SrTiO3 crystalline nanoparticles were prepared using the microwave-assisted hydrothermal method at 140 °C with synthesis times varying from 4 to 160 min. Sample characterization showed that the method is effective in obtaining nanoparticles in a relatively short time, which have the highest photoluminescence emission. The crystalline phase of perovskite-type SrTiO3 is not significantly influenced by synthesis time. However, the SrTiO3 phase is already obtained with a 4 min synthesis time. Also, all samples exhibited photoluminescence at room temperature in the blue-green region, where intensity decreased with increasing synthesis time and particle size. The samples synthesized with the shortest time showed higher photoluminescence emission and smaller particle sizes. The morphology obtained based on FE-SEM showed cubic nanoparticles with inhomogeneous grain growth at higher temperatures of synthesis in addition to the formation of new architectures.

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Low-cost bricks were manufactured using construction and demolition waste (CDW). Lime and cement used as binding agents mixed with CDW and water. The bricks present better technological properties than standards. The use of this waste reduce the raw materials demands and environmental impacts.

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Sugarcane bagasse ash (SCBA) is an industrial waste that contains silicon and aluminum oxides as the major components and iron, calcium, magnesium, and potassium oxides as the main minor components. In this paper, SCBA from one Brazilian factory was characterized and tested for its influence on the ceramic properties of clay/ash ceramic probes. Prismatic probes were pressed (18 MPa) using a ceramic mass mixed with 0%, 5%, 8%, and 10% ash. The probes were fired at temperatures between 800° and 1200°C. X‐ray diffraction, X‐ray fluorescence, thermal analysis (differential thermal analysis, thermogravimetric analysis/differential thermogravimetric analysis), and tests for texture (particle‐size analysis), flexural strength, and linear shrinkage were carried out to characterize the samples. The results showed that the amount of ash to be incorporated will depend on mainly the composition of clay but also ash, and indicated that the clay used in this work can incorporate up to 10% weight of ash to produce solid bricks. The results also showed an improvement in ceramic/ash properties up to sintering temperatures higher than 1000°C.

O resíduo (lodo) gerado nos decantadores das Estações de Tratamento de Água (ETA) possui composição variada, de acordo com a região onde ela está localizada, com o mês de coleta e com o coagulante usado. Neste trabalho foram feitas caracterizações, física, química e mineralógica, deste lodo e ensaios tecnológicos em corpos de prova, com a finalidade de avaliar a possibilidade de incorporação deste resíduo em massa cerâmica para produção de tijolos. Retração linear, absorção de água, porosidade e massa específica aparente e ensaios de resistência à flexão em corpos-de-prova, com diferentes concentrações de lodo, foram avaliadas. Também, foi avaliado o efeito do tipo de floculante usado na ETA, sobre as propriedades dos corpos-de-prova. A análise mineralógica mostrou que estes lodos apresentaram composição parecida com as das argilas usadas pelas cerâmicas. Em geral, a adição destes materiais à massa cerâmica piorou suas propriedades, entretanto, os valores obtidos para as propriedades tecnológicas ainda permaneceram dentro dos valores limites aceitáveis para a produção de tijolos, dependendo da temperatura de queima e da concentração na mistura. O lodo obtido com floculante à base de alumínio, em geral, prejudicou mais as propriedades cerâmicas do que aqueles à base de ferro. Os resultados indicaram que o lodo de ETA pode ser incorporado à massa cerâmica para produzir material cerâmico.

This work reports the feasibility results of recycling sugar cane bagasse ash (SCBA) to produce glass-ceramic. The major component of this solid residue is SiO 2 (>89%). A 100 g batch composition containing ash, CaO and Na 2 O was melted and afterward, poured into water to produce a glass frit. The crystallization kinetic study by nonisothermal method was performed on powder samples (<63 μm) at five different heating rates. Wollastonite is the major phase in crystallization at T>970°C, and below this temperature there is a predominance of rankinite. The crystallization activation energies calculated by the Kissinger and Ligero methods are equivalent: 374±10 and 378±13 kJ/mol. The growth morphology parameters have equal values n=m=1.5 indicating that bulk nucleation is the dominant mechanism in this crystallization process, where there is a three-dimensional growth of crystals with polyhedronlike morphology controlled by diffusion from a constant number of nuclei. However, differential thermal analysis (DTA) curves on both monolithic and powder glass samples suggest that crystallization of the powder glass sample occurs through a surface mechanism.The divergence in both results suggests that the early stage of surface crystallization occurs through a three-dimensional growth of crystals, which will then transform to one-dimensional growth.

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