Ceramic porcelain stoneware production with Spanish clays purified by means of the removal of iron compounds and organic matter using physical methods

As the production of ceramic porcelain stoneware in Spain is totally conditioned by the importation of ball clays, because of the lack of adequate Spanish ball clays, this work has focused on the formulation of ceramic porcelain body from Spanish clays purified by means of physical removal processes. This method was applied to three Spanish clays containing common clay impurities of iron (hematite and siderite) and organic matter. Iron removal was carried out using the wet sieve method, the hydrocycloning method and the electromagnetic filtering method, obtaining a reduction in iron content of up to 80 wt%, while the clay containing organic matter was treated thermally at 400 °C for 30 min so as to leave it almost completely purified. These treated clays, after being characterized (chemical and mineralogical composition, plasticity, organic carbon, thermal behaviour and colour), were used in the porcelain stoneware body composition instead of imported clays, the result being a composition capable of substituting the standard porcelain stoneware formulation in terms of sintering, morphology, colour, flexural strength and dilatometry

Effect of Fluxing Additives in Iron-rich Frits and Glazes in the Fe2O3–SiO2–CaO–Al2O3 System

Glasses in the Fe2O3–SiO2–CaO system are potential candidates for many technological applications due to their ferrimagnetic and semiconductive properties, which have been extensively studied; in this sense, the effect of adding different melting additives like Li2O, B2O3, in this glass system on frits and glazes with 30–40 mass-% of Fe2O3 was studied. Ceramic frits were melted at different temperatures with subsequent cooling in water. Samples were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis and thermogravimetry (DTA, TG) and by heating microscopy. Finally, frits were applied as glazes on ceramic tiles to evaluate their capacity to adapt to the tile productive process. The frits showed low to high homogeneity (depending on the fusion temperature) and oxidation phenomena. High temperature fusion led to the crystallization of magnetite during cooling. Glaze porosity was observed after heat treatment with the presence of anorthite and hematite as crystalline phases in glazes

Potencialidad de un residuo de frita procedente del sector cerámico como materia prima para la producción de material vitrocerámico

This work consists of studying the devitrification capacity of a residue from sodium-calcium frit, using the vitreous powder sintering method, which follows the traditional ceramic processing route, including a specific heat treatment to generate the appearance of crystals from the original glass phase. Initially the frit residue has been characterized by instrumental techniques such as XRF, XRD and DTA/TG. Furthermore, the chemical analysis (XRF) has allowed the prediction of devitrification potentiality of this residue by theoretical approaches represented by Gingsberg, Raschin-Tschetverikov and Lebedeva ternary diagrams. Then, this residue was subjected to traditional ceramic method, by changing the grinding time, the pressing pressure and prepared samples were obtained at different temperatures. In this part, the techniques for measuring particle size by laser diffraction and XRD and SEM to evaluate the generated crystalline phases, were applied. Finally, it has been found that this frit residue works as glass-ceramic precursor, devitrifying in wollastonite crystals as majority phase and without being subjected to the melting step of the glass-ceramic typical method.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad Español a través del Proyecto titulado «Desarrollo de nuevos revestimientos fotovoltaicos ecológicos utilizando materiales reciclados para integración arquitectónica, basados en tecnologías de calcogenuros» (ECOART), cuyo número de expediente es RTC-2014-2294-3

Influence of treatment conditions on chalcopyrite films deposited at atmospheric pressure

Spin‐coating technique was used to deposit precursor layers for chalcopyrite films of the series CuInX2 and Cu(In,Ga)X2 where X = S or Se or (S,Se). The influence of different parameters of the process, such as solution composition, air pre‐treatment and chalcogenation treatment is discussed with respect to film applicability in photovoltaic devices. Layer morphology, stochiometry and crystalline structure varied widely with the different compositions and treatments. Highly oriented CuInSe2 and Cu(In,Ga)Se2 films were obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

Multifunctional smart coatings on novel ceramics and glassceramic substrates in the context of the circular economy

Nowadays is time of products generated by “smart coatings” that exhibit multiple functionalities. In particular, the construction industry is reached the point where it is possible to fabricate “smart and sustainable” buildings that fulfll the requirements of a growing marketplace of products and devices for “smart cities” generation. In addition, if the buildings are “green”, i.e. in accordance with the today‘s economic model “made to be made again” or so-called “circular economy” they are very attractive and viable alternative for future businesses and industrial exploring. In this concept, we report a development sustainable ceramic and glass-ceramic tile substrates made by cheap, easily accessible and recycled materials that are further functionalized by different “smart coatings” for specifc applications. Devices that generate and save energy, air and pollution cleaning, with anti-slip and phosphorescence properties are some examples of the overview that this publication described

Developing CIGS solar cells on glass-ceramic substrates

Cu(In,Ga)Se2 (CIGS) is a p-type semiconductor material and an attractive absorber for thin films solar cells due to its unique optical and electrical properties. The low cost of this technology is based on its application on ecological substrates (glass, ceramic or glass-ceramic materials), effective uses of raw materials and lower thickness of the film (range from 1.5 to 3 µm). In this work, a new glass-ceramic substrate has been developed using industrial wastes materials (recycled glass, bottom ash and fly ash from a thermal power plant) used as support in thin film solar cell technology. The CIGS absorber has been synthesized by an easy and low-cost way of preparation using the co-precipitation method. The solar cell device has been completed and fully characterized. The obtained films were characterized by X-Ray diffraction (XRD), scanning electron microscope (SEM) and electrical characterization. The short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), and total area power conversion efficiency (η) of the device are 8,11 mA/cm2, 168,2 mV, 27,6% and 0,4% respectively

Development of a glass-ceramic glaze formulated from industrial residues to improve the mechanical properties of the porcelain stoneware tiles

In this research a mixture of 90%wt of industrial residues (recycled soda-lime glass and ashes from a coalpower thermal plant) have been vitrified for their use as ‘‘secondary raw material”. Then, a glaze suspen-sion was prepared to be applied on the porcelain stoneware tile. The tested pieces have been fired by aconventional porcelain cycle at 1180 °C of maximum temperature. The XRD, XRF, SEM/EDS and thedilatometric analysis have been the instrumental techniques used to characterize the material. Finally,an ecological glass-ceramic glaze perfectly fitting on porcelain ceramic tile has been produced, exhibitinga unique phase, anorthite, which ensures a high flexural strength (around 96 MPa) and a significantVickers microhardness of 250 GPa, improving the mechanical properties of a conventional the porcelainceramic tile

Vitrification and sinter-crystallization of fly ash with glass cullet

The synthesis of a new glass-ceramic obtained by sinter-crystallization has been investigated by using soda-lime-silicate glass waste and fly ashes from a coal power thermal station located in Andorra (Teruel, Spain). An original glass as frit with composition of 50wt% recycled soda-lime glass, 25wt% bottom ash, 15wt% fly ash and 10wt% CaCO3 has been melted. After sinter-crystallization at 850ºC, it has precipitated two main crystalline phases: sodium anorthite and the hedenbergite. The linear shrinkage is 1/3 of the value of conventional porcelainized stoneware and the water absorption of this glass-ceramic is similar to a conventional porcelainized stoneware tile (less than 1wt%), being the apparent density slightly higher than this type of tiles (2.6g/cm3 instead of 2.4g/cm3 ). Flexural strength is near twice than porcelainized stoneware (around 950kg/cm2 instead of 550kg/ cm2 ) (95MPa in the new glass- ceramic with respect to 55MPa for the above mentioned as reference material)

Síntesis, caracterización y evaluación eléctrica de circonatos de bario dopados con lantánidos trivalentes

El circonato de bario es un material oxídico con estructura de tipo perovskita que muestra alta estabilidad química tanto en ambientes oxidantes como reductores, como en presencia de agua y dióxido de carbono; su conductividad ha permitido examinarlo como electrolito para celdas de combustible de óxido sólido encontrando buenos resultados, con la limitante de operar a temperaturas superiores a los 800 °C. Diversos investigadores han propuesto que es posible mejorar su conductividad eléctrica por modifi caciones en su composición química, en particular por dopaje con cationes trivalentes que reemplacen el circonio en el sitio B de la perovskita. En este estudio se sintetizó el circonato de bario por el método citrato amorfo a fi n examinar la posibilidad de obtenerlo en condiciones más favorables que las presentadas por el método de síntesis convencional (método cerámico o reacción de estado sólido). Se preparó circonato de bario dopado con europio, gadolinio, holmio, lantano, neodimio y praseodimio; la identifi cación de fases presentes se verifi có por difracción de rayos X (DRX), las propiedades eléctricas se examinaron por espectroscopía de impedancias (IS) a temperaturas entre 480 y 680 °C, con miras a evaluar su potencial uso como electrolito en celdas de combustible de óxido sólido. Los aportes de esta investigación se han centrado en el método de síntesis; en la obtención de polvos cerámicos de circonato de bario a temperaturas inferiores a las requeridas por el método cerámico; en la obtención de información química, estructural, morfológica y eléctrica de los materiales sintetizados. Se encontró la fase deseada en las condiciones de síntesis establecidas, así mismo, se aprecia un incremento signifi cativo en la conductividad de los sólidos dopados con lantano, holmio y europio en relación al material sin dopaje alguno.Barium zirconate is an oxidic material having perovskite structure that exhibits high chemical stability in both oxidizing and reducing environments, such as in the presence of water and carbon dioxide, its conductivity has led to consider it as a electrolyte for solid oxide fuel cell fi nding good results, with the limitation of operating at temperatures above 800 °C. Several researchers have proposed that it is possible to improve their electrical conductivity by changes in chemical composition, particularly for doping with trivalent cations that replace the zirconium in B site of perovskite. In this study, barium zirconate was synthetized by the amorphous citrate method to examine the possibility of obtaining in more favorable conditions than those made by the conventional method of synthesis (ceramic method or solid state reaction) conditions are synthesized. Barium zirconate doped with europium, gadolinium, holmium, lanthanum, neodymium and praseodymium was prepared, the present phase identifi cation was verifi ed by X-ray diffraction (XRD), the electrical properties were examined by impedance spectroscopy (IS) at temperatures between 480 and 680 °C in order to evaluate its potential use as a fuel cell electrolyte in solid oxide. The contributions of this research has focused on the synthesis method, in the production of ceramic powders of barium zirconate at temperatures lower than those required by the ceramic method, in obtaining chemical, structural, morphological and electrical information of material synthesized. The desired phase synthesis conditions set found, also, a signifi cant increase is seen in the solid conductivity of doped lanthanum, holmium and europium zirconate of barium in relation to the material without doping

Crystal structure of NaCd(H2PO3)3·H2O and spectroscopic study of NaM(H2PO3)3·H2O, M= Mn, Co, Ni, Zn, Mg and Cd

NaCd(H2PO3)3·H2O was synthesized in solution and its structure was studied by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system (Pbca, Z = 8) with the cell parameters: a = 9.2895(14) Å, b = 15.124(2) Å, c = 15.0592(12) Å. Final residual factors R/Rw are 0.0297/0.0790. Both Na+ and Cd2+ are octahedrally coordinated, [NaO6] and [CdO6] share edges to form zigzag chains along [1 0 0]. The 3D framework is build upon these chains which are interconnected by H2PO3 pseudo-pyramids and an intricate network of weak hydrogen bonds. NaCd(H2PO3)3·H2O belongs the series of isostructural phosphites NaM(H2PO3)3·H2O (M = Mn, Co, Ni, Zn and Mg). IR spectroscopic studies show the bands confirming the presence of the phosphite H2PO32− anion in the whole series NaM(H2PO3)3·H2O, M = Mn, Co, Ni, Zn, Mg and Cd. The UV–Vis spectroscopy was used for characterizing the d–d transitions in the Mn, Co and Ni phosphites.The financial support from Centre National de Recherche Scientifique et Technique (CNRST) (Morocco) (URAC 19). The institutional research plan No. AVOZ10100521 of the Institute of Physics and the grant “Praemium Academiae” of the Academy of Sciences of the Czech Republic