Estimation of the heat of reaction in traditional ceramic compositions

Most energy studies on the traditional ceramic manufacturing process focus on the firing stage because this is the process stage that consumes the greatest amount of thermal energy. At present in Europe, using typical technologies, about 50% of the energy input in the firing stage is still lost through the kiln stacks. A key issue in energy studies is the accurate determination of the energy efficiency of the process, an issue that may become crucial in coming years to enable the energy management of different facilities and products to be compared. To reliably determine energy efficiency, accurate determination is required of the energy needed for the necessary physico-chemical transformations to develop in the material in the firing stage. This energy is also the only strictly unrecoverable energy, as the energy contained in other streams could, potentially at least, be partly recoverable. The present study was undertaken to develop an analytical methodology for estimating the heat of reaction of seven different traditional ceramic products, involving a broad spectrum of compositions, with peak firing temperatures ranging from 850 oC to 1200 oC. The following industrial ceramic compositions were studied: four ceramic tile compositions (red-body stoneware tile, porcelain tile, red-body earthenware wall tile, and white-body earthenware wall tile); two structural ceramics compositions (white brick and roof tile), and a porcelain tableware composition. To estimate the energy involved in the physico-chemical reactions in the firing stage, an analytical methodology was developed, based on the mineralogy data of the unfired body composition and on the enthalpy of formation of the minerals in the fired tiles. The methodology was validated by comparing the results with experimental data.This study was funded by the Valencian Institute of Business Competitiveness (IVACE)in the Competitiveness Improvement Programme through project IMAMCA/2014

Clay hydration mechanisms and their effect on dustiness

Clays are employed in a wide variety of industries such as ceramic industry, manufacture of paper, rubber, etc. In this sense, it is well known that at industrial processes in which clayey materials are used, such as ceramic industry, in order to carry out some specific stages, the wetting of clays is commonly required. Moreover, it is also long established that wetting is an appropriated measure to reduce particulate matter emissions during clays storage and handling. The present study was undertaken to assess the influence of moisture on clay dustiness because, though the complex behaviour of the clay–water system has been known since antiquity, the mechanisms involved in clay hydration and their influence on dustiness are still not well understood. To encompass a wide range of specific surface areas, three clays and a kaolin were studied. Chemical and mineralogical analysis of these four raw materials was performed and their particle size distribution, flowability, true density, plastic limit, and specific surface area were determined. Raw materials dustiness was determined using the continuous drop method. As against what might intuitively be expected, the results showed that the relationship between moisture and dustiness was quite complex and strongly related to the hydration mechanisms. In this regard, to better understand the phenomena involved in the clay hydration process, a specific methodology was developed to estimate the critical points of the clay hydration process (regarding dustiness). This methodology can be readily applied to other clays or even to materials of different nature to predict the optimum moisture and, therefore, it could be employed to propose specific measures which could entail an improvement of outdoor and indoor air quality

Environmental profile of Spanish porcelain stoneware tiles

Purpose Porcelain stoneware tile (PST) iscurrently the ceram- ic tile of greatest commercial and innovation interest. An envi- ronmental life cycle assessment of different varieties of PST was undertaken to enable hotspots to be identified, strategies tobedefined,differencesbetweenPSTvarietiestobeevaluated andguidanceforPSTmanufacturerstobeprovidedinchoosing the Environmental Product Declaration (EPD) programme that best suited their needs according to grouping criteria. Methods Analysis of previous information allowed three main parameters (thickness, glaze content and mechanical treatment) to be identified in order to encompass all PST var- iations. Fifteen varieties of PST were thus studied. The cover- age of 1 m 2 of household floor surface with the different PST varieties for 50 years was defined as functional unit. The study sets out environmental data whose traceability was verified by independent third parties for obtaining 14 EPDs of PST under Spanish EPD programmes. Results and discussion The study presents PST inventory anal- ysis and environmental impact over the entire life cycle of the studied PST varieties. The natural gas consumed in the manufacturing stage accounted for more than 70% abiotic deple- tion – fossil fuels and global warming; electricity consumption accounted for more than 60% ozo ne layer depletion, while the electricity generated by the cogeneration systems avoided signif- icant environmental impacts in the Spanish power grid mix. The variationsinPSTthickness,amountofglazeandmechanicaltreat- ments were evaluated. The PST variety with the lowest environ- mentalimpactwastheonewiththelowestthickness,wasunglazed and had no mechanical treatments. Similarly, the PST variety with the highest environmental impact was the one with the greatest thickness, was glazed and had been mechanically treated. Conclusions The PST life cycle stage with the highest envi- ronmental impact was the manufacturing stage. The main hotspots found were production and consumption of energy and raw materials extraction. Variation in thickness was a key factor that proportionally influenced almost all studied impact categories; the quantity of glaze strongly modified abiotic de- pletion – elements and eutrophication, while the mechanical treatments contributed mainly to ozone depletion. The study of all PST varieties led to the important conclusion, against the current trend, that differences among them were found to be so significant that declaring a number of PSTs within the same EPD is not directly possible, and it needs preliminary verifi- cation to ensure compliance with the product category rule

On the source inversion of fugitive surface layer releases. Part II. Complex sources

The experimental measurement of fugitive emissions of particulate matter entails inherent complexity because they are usually discontinuous, of short duration, may be mobile, and are affected by weather conditions. Owing to this complexity, instead of experimental measurements, emission factors are used to inventory such emissions. Unfortunately, emission factor datasets are still very limited at present and are insufficient to identify problematic operations and appropriately select control measures. To extend these datasets, a source inversion methodology (described in Part I of this work) was applied to field campaigns in which operation-specific fugitive particulate matter emission factors were determined for several complex fugitive sources, some of which were mobile. Mobile sources were treated as a superposition of instantaneous sources. The experimental campaigns were conducted at ports (bulk solids terminals), aggregate quarries, and cement factories, encompassing powder handling operations and vehicle circulation on paved and unpaved roads. Emission factors were derived for the operations and materials involved in these scenarios and compared with those available in the emission factor compilations. Significant differences were observed between the emission factors obtained in the studied handling operations. These differences call into question the use of generic emission factors and highlight the need for more detailed studies in this field

Effect of the raw materials processing on their dustiness

En la manipulación y/o procesado de materiales pulverulentos en la industria cerámica, uno de los riesgos más importantes desde el punto de vista ambiental y de higiene laboral es la generación de polvo ambiental. En este sentido, un parámetro de gran interés es el poder de emisión de polvo, que cuantifica la tendencia de los materiales pulverulentos a generar polvo cuando se manipulan. En este trabajo, para determinar el poder de emisión de polvo de una composición cerámica (mezcla de materias primas empleada para la fabricación de baldosas cerámicas) se ha empleado un método de caída continua. Este método se ha seleccionado por ser el que mejor representa las operaciones de manipulación de materiales pulverulentos que tienen lugar en el proceso de fabricación de baldosas cerámicas. Los resultados obtenidos muestran que el poder de emisión de polvo de una misma composición cerámica se modifica sustancialmente durante el proceso productivo dependiendo de su forma de presentación. En este sentido, la muestra procedente de la molienda vía seca presenta un elevado poder de emisión de polvo, pudiéndose reducir significativamente (> 75%) aplicando la humectación y la aglomeración. Los resultados obtenidos muestran que la presentación óptima desde el punto de vista de la minimización de la generación de polvo se alcanza en el proceso de atomización, llegándose a reducir el poder de emisión de polvo en más de un 95%.During the handling and/or processing of powdered materials in the ceramic industry, one of the most important risks regarding the environmental and occupational health is the potential generation of dust. In this regard, a parameter of great interest is the dustiness of the processed materials; this parameter quantifies the tendency of the powdered materials to generate dust when handled. In this study, to determine the dustiness of a ceramic raw material composition (mixture of the body raw materials), the continuous drop method has been used. This test apparatus was selected because it is considered to better simulate how ceramic materials are handled in the ceramic industry. The obtained results show that the dustiness of the same ceramic composition exhibits significant changes during the manufacturing process, depending on the presentation form. In this regard, the dry milling sample presents the highest dustiness, which can be significantly reduced (> 75%) applying the the moisturization and agglomeration. The obtained results also shown that the best presentation form, regarding the minimization of the dust generation, is achieved in the spray-drying process, where the dustiness is reduced by 95%

Depuración de emisiones ácidas en un horno de ladrillos que usa coque de petróleo como combustible

En el trabajo que se presenta se ha estudiado un sistema de depuración de emisiones gaseosas de compuestos ácidos basado en el uso de hidróxido cálcico como reactante y filtros de mangas como sistema separador gas-sólido. Concretamente, el sistema se ha instalado en la empresa Herederos de Márquez Villar, S. L., dedicada a la fabricación de ladrillos cerámicos. El horno estudiado utiliza como combustible gas natural (precalentamiento) y coque de petróleo micronizado (en las zonas de mayor temperatura). Operando en esas condiciones, aparte del material articulado, el contaminante más crítico para cumplir los requisitos medioambientales impuestos a la empresa en su Autorización Ambiental Integrada son los óxidos de azufre (SOx). La aplicación de estos sistemas de depuración basados en el uso de hidróxido de calcio y filtros de mangas es muy común para la depuración de compuestos ácidos (HF, HCl y SOx). En el caso de los compuestos de flúor, suelen presentar elevados rendimientos (>90%), pero según la bibliografía [1] presenta un rendimiento menor y muy variable en la depuración de compuestos de azufre (7-80%), por lo que el diseño del sistema debe realizarse de forma más detallada para obtener rendimientos adecuados que permitan cumplir las especificaciones impuestas por la normativa medioambiental. El trabajo que se presenta es fruto de la colaboración de la empresa Márquez, en cuyas instalaciones de Bailén se ha realizado el estudio; de la empresa Talleres Movigi, S.L., que ha desarrollado las actividades de diseño y construcción del sistema de depuración, y del Instituto de Tecnología Cerámica, que ha realizado la caracterización de las emisiones gaseosas y del material residual recogido en los filtros de mangas,y también ha participado en el diseño y definición de los parámetros de operación del sistema de filtración estudiadoThis work studies a system of purification of gaseous emissions of acid compounds based on the use of calcium hydroxide as a reactant and bag filters as a gas-solid separator system. Specifically, the system has been installed in the company Herederos de Márquez Villar, S.L., dedicated to the manufacture of ceramic bricks. The kiln studied uses natural gas as a fuel (preheating) and micronized petroleum coke (in the areas of highest temperature). When operating in these conditions, apart from the particulate material, the most critical pollutant to meet the environmental requirements imposed on the company in its Integrated Environmental Authorization are sulphur oxides (SOx). The application of these purification systems based on the use of calcium hydroxide and bag filters is very common for the purification of acid compounds (HF, HCl and SOx). In the case of fluorine compounds, they typically have high outputs (> 90%) but, according to literature [1], they present a lower and highly variable output in the purification of sulphur compounds (7-80%). For this reason, the design of the system must be performed on a more detailed way to achieve more appropriate outputs that comply with the specifications imposed by environmental regulations. The work presented is a collaboration of the company above mentioned, in whose facilities in Bailén the study has been carried out; the company Talleres Movigi, S.L., which has developed the activities of design and construction of the purification system, and the Institute of Ceramic Technology, which has developed the characterization of gaseous emissions and the residual material collected in the bag filters, and has also participated in the design and definition of the operating parameters of the filtration system studie

How can the European ceramic tile industry meet the EU's low-carbon targets? A life cycle perspective

Ceramic tile manufacturing is deemed to be an energy intensive industry, mainly based on combustion processes and, therefore, subject to European policies aiming at reducing greenhouse gas emissions. The “Roadmap for moving to a competitive low-carbon economy in 2050”, approved by the European Commission, calls for sectoral strategies to reduce CO2 emissions by 20% by 2020 and by 83–87% by 2050, compared to 1990 CO2 emissions. This study included up to 17 technological alternatives and their combination, resulting in 25 technological scenarios associated to the life cycle of porcelain stoneware tiles. In this regard, a high parametrized LCA model was developed to allow for the required flexibility. The scenario analysis can be used: a) to estimate the degree of technological innovation required; b) to define and to focus strategies and; c) to devise the lines of technological development that need to be implemented in the ceramic tile manufacturing sector in the coming years. The alternatives consisted of endogenous and exogenous sectoral technologies. The technologic alternatives involved changes in product design (thickness and decoration), changes in the manufacturing process (preparation of raw material by dry or wet route, and simultaneous implementation of thermal energy efficiency techniques), and changes in the energy sources (hybrid and/or electric driers, and kilns and decarbonization of the power grid mix). It was clearly proven that the wider the scope of the Life Cycle Assessment study is, the greater eco-innovations are necessary. In all the studied scenarios, the manufacturing stage was always the most significant from the global warming point of view. Finally, regarding the achievability of EU objectives, the results of this study show that the implementation of widespread technologies suffice for fulfilling 2020 targets; nevertheless, only some limited combinations of both widespread and ambitious breakthrough technologies may achieve the 2050 reduction targets

Environmental development of the Spanish ceramic tile manufacturing sector over the period 1992–2007

The Spanish tile manufacturing sector has grown steadily over the years covered by the three benchmark studies, carried out in 1992, 2001, and 2007, from which data are compared in this paper. In that period, production output doubled, although since the last study was published, the situation has undergone a radical change and current production output stands at a level similar to that of 1995. Nevertheless, despite the world economic crisis, which has also severely impacted the ceramic wall and floor tile sector, it is worth noting that the sector’s environmental parameters have demonstrated a constant and positive trend, both in companies’ individual environmental performance and in the actual manufacturing processes itself. To a large extent, this situation was forced upon the sector as it had to adapt to numerous environmental regulations, which in general terms call for harsher and more stringent conditions than before. In this sense, the adoption of IPPC regulations, which affect practically the entire ceramic tile sector, and the approval of EU Directive 2003/87 establishing a scheme for greenhouse gas emission allowance trading were significant factor

La evolución energética del sector español de baldosas cerámicas

El presente texto analiza cómo ha ido evolucionando el consumo y la eficiencia energética de la industria española de baldosas cerámicas durante el siglo XX, y explora las posibilidades que se le plantean en el siglo XXI. Durante el pasado siglo este sector industrial acometió tres transiciones radicales al pasar de los combustibles tradicionales de biomasa a los hidrocarburos líquidos (fuelóleo y gasóleo), y posteriormente a los gaseosos, principalmente gas natural. Aunque la información que permite evaluar de manera fiable la eficiencia energética real en las plantas de fabricación no es fácil de obtener, los datos disponibles indican que se ha llegado a una elevada eficiencia con las tecnologías productivas actualmente utilizadas. Por tanto no se prevén cambios importantes en este aspecto, aunque siguen realizándose esfuerzos encaminados a reducir el consumo de energía en el proceso productivo. Sin embargo, los impactos y las regulaciones medioambientales, y nuevas posibles fuentes energéticas basadas en biomasa agrícola pueden abrir paso a nuevas vías de suministro energético en el sector cerámico español de baldosas

Strategic environmental communication tools

Ponència presentada a QUALICER'14, XIII Congreso Mundial de la Calidad del Azulejo y del Pavimento Cerámico, celebrat a Castelló, 17-18 febrer 2014The Instituto de Tecnología Cerámica (ITC), pursuing its programme of actions aimed at transferring knowledge to the ceramic industry, presents the following work to facilitate the entry of ceramic coverings to markets demanding sustainable or green products and to national and international sustainable building certification programmes. At present, for the industry in general and for the ceramic industry in particular, companies seeking to respond to green market demands face serious difficulties owing to the vast number of existing certificates, ecolabellings, and eco-features, which adversely affect the decision-taking process in this sense. In this context, ITC has focused on developing, adapting, and fine-tuning a series of the most demanded eco-features, currently deemed the most complete for ceramic coverings