Production of glass-ceramics from coal ashes

Leroy, Christian; Ferro, Marta C.; Monteiro, Regina da Conceição Corredeira; Fernandes, Maria Helena

doi:10.1016/s0955-2219(00)00193-x

Cited by 89 publications

(48 citation statements)

References 11 publications

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“…As a consequence the hardness and wear resistance increased with increasing crystallisation time. The Portuguese ashes investigated by Leroy et al [99] gave melts that were too viscous to pour at 1520°C and hence 10wt%Na 2 O and 10wt%CaO (by adding pure Na 2 CO 3 and CaCO 3 ) were added to the ash to lower the viscosity. Pourable melts were obtained which were successfully transformed into glass-ceramics with esseneite (CaFeAlSiO 6 ) as the main crystalline phase formed and nepheline (NaAlSiO 4 ), as secondary phase [99,100].…”

Section: Melting and Subsequent Heat Treatmentmentioning

confidence: 99%

Glass-ceramics: Their production from wastes—A Review

2006

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Glass-ceramics are polycrystalline materials of fine microstructure that are produced by the controlled crystallisation (devitrification) of a glass. Numerous silicate based wastes, such as coal combustion ash, slag from steel production, fly ash and filter dusts from waste incinerators, mud from metal hydrometallurgy, different types of sludge as well as glass cullet or mixtures of them have been considered for the production of glass-ceramics. Developments of glassceramics from waste using different processing methods are described comprehensively in this review, covering R&D work carried out worldwide in the last 40 years. Properties and applications of the different glass-ceramics produced are discussed. The review reveals that considerable knowledge and expertise has been accumulated on the process of transformation of silicate waste into useful glass-ceramic products. These glass-ceramics are attractive as building materials for usage as construction and architectural components or for other specialised technical applications requiring a combination of suitable thermo-mechanical properties.

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Section: Melting and Subsequent Heat Treatmentmentioning

confidence: 99%

Glass-ceramics: Their production from wastes—A Review

2006

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“…From this fact, the higher strength in FA75 seems to be correlated to the extent of crystallization. The bending strength of FA75 fired at 1050 is about 3 times higher than that of marble 7) and is obviously higher than those of the commercial bricks and building tiles 5) . Therefore, the utility of the fly ash glass-ceramics is suitable for industrial buildings, external and internal wall facing and pavement materials.…”

Section: Mechanical Propertiesmentioning

confidence: 83%

Development of High Strength Fly Ash Glass-ceramics by Concrete Sludge Addition

Ikeda

Yoshikawa

Hiratsuka

et al. 2009

Journal of High Temperature Society

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A large amount of fly ash is exhausted from the thermal powder plant and it is a poisonous substance including the heavy metals and dioxin. The glass solidification is an effective method as one of the waste solidification technologies. Further, producing new materials by mixing together more than two kinds of raw materials is a more useful method. However, a number of trials are required in this method. We selected glass-ceramics with the crystal structure of an Anorthite (CaO·Al2O3 2SiO2), fly ash as inorganic wastes and concrete sludge for construction materials. It is necessary to clarify the optimum production method. Batches were prepared by mixing these raw materials with various weight ratios. Glass samples were produced by melting the batches at 1450 and quenching. They were reheated in the region of 950-1100 to make into glass-ceramic. The properties of obtained glassceramics were examined by XRD analysis, SEM observation, and some material tests for the strength, hardness, toughness, and so on. The XRD analysis and SEM observation showed that the crystallized phase of the produced glass-ceramics were identified as an Anorthite. The material tests showed that the Vickers hardness was very high, while the chemical resistance was relatively low.

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“…Tais processos ainda não são utilizados no Brasil com a mesma intensidade que em países desenvolvidos [7]. Atualmente as empresas depositam esse resíduo em terrenos licenciados por órgãos ambientais, mas estas áreas são limitadas.…”

Section: Introductionunclassified

Avaliação das propriedades físicas de revestimentos cerâmicos produzidos com resíduo da indústria cerâmica (cinza pesada de carvão mineral)

et al. 2015

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A cinza resultante da queima do carvão mineral pulverizado é um dos resíduos gerados pelas empresas produtoras de materiais cerâmicas. Quimicamente, é constituída de uma ampla mistura de óxidos, sendo os majoritários Al 2 O 3 , SiO 2 e Fe 2 O 3 e outros menores como CaO, MgO, sulfatos e outras combinações. Atualmente, em muitas empresas, a cinza produzida é aterrada em áreas licenciadas por órgãos ambientais. Com o ritmo acelerado de produção de revestimentos cerâmicos e em virtude da sua limitada vida útil é necessário a utilização de outros locais, adequados, para deposição das cinzas, medida que provoca um gasto mensal elevado. Diante deste cenário, a adição de cinza à matéria-prima, além de diminuir o impacto ao meio-ambiente, pode propiciar uma redução geral de custos, tanto pelo barateamento da produção, como pela diminuição daquantidade de cinzas a serem aterradas. Desta forma, o objetivo deste trabalho foi avaliar as propriedades físicas de revestimentos cerâmicos produzidos com a adição de cinza pesada de carvão mineral. Para sua realização, corpos de prova foram confeccionados com adição de 1 a 30% de cinza em base mássica. Os corpos de prova foram armazenados dentro de placas refratárias e queimados em forno túnel a uma temperatura de 1084ºC em um ciclo de 29 horas. Foram analisados parâmetros físicos para a barbotina e corpo de prova pós-queima. Os resultados obtidos foram comparados com os padrões estabelecidos pela norma NBR 13818. Foi demonstrado que os experimentos realizados com adição de 1 a 10 % de cinza apresentaram-se dentro dos padrões estipulados pela norma. Para porcentagens de cinza adicionada acima de 4 %, alguns valores estiveram fora dos padrões, sendo a formação de "coração negro" o parâmetro que mais se afastou das exigências da norma em questão.Palavras-chave: cinza, revestimentos cerâmicos, propriedades físicas. ABSTRACTThe ash is a solid waste generated in ceramic processing, being one of the outcomes of burning pulverized coal. The chemical composition of ash consists of a mixture of oxides, especially Al 2 O 3 , SiO 2 and Fe 2 O 3 , and other species like calcium, magnesium, sulfates or other combinations. In many companies, the residual ash is transported to landfills, which are licensed by environmental agencies. With the increasing current production of ceramic tiles, the landfills have a limited lifetime, so the companies must search for other expensive alternatives for ash deposition. Henceforth, the addition of ash to the raw material, besides contribution to reduction of the environment impact, may also reduce the total costs, by decreasing the amount of raw material demanded in process and the amount of residual ash to be deposed. So, the objective of this study was to

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Production of glass-ceramics from coal ashes

Cited by 89 publications

References 11 publications

Glass-ceramics: Their production from wastes—A Review

Glass-ceramics: Their production from wastes—A Review

Development of High Strength Fly Ash Glass-ceramics by Concrete Sludge Addition

Avaliação das propriedades físicas de revestimentos cerâmicos produzidos com resíduo da indústria cerâmica (cinza pesada de carvão mineral)

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