high electrical resistivity, remains a key material for numerous technological sectors such as electronics, chemistry, medical technology, automotive, aerospace, architecture ... Compared to other materials, additive manufacturing of glass remains less mature. This work deals with the additive manufacturing of a silico-aluminous glass powder using two powder bed-based routes: Powder Bed Fusion (PBF) and Binder Jetting (BJ). As for PBF, a process map was established, defining the operational window for reproducible consolidation of the silico-aluminous glass powder. As for BJ, optimized parameters enabled the fabrication of complex geometries. Specimens reached relative densities up to 96.6 ± 0.5% and a three-point bending strength of 115 ± 9MPa. These results confirm the applicability of powder bed-based AM for silico-aluminous glass and open new perspectives for the production of dense and complex structural components. Improving optical transparency remains a major goal for forthcoming developments.
CN-3:IL24 Powder Granulation in Ceramic Tile Production: Progress and Challenges
C. ZANELLI1, S. CONTE1, C. MOLINARI1, M. DONDI1, F. MARANI2, 1CNR-ISSMC Istituto di Scienza, Tecnologia e Sostenibilità per lo sviluppo dei Materiali Ceramici, Faenza, Italy; 2LB Officine Meccaniche S.p.A., Fiorano Modenese (MO), Italy
In the production of ceramic tiles, the characteristics of the starting powders play a critical role in determining the overall quality and performance of the final product. Despite their importance, powder properties are often overlooked or underestimated in industrial practice. Key parameters such as particle size distribution, moisture content, flowability, and packing density exert a direct influence not only on the compaction behavior during forming, but also on the kinetics of sintering and the evolution of texture and microstructure during firing. This paper aims to overview the technologies used for powder granulation in the ceramic tile industry, as an alternative to spray drying. Attention is focused on the characteristics and technological behaviour of granulates obtained with different techniques, based on original and literature data. The goal is to highlight the actual industrial development in the last two decades and the progress of scientific knowledge that has accompanied it. In addition, it is intended to reveal the bottlenecks that need improved technological know-how and deeper scientific insights to keep up with the demand of a sector in constant product and process innovation.
CN-3:IL25 Ceramic Additive Manufacturing in 2025: Market Reality, Technical Maturity, and the Road to Scaled Adoption
M.P. GOMEZ-TENA, ITC-AICE, Castellon, Spain
Over the past decade, ceramic additive manufacturing has progressed from a prototyping method to a mature technology serving specialized sectors such as healthcare, microdevices, casting cores, and radiofrequency components. The most established approaches—photopolymerization of ceramic suspensions, binder deposition followed by sintering, extrusion of pastes, and nanoparticle jetting—enable the production of advanced ceramic components with reliable mechanical and functional properties. Laser-based powder fusion remains constrained by thermal cracking and residual stress, although materials, process control, and post-sintering workflows have improved significantly. The field has grown steadily but below early expectations, concentrating on high-value, low-to-medium-volume applications where geometric freedom, precision, and miniaturization outweigh throughput limitations. Persistent challenges include achieving predictable sintering with minimal distortion, improving automation and productivity, broadening the range of functional and recyclable materials, and correlating microstructure with performance. This presentation provides a critical overview of the sector, highlighting its current strengths, limitations, and future opportunities for industrial expansion.