Balanço energético de um forno túnel de cerâmica estrutural convertido de lenha para gás natural

In energy systems, the balance of entrances, exits and losses are fundamental to rationalize the energy consumption, independently of the source (sun, natural gas, wind, water, firewood or oil). This estimate is important so much in the phase of project of the facilities, as in the exploration or operation. In the project phase it indicates the energy needs of the process and the contribution of the energy in the cost of the product and the capacity of storage of the fuel and in the operation phase it allows to evaluate the use of the energy in the process of it burns, showing the weak points that should suffer intervention to improve the efficiency. With this tool, it can be implemented routines of calculation of thermal balances in ovens of it burns of structural ceramic, in way to generate an optimized mathematical model for application in the current and promising structural ceramic brazilian industry. The ceramic oven in study is located in the metropolitan area of Natal (Rio Grande do Norte) and it is a continuous oven of the type wagons tunnel, converted of firewood for natural gas and it produces blocks of red ceramic. The energy balance was applied in the oven tunnel before and after the conversion and made the comparisons of the energy efficiencies (it burns to the firewood and it burns to natural gas), what showed that the gaseous fuel is more efficient when we burn structural ceramic in ovens tunnels. When we burn natural gas, the requested energy is smaller and better used. Tests were accomplished in the burned product that showed the best quality of the burned brick with natural gas. That quality improvement makes possible to accomplish new interventions for the most rational use of the energy in the oven tunnel of the Ceramic in study and in the industries of structural ceramic of the whole Brazil, that need control tools of burning and of quality

Análise da adição de resíduo oriundo do tratamento de esgotos em massa cerâmica utilizada para fabricação de telhas

Sludge of Wastewater Treatment Plants (WTPs) disposal is a problem for any municipality, for this reason the amount of sludge production is now a key issue in selecting treatment methods. It is necessary to investigate new applications for this waste type, due to the restrictions imposed by the environmental organs. The raw materials used in the Red Ceramic, are generally very heterogeneous, for this reason, such materials can tolerate the presence of different types of wastes. In Rio Grande do Norte, the roof tiles production corresponds to 60,61% from the total of ceramic units produced. Due to the importance of the ceramic industry of roof tiles for the state, allied to the environmental problem of the sludge disposal, this work had for objective to verify the possibility of the incorporation of sewage sludge in ceramic body used for production of roof tiles. In the research, sludge originating from drying beds of WTP of the Central Campus from UFRN and clays originating from a ceramic industry from Goianinha/RN were used. The raw materials were characterized by techniques of: analysis of particles distribution by diffraction to laser; real density; consistence limits; chemical analysis by X-ray fluorescence; mineralogical analysis by X-ray diffraction; organic matter; and solids content. Five batches of roof tiles were manufactured in the approximate dosages of 2%, 4%, 6%, 8% and 10%. To evaluate the properties of each final product, tests of water absorption, impermeability, bending strength, leachability and solubility were accomplished. The roof tiles manufactured with sludge presented characteristics similar to the roof tiles without sludge in relation to the environmental risk. The results showed that it is possible to use approximately up to 4% of sludge in ceramic bodies for production of roof tiles. However, it is observed that the high amount of organic matter (71%) present in the sludge is shown as factor that limits the sludge incorporation in ceramic bodies, worsening the quality of the roof tiles. It is necessary the use of mixtures of different raw materials under point of view of the granulometry and of the other chemical and mineralogical properties for the obtaining of a satisfactory mass to the production of ceramic roof tiles

Nucleation kinetics of crystalline phases from a kaolinitic body used in the processing of red ceramics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reuse of sugarcane bagasse ash (SCBA) to produce ceramic materials

Sugarcane bagasse ash (SCBA) is a residue resulting from the burning of bagasse in boilers in the sugarcane/alcohol industry. SCBA has a very high silica concentration and contains aluminum, iron, alkalis and alkaline earth oxides in smaller amounts. In this work, the properties of sintered ceramic bodies were evaluated based on the concentration of SCBA, which replaced non-plastic material. The ash was mixed (up to 60 wt%) with a clayed raw material that is used to produce roof tiles. Prismatic probes were pressed and sintered at different temperatures (up to 1200 degrees C). Technological tests of ceramic probes showed that the addition of ash has little influence on the ceramic properties up to 1000 C. X-ray diffraction and thermal analysis data showed that, above this temperature the ash participates in the sintering process and in the formation of new important phases. The results reported show that the reuse of SCBA in the ceramic industry is feasible. (C) 2011 Elsevier Ltd. All rights reserved.

Recycling of glass cullet as aggregate for clays used to produce roof tiles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sol-gel synthesis and characterization of Fe(2)O(3) center dot CeO(2) doped with Pr ceramic pigments

Undoped x center dot alpha-Fe(2)O(3) y center dot CeO(2) and doped with praseodymium ceramic pigments were obtained by the sol-gel method after heat treatment at 800 degrees C for 2 h. These pigments were characterized by XRD, nitrogen adsorption, scanning electron microscopy, ultraviolet-visible absorption spectroscopy and colorimetrical measurements. Red and brown colors with several tonalities were observed after changes with Ce and Pr concentration.

Estudo comparativo das argilas das olarias dos municípios de Alfenas e Areado, MG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Programa de apoio à legalização mineral de olarias da região de Rio Claro (SP)

Esse artigo apresenta os resultados de um projeto denominado de Projeto Parceria, desenvolvido no período de 2007 a 2010, com objetivo de orientar, tecnicamente, os oleiros associados da ASCER, para a correta condução das atividades de extração de matéria-prima das jazidas utilizadas pela indústria oleira. As atividades desenvolvidas, nesse projeto, contemplam a legalização da situação minerária das atuais áreas de extração, orientação em relação à recuperação das áreas degradadas pela mineração e caracterização cerâmica dos materiais argilosos utilizados na produção de tijolos. Fizeram parte desse estudo quatorze Olarias situadas na região de Rio Claro (SP). A legalização das atividades de extração mineral, na área da jazida de cada olaria, conduziu, automaticamente, à legalização ambiental, que está sendo atualmente executada. Duas olarias não puderam regularizar as suas extrações, pois as áreas de suas propriedades estavam oneradas no DNPM. Outras duas olarias não possuíam documentações referentes à parte jurídica das empresas, necessárias para legalização de suas áreas. Os materiais argilosos utilizados pelos oleiros foram caracterizados quanto às suas aplicações cerâmicas como material nobre para a fabricação de telhas e tijolos, gerando produtos de alta qualidade.

Viabilidade de aplicação das coberturas argilosas da região de Alfenas na indústra cerâmica

The region of Alfenas, in the state of Minas Gerais, Brazil, is predominantly constituted of Pre-Cambrian rocks with well developed alteration profiles in association with colluvial and alluvial sediments. No study to date has examined in detail its potential use in the ceramic industry. The scarce knowledge of its mineralogical and technological properties limits its value and consequently its industrial use. Until now, these clay materials have been used in a rudimental manner, in small scale in the fabrication of red tiles. The present study aimed at analyzing these clays mineralogically (X-ray diffraction), chemically (major and minor elements by X-ray fluorescence and organic carbon analysis) and technologically (pressing granulometric distribution; mechanical resistence; water absorption, apparent porosity; linear firing shrinkage; color of firing and others) in order to better understand the raw material and develop adequate technological applications. The best results of ceramic properties were the samples with higher organic content (more plastic clays) and higher values of Al2O3 (kaolinite and gibbsite) and Fe2O3 as well lower SiO2 content and finer grain size which contribute to a better sinterization.

Estudo e avaliação do uso de resíduos do processo Bayer como matéria-prima na produção de agregados sintéticos para a construção civil

A grande quantidade de resíduos sólidos, oriundos da indústria de mineração e metalurgia, constitui um sério problema sócio-ambiental. As características físicoquímicas destes resíduos despertam grande interesse para outras indústrias. A indústria cerâmica pode ser uma interessante consumidora da maioria deste material, para suprir a grande escassez das reservas de matérias-primas atual. Neste contexto, este trabalho mostra os estudos realizados para a reciclagem da lama vermelha, como matéria-prima na produção de agregado sintético, visando à construção civil. A lama vermelha, principal rejeito industrial da fabricação de alumina, mostrou-se um insumo de grande interesse na fabricação de diferentes tipos de agregado para ser utilizado na produção de concreto, para a construção civil. Pelas suas características físico-químicas e a grande quantidade que é produzida anualmente (cerca de 10.000.000 t em duas fábricas, só no Norte do Brasil). Estudos realizados neste trabalho mostram a possibilidade de fabricação de agregados, com diferentes propriedades e possibilidades de aplicação, na indústria da construção civil. Estas propriedades dependem do controle de parâmetros, como o teor de sílica livre e argila, a granulometria e a temperatura de sinterização. Tais variáveis permitem controlar perfeitamente a formação de fase vítrea que é a responsável pelas propriedades dos agregados como: porosidade, resistência mecânica e densidade. Este material pode ser utilizado em concreto convencional ou em concretos especiais, para atender a demanda da construção civil.

Modelo de simulação computacional para balanceamento de linhas de produção das empresas cerâmicas de São Miguel do Guamá: um estudo de caso

O presente trabalho vem apresentar um modelo de simulação computacional com propósito de resolver o problema do balanceamento de linhas de produção de uma fábrica de cerâmica vermelha, pertencente ao polo oleiro-cerâmico de São Miguel do Guamá. Neste sentido, inicialmente é realizada uma pesquisa bibliográfica acerca dos sistemas de eventos discretos, dos métodos de solução para balanceamento de linhas e dos conceitos envolvendo a modelagem e simulação. A metodologia aborda o estudo de caso, sendo este conduzido pelo método proposto por Chwif (1999) no qual abrange 03 (três) macros etapas na condução de um projeto de simulação, sejam a etapa de concepção, implementação e etapa de análise. Com o modelo computacional desenvolvido com base nas características atuais da linha de produção, pode-se descrever o estado atual do processo, identificar a operação gargalo bem como encaminhar propostas de melhorias a partir da construção de 03 cenários. Onde o terceiro cenário apresentou os melhores resultados e, portanto, sendo este o modelo representativo ao balanceamento. Ao final, entende-se como principais contribuições deste trabalho o fato de trazer para dentro da universidade a experiência da aplicação prática da simulação, envolvendo uma indústria de cerâmica vermelha de São Miguel do Guamá e oferecer a indústria desta região uma ferramenta potencial para melhoria de seus processos produtivos.

Comportamento de blocos cerâmicos estruturais produzidos a partir da mistura de lama vermelha e argila

A utilização de novas técnicas de aproveitamento de resíduos tem-se tornado cada vez mais importante na construção civil, principalmente quando se trata da utilização de resíduos de outros segmentos industriais e da redução de consumo de matérias-primas naturais. O objetivo deste estudo foi avaliar a utilização da lama vermelha, resíduo proveniente da produção de alumina metalúrgica, na produção de blocos cerâmicos vazados estruturais. A produção dos blocos foi realizada em uma indústria cerâmica, a partir de uma mistura de 60% de lama vermelha (LV) e de 40% de argila. Após a produção dos blocos, realizaram-se ensaios de acordo com as normas técnicas, tais como absorção de água e compressão axial simples. A partir da análise dos resultados, observou-se que os blocos estruturais produzidos a partir da mistura de LV e argila atenderam aos parâmetros normativos quanto ao índice de absorção de água e de resistência à compressão, e que as resistências médias e características desses blocos foram superiores às dos blocos cerâmicos de referência.

Study of ceramic block manufacture with the addition of waste from iron ore extraction

This work is intended to study the possibility of adding an amount of waste from iron mining in the ceramic mass. Clay and coal, from Vale do Paraiba, Sao Paulo, Brazil, were used in this research. These raw materials are used in the ceramic block manufacture. Clay and waste were analyzed by X-ray fluorescence and X-ray diffraction, particle size, differential thermal and thermogravimetric analysis. Liquid limit and plasticity index tests were performed in order to determine the amount of waste that which should be used in the ceramic mass. After determining the amount of waste, all samples were uniaxially pressed and sintered at 900 degrees C. Surface roughness measurements, apparent porosity and bulk density technique and three-point flexural tests were also performed to characterize the samples. The results showed that by adding the exact amount of waste, which was determined by the essays, it is possible to manufacture solid bricks.

The Change from Red to White Meat: The Role of Technology

Since 1950, the composition of the U.S. meat diet has shifted markedly from red meats to poultry. For example, from 1970 to 1984, on a percapita basis, beef consumption has declined by 6.4 percent, while chicken and turkey consumptions have increased by 37.9, and 42.5 percent respectively (U.S. Department of Agriculture, 1985). The numerous studies of this phenomenon from the demand side (Chavas, 1983; Braschler, 1983; Nyankori and Miller, 1982; Moschini and Meilke, 1984; Wohlgenant, 1985, Thurman, 1987; Chalfant and Alston, 1988) have failed to achieve a consensus as to whether a change in taste contributed to this shift. One reason for the lack of consensus is that the very large price and quantity changes make it difficult to establish whether consumers are on a new indifference map. But there have been no comparable studies of the nature and causes of the technological change that has made these large consumption and price changes possible. A decrease in the relative price of poultry with respect to red meat is in any case a major explanation of recent shifts in meat consumption patterns. The main reason for such a decrease appears to be a higher rate of technical progress in the poultry industry than in the red meat industry. Substantial productivity gains in both the production and marketing of poultry over the last two decades appears to have been translated into lower retail prices for poultry. Although some productivity gains have taken place in the red meat industry, they have not matched the cost reductions in the poultry industry (Chavas, 1987). Thus, a consumption shift from beef to poultry could possibly be interpreted as a response to changing relative prices, the structural change having occurred in the meat industry. This would imply that, if the beef industry desires to maintain or expand its market, it should seek a decrease in the production and marketing costs of beef.

Carboxymethyl lignin as stabilizing agent in aqueous ceramic suspensions

Identifying new uses for residues of industries that process large quantities of biomass, as in bioethanol production, is essential for a sustainable development with reduced impact on the environment, which is the reason why many efforts have been devoted to find noble uses for lignins. in this study, a lignin obtained from sugarcane bagasse in a bioethanol producing plant was carboxymethylated to yield the water-soluble carboxymethyl lignin (CML), which was then used as stabilizing agent in aqueous alumina (Al2O3) suspensions. CML had a degree of substitution 0.46 +/- 0.01, in relation to the C9 unit of lignin, and behaved as a polyelectrolyte in a large pH range owing to the dissociation of carboxylic groups. The action of CML as stabilizing agent of alumina aqueous suspensions was investigated using viscometry, zeta potential, and photon correlation spectroscopy (PCS) measurements, mainly as a function of pH and time. Overall, the results showed that CML had a good performance as a deflocculating agent, because it led to dispersions with low viscosity and small change in particle size as a function of time. The positive effect from the addition of CML was confirmed in the morphological features of the material obtained from the alumina suspensions after elimination of water, as indicated by scanning electron microscopy. The stabilization of alumina suspensions afforded by CML opens the way for similar applications of modified lignins, whose electrical and structural properties may be tuned for specific uses in various industries, including the ceramic industry. (C) 2011 Elsevier B.V. All rights reserved.