Michele Dondi

Michele Dondi
Italian National Research Council | CNR · Institute of Science and Technology for Ceramics ISTEC

About

298
Publications
150,345
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Introduction
My scientific activity is focused on product and process innovation in traditional ceramic materials: wall and floor tiles, ceramic pigments and glazes, bricks and roof tiles, refractory and technical ceramics. Exploitation and characterization of ceramic raw materials, including recycling of industrial wastes and byproducts. Modelling the dependance of semi-finished and finished products performances on process conditions and raw materials composition.
Additional affiliations
December 1988 - October 2015
Italian National Research Council
Position
  • Head researcher

Publications

Publications (298)
Article
The purpose of this study is to evaluate different lightweight concretes for the first time formulated with lightweight expanded aggregates produced only with industrial waste. The motive is that a lack of knowledge still exists in the literature about how to integrate these waste-based aggregates in lightweight concrete To achieve the desired bloa...
Article
Full-text available
In recent years, the management of construction and demolition residues (CDRs) has become a major challenge for the construction industry due to the increasing volume of waste produced and its associated environmental impact. The aim of this article is to assess the effect of fine-grained fractions (<0.125 mm–0.6–0.125 mm) of construction and demol...
Article
The growing demand for fluxes, dictated by the shift towards porcelain stoneware, is urging the ceramic tile industry to find a viable alternative to feldspathic materials. Sericite, a microcrystalline form of muscovite, is present in many ceramic raw materials. It melts during firing and can be a suitable substitute for potassic feldspar. The aim...
Article
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In the last years, the ceramic sector started to focus on the exploitation of local georesources with circular economy solutions based on waste recycling. The present work aims to assess both the technological feasibly of waste recycling in the clay bricks manufacturing and the effect of different degreasers on the same clay body in order to disclo...
Article
The addition of wastes to silicate ceramics can considerably expand the compositional spectrum of raw materials with a possible inclusion of hazardous components. The present work quantitatively examines relevant literature to determine whether the benefits of incorporating hazardous elements (HEs) into silicate ceramics outweigh the pitfalls. The...
Article
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Strong fluxes are needed to fire vitrified ceramics at temperatures significantly lower than those usually reached in industrial firing cycles. This work is aimed at understanding the role of strong fluxes in the microstructural evolution during sintering. Six fluxes (colemanite, ulexite, wollastonite, diopside, spodumene and phonolite) were indivi...
Article
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In the latest years, the interest about Phase Change Materials (PCM) in building applications grew in force of their capability to adsorb heat and limit in-out building heat exchanges. The main problem is how to introduce PCM into the building envelope, also in case of ventilated façades. For this purpose, a ceramic foam was studied. Two different...
Article
Full-text available
Current trends in the ceramic industry see an increasing interest on porcelain stoneware, by which is possible to produce large tiles and slabs. These products are manufactured by spray-dried powders, which have excellent technological properties but require high energy and water consumption. Dry-processed granulates allow to reduce such a consumpt...
Article
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The ceramic industry is going to be deeply involved in the transition to a circular economy. However, the main obstacle to a widespread recourse to waste recycling is the lack of knowledge about its effect in ceramic tile manufacturing. The rationale behind this work is to look at recycling from the industrialist's point of view. The goal is overvi...
Article
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The firing behaviour of five waste glasses was studied to define key parameters able to predict bloating performances in industrial lightweight aggregates production. Bloating was investigated by hot-stage microscopy and laboratory kiln experiments, also with SiC as expanding agent. In-situ and ex-situ results were contrasted to shed light on the s...
Article
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Recent trends in the raw materials market unveil a growing dependence of the European ceramic tile industry on imports from sources outside the European Union. This tendency reflects significant changes in the typologies of ceramic products, which in turn result in a modified batch design and different raw materials. Such an evolution implies an in...
Article
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In view of the transition to circular economy, the ceramic industry is searching for suitable flux substitutes. Glassy wastes are promising candidates, even though they may significantly affect the firing behaviour and particularly high temperature permanent deformations. The goal of this study is to assess the sintering behaviour of porcelain ston...
Article
Full-text available
Using spray-dried powders is widely consolidated in ceramic production, especially for porcelain stoneware tiles and slabs. However, a novel micro-granulation process can reduce the consumption of water and energy. It is based on wetting-agglomeration-drying operations that can be managed either as dry (dry-milled powders, micro-granulation) or hyb...
Article
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The advent of digital decoration has changed the technological requirements of colorants and the way they are applied onto ceramic substrates. This technological revolution has introduced additional steps in colorant production (ink micronization) and new constraints in application (ink-jet printing) that cannot be reproduced in a standard ceramic...
Chapter
Dry pressing is the preferred technology for high-volume manufacturing of powder compacts with a relatively simple geometry. Industrial processing is usually performed by uniaxial pressing or isostatic pressing. Most important steps are powder granulation, die filling, compaction, and ejection of green compacts. Powder granulation (either by spray-...
Article
Porcelain stoneware is sintered by partial vitrification through viscous flow of a liquid phase formed at high temperature. This sintering process involves a complex evolution of both phase composition and chemistry of the liquid phase, according to the dynamic equilibrium established with the residual minerals and the new crystalline phases formed...
Article
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Waste recycling has become an important issue in the environmental sustainability ofmining operations. Beneficiation of borate ores produces a boron-bearing sludge, whichutilization in ceramic manufacturing may lower the process energy demand. A case-studywas carried out on a sludge coming from the processed ore of an evaporite located at theTincal...
Article
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The shear viscosity and the glass-vapor surface tension at high temperature are crucial to understand the viscous flow sintering kinetics of porcelain stoneware. Moreover, the pyroplastic deformation depends on the viscosity of the whole body, which is made up of a suspension of crystals dispersed in the melt. The existing fundamental theoretical b...
Book
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This Profile is intended as a collection of broad information on the deposits of feldspathic raw materials and other fluxes for ceramic tiles. It encompasses a wide range of information, spanning from hints on mining history and geology of deposits, to a brief discussion of technological issues (mineral processing and ceramic use). A special attent...
Article
The progressive depletion of the main feldspathic flux deposits in the World is forcing the ceramic industry to search for suitable substitutes. The aim of this study is to assess the potential of some feldspar sources in the Egyptian Eastern Desert, particularly syenites from Abu Khruq, in the manufacture of ceramic tiles. Beneficiated samples obt...
Article
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The literature on V-doped zircon pigments offers a puzzling situation with unanswered questions about the origin of turquoise colour. In this study, new diffraction (XRPD) and spectroscopic (EPR, EAS) data were obtained on four industrial pigments, whose vanadium content is much higher than samples from previous investigations. Both EPR features an...
Article
Full-text available
Feldspathic fluxes are fundamental ingredients of many ceramic products, but little is known about the sources actually utilized by industry and the evolution over time. This paper reviews the sourcing of feldspathic raw materials over a long timespan (1971–2016) including viable substitutes (particularly recycled materials and end-of-life products...
Article
Herein we report the easy incorporation of brightly phosphorescent cationic Iridium(III) tetrazole complexes into a silica based matrix through an easily scalable colloidal process. To this purpose, two cationic Ir(III) emitters bearing 5-aryl tetrazole ligands (R-CN4) were selected: the blue [F2IrPTZ-Me]+ (C^N = F2ppy; N^N = PTZ-Me - 2-(2-methyl-2...
Article
The compaction behavior of spray-dried powders has turned into concern in porcelain stoneware manufacturing due to the increasing diffusion of large slabs. It is necessary to fill a knowledge gap between the compaction behavior with conventional presses and novel technologies. For this purpose, eighteen industrially-manufactured spray dried bodies...
Article
Cobalt-based pigments were synthesized using clinopyroxene as crystalline host. The pigments are a Ca(CoxMg1-x)Si2O6 solid solution, with x = 0.05, 0.2, 0.4, 0.5, 0.6, 0.8 Co apfu, and were synthesized from melt. The pigments were characterized by single-crystal X-ray diffraction, SEM-EDS, optical microscopy, colorimetry and optical spectroscopy. T...
Article
The technological behavior of porcelain stoneware bodies during deposition and pressing of large slabs depends on the rheological properties of spray-dried powders and the way they affect compaction. Although the literature offers some insights into the characteristics of spray-dried powders for ceramic tiles, no data are available on bodies utiliz...
Conference Paper
Full-text available
The ceramics sector in Tunisia includes 49 brick manufacturing plants, 101 artisanal bricks plants, 15 earthenware factories and 10 sanitary units. The consumption of clay in Tunisia in this activity is about 9 million tons per year distributed among the brick, earthenware, sanitary, refractory, binders and artisanal pottery sectors. Tunisia mines...
Article
(Mg,Fe)SiO3 perovskite is the most abundant mineral of the Earth's lower mantle, and compounds with the perovskite structure are perhaps the most widely employed ceramics. Hence, they attract both geophysicists and material scientists. Several investigations attempted to predict their structural evolution at high pressure, and recent advancements h...
Article
Full-text available
The aim of this study is to assess the potential as ceramic flux of some feldspar sources in the Egyptian Eastern Desert, particularly syenites from Abu Khruq, which is the most promising ring complex, taking into account various issues, including the occurrence of nepheline syenites. This late Cretaceous ring complex shows zones of alkaline rocks...
Article
Titania-functionalized ceramic tiles are gaining space on the market of the self-cleaning photocatalytic building materials after a decade of industrial attempts and investigation on different technological issues. The present paper overviews the latest research on photocatalytic ceramic tiles in terms of process parameters, durability, cleanabilit...
Article
This work aimed to characterize bentonites with different features and origins (Brazil, Argentina, Italy and United States) that were impregnated with Ag, TiO2, Pd and Au nanoparticles. Either commercial (TiO2) or synthesized (Ag, Pd and Au) nanoparticles (NP) were used and characterized by DLS and XRD. Subsequently, the dispersed NP was impregnate...
Article
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In this study, cobalt chromite (CoCr2O4) nano pigments were synthesized in a microwave oven at 180 °C for 2 h by using corresponding metal acetates in diethylene glycol media. The resulting powders (as-synthesized and calcined) were successfully characterized by X-ray diffraction, thermogravimetry–differential scanning calorimetry, fourier transfor...
Poster
Full-text available
BRICK CLAYS: FROM GENESIS TO TECHNOLOGICAL PROPERTIES
Article
In the present study metakaolin (MK), prepared by calcination of a natural tunisian kaolin at 750 °C, was mixed with different amounts of phosphoric acid (11–48 wt% P2O5) and heated at various temperatures (250, 500, 750 and 1000 °C) for 4 h. The structure of materials was characterized by X-ray diffraction, Fourier transform infrared spectroscopy,...
Article
In this work, 5 mol% Nb2O5-doped TiO2 synthesized sol was sprayed on glazed ceramic tiles. The crystallization of TiO2 nanoparticles occurs on the surface of the tiles after annealing at 600–900 °C, this innovative approach leads to a drastic decrease in the titania grain size as detected by SEM and XRD. The superhydrophilic and self-cleaning perfo...
Article
Mainly ruled by oxygen octahedral rotations, perovskite oxides can exhibit zone boundary transitions (ZBTs) either with dTc/dP>0 or dTc/dP<0. Synchrotron structural investigations at high pressure conditions place YAl0.25Cr0.75O3 orthorhombic perovskite at the boundary of ZBTs. The absence of changes in the octahedral tilting and a volume reduction...
Article
The paper studies the addition of electric arc furnace stainless steel (EAF-SS) slag to clay raw materials for ceramic brick manufacturing in order to get more sustainable materials without compromising their final properties. Different amounts (10 wt%, 20 wt% and 30 wt%) of EAF-SS slag were added to a reference clay material. The samples were proc...
Article
Several batches of porcelain stoneware were formulated by partial replacement of coarse Na and Na-K feldspars (standard batch) with quartz in two different grain sizes, micronized K-feldspar or a mixture of these components. Everyone was processed (laboratory scale) by wet and dry routes to compare: sintering curve, microstructure, phase compositio...
Article
The constant increase in consumption of aggregates for concrete production represents a major environmental issue in the construction industry. Recycled wastes might be used as raw materials in the manufacturing of artificial LightWeight Aggregates (LWAs) in substitution and/or in combination with aggregates produced using natural sources for sever...
Article
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This work deals with the development of a green and versatile synthesis of stable mono- and bi-metallic colloids by means of microwave heating and exploiting ecofriendly reagents: water as the solvent, glucose as a mild and non-toxic reducer and polyvinylpirrolidone (PVP) as the chelating agent. Particle size-control, total reaction yield and long-...
Article
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Hibonite (CaAl12O19, space group [s.g.] P63/mmc) has the structural formula A[XII]M1[VI] M2[V]M32[IV]M42[VI]M56[VI]O19, where Ca is 12-fold coordinated at site A and Al3+ ions are distributed over five different sites: three distinct octahedra [M1 (point symmetry D3d), M4 (C3v) and M5 (Cs)], the M3 tetrahedron (C3v), and the unusual fivefold coordi...
Article
Companies from different industrial sectors regularly use biological aerated filters to reduce pollutants resulting from industrial productions. These filters use a bed of inert material for the growth of a microbial colony which has the key role to break down pollutants. The inert bed is usually formed by organic or inorganic material and always m...
Article
Kaolin occurs in Patagonia as residual (weathering or hydrothermal) deposits at the surface of an extended Jurassic rhyolite province or in the upper sedimentary Cretaceous or Danian–Paleocene layers. On the same paleogeographic surface, numerous epithermal Au–Ag lodes occur, making kaolin genesis a crucial point in mining exploration. The weatheri...
Chapter
Despite the wide compositional range and the flexibility of the perovskite lattice, there are just a few successful examples of colored phases based on this crystal structure. The systems proposed in the literature as pigments encompass alkaline earth titanates – stannates – zirconates and yttrium or rare earth orthoaluminates (doped with transition...
Article
The impact resistance of ceramic tiles is an important technical requirement, especially for large size and/or low thickness slabs. The standard test for ceramic tiles (ISO 10545-5) is non-destructive: it determines the coefficient of restitution of a small sample (75×75 mm2) assembled on a concrete substrate under a weak impact energy (0.27 J). Th...
Article
Digital decoration of ceramic tiles has turned to be a prevalent and dynamic technology in the last decade. Current printers use drop-on-demand (DOD) ink-jet print heads (IJP) fed with solvent-based inks containing ceramic pigments as coloring agents. However, due to environmental constraints, water-based systems are envisaged as a green alternativ...
Article
Full-text available
Self-cleaning applications using TiO2 coatings on various supporting media have been attracting increasing interest in recent years. This work discusses the issue of self-cleaning textile production on an industrial scale. A method for producing self-cleaning textiles starting from a commercial colloidal nanosuspension (nanosol) of TiO2 is describe...
Article
Inkjet printing is increasingly used to decorate ceramic tiles, with pigmented inks in most cases. These inks are manufactured by micronizing conventional ceramic pigments down to median diameters of 0.2-0.6 µm. Although such a size reduction theoretically offers significant advantages in terms of the optical and fluid mechanical properties of the...
Article
In the last decade, the drop-on-demand (DOD) ink-jet printing has become the leading technology for the decoration of ceramic tiles. The inks employed for such application are colloidal suspensions of oxide particles (0.3 μm) whose stability (against agglomeration and over time) is fundamental to get successfully the tile decoration. Jettability fr...
Article
The crystalline growth kinetics during isothermal sintering of two nanotitania powders synthesized by similar routes, but with and without the presence of chlorine in the synthesis batch) were studied by X-ray powder diffraction and modelled by several grain growth models. Both nanopowders contained anatase as the initial titania phase with similar...
Article
The pyroxene structure was successfully used as a crystalline host for a new Co-based pink pigment. Different compositions of Ca1−xCo1+xSi2O6 (0 ≤ x ≤ 1) powders were prepared by using the solid state method with different temperatures and times of annealing. The characterization of the fired samples was performed by X-Ray Diffraction (XRD), Scanni...
Article
Drop on demand ink-jet printing is turning to be the leading technique in the decoration of ceramic tiles. This technology makes use in most cases of pigmented inks which are manufactured by micronizing conventional ceramic pigments in the 0.2–0.6 µm range (median diameter). Although significant improvements to optical properties are in theory put...
Article
One of the most important applications of nanostructured TiO2 is the manufacture of self-cleaning textiles. It is believed that the self-cleaning properties originate from the photocatalysis of water by nanostructured TiO2, but the mechanisms acting on textiles, and particularly the phenomena occurring at the interface, are not fully understood yet...
Article
Full-text available
The high-pressure behaviour of the thaumasite structure was investigated using synchrotron powder X-ray diffraction, up to 19.5 GPa. Based on Rietveld refinements, thaumasite retained the room-pressure P63 space group throughout the whole investigated pressure range while the pressure dependence of the refined unit-cell parameters can be cast into...
Article
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The isovalent substitution of chromium for aluminium at octahedral site along the Na(Al1–xCrx)P2O7 pyrophosphate solid solution has been investigated by means of the combined application of X-ray powder diffraction (XRPD) and electronic absorption spectroscopy (EAS). In agreement with the structural refinements, deconvolution of the optical spectra...