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ESTUDO DAS PROPRIEDADES DE VIDRADOS OBTIDOS A PARTIR DE RESÍDUOS INDUSTRIAIS – EFEITO DA COR E RESISTÊNCIA AO ATAQUE QUÍMICO
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O vidrado é um revestimento vítreo aplicado em peças cerâmicas para melhorar as suas pro-
priedades estéticas e funcionais. Este trabalho visa o desenvolvimento e a produção de fritas
e vidrados cerâmicos utilizando casco verde (CV) reciclado e três tipos de resíduos industriais:
escória de aciaria (SS), pó de xisto e de basalto, em proporções de 5% e 15% em peso. Os
vidrados obtidos foram aplicados em dois tipos de chacotas, TVM e Terracota, de modo a
estudar o seu revestimento. A difração de raios-X (DRX) confirmou a amorficidade de todos as
amostras fundidas, verificando-se a formação de fases cristalinas nos vidrados crus. A análise
granulometria, realizada através de difração a laser, evidenciou uma granulometria bastante
fina das fritas e do vidrado 5%SS cru comparativamente com os demais vidrados. Por análise
térmica diferencial (DTA), verificou-se que o aumento de Al2O3 no vidrado 15%SS cru, torna-o
mais refratário aumentando a temperatura de transição vítrea (Tg) e a temperatura de cris-
talização (Tp). Pelo método de indentação Vickers, obteve-se uma dureza ligeiramente inferior
nos vidrados crus, que pode dever-se à sua opacidade. O cálculo da porosidade permitiu cons-
tatar que a chacota TVM apresenta uma porosidade superior, 29,5%, permitindo uma melhor
adesão do vidrado à sua superfície. Através da colorimetria concluiu-se que a adição de SS
resulta num escurecimento da coloração dos vidrados, devido ao aumento de Fe₂O₃ na com-
posição. Foi estudada a resistência ao ataque químico em soluções de detergente ácido e bá-
sico, onde se verificou um aumento na variação de massa nas superfícies vidradas. Por micros-
copia ótica, verificou-se o aparecimento de cristais nos vidrados crus e que os mesmos se
desenvolvem com o acréscimo de SS. O ensaio de viscosidade constatou que de todos os
vidrados, o 5%SS cru apresenta a menor viscosidade a baixas velocidades de corte, uma vez
que é o vidrado que possui a granulometria mais fina. Analisou-se a viscosidade das fritas e
vidrados e concluí-se que um incremento de SS diminui a viscosidade.
The glaze is a vitreous coating applied to ceramic pieces to enhance their aesthetic and functional properties. This work aims to develop and produce frits and ceramic glazes using recycled green glass (CV) and three types of industrial waste: steel slag (SS), shale powder and basalt powder, in weight proportions of 5% and 15%. The resulting glazes were applied to two types of ceramic bodies, TVM and Terracotta, in order to study their coating. X-ray diffraction (XRD) confirmed the amorphous nature of all the fused samples, while crystalline phases were observed in the raw glazes. Granulometry analysis, performed by laser diffraction, revealed a much finer particle size distribution in the frits and 5%SS raw glaze compared to the other glazes. Differential thermal analysis (DTA) revealed that the increase in Al₂O₃ in the 15% SS raw glaze made it more refractory, raising the glass transition temperature (Tg) and the crystalliza- tion temperature (Tp). Vickers indentation testing indicated a slightly lower hardness in the raw glazes, which may be attributed to their opacity. Porosity calculations revealed that the TVM ceramic body has a higher porosity, 29,5%, allowing for better adhesion of the glaze to its surface. Colorimetry analysis concluded that the addition of SS results in a darkening of the glaze color, due to the increased Fe₂O₃ content in the composition. The chemical attack resis- tance was tested in acidic and basic detergent solutions, where an increase in mass variation was observed on the glazed surfaces. Optical microscopy showed the appearance of crystals in the raw glazes, which develop with increasing SS content. Viscosity testing of the suspensi- ons indicated that among all the glazes, the 5% SS raw glaze exhibits the lowest viscosity at low shear rates, as it has the finest particle size distribution. The viscosity of the frits and glazes was analyzed, and it was concluded that an increase in SS reduces the viscosity.
The glaze is a vitreous coating applied to ceramic pieces to enhance their aesthetic and functional properties. This work aims to develop and produce frits and ceramic glazes using recycled green glass (CV) and three types of industrial waste: steel slag (SS), shale powder and basalt powder, in weight proportions of 5% and 15%. The resulting glazes were applied to two types of ceramic bodies, TVM and Terracotta, in order to study their coating. X-ray diffraction (XRD) confirmed the amorphous nature of all the fused samples, while crystalline phases were observed in the raw glazes. Granulometry analysis, performed by laser diffraction, revealed a much finer particle size distribution in the frits and 5%SS raw glaze compared to the other glazes. Differential thermal analysis (DTA) revealed that the increase in Al₂O₃ in the 15% SS raw glaze made it more refractory, raising the glass transition temperature (Tg) and the crystalliza- tion temperature (Tp). Vickers indentation testing indicated a slightly lower hardness in the raw glazes, which may be attributed to their opacity. Porosity calculations revealed that the TVM ceramic body has a higher porosity, 29,5%, allowing for better adhesion of the glaze to its surface. Colorimetry analysis concluded that the addition of SS results in a darkening of the glaze color, due to the increased Fe₂O₃ content in the composition. The chemical attack resis- tance was tested in acidic and basic detergent solutions, where an increase in mass variation was observed on the glazed surfaces. Optical microscopy showed the appearance of crystals in the raw glazes, which develop with increasing SS content. Viscosity testing of the suspensi- ons indicated that among all the glazes, the 5% SS raw glaze exhibits the lowest viscosity at low shear rates, as it has the finest particle size distribution. The viscosity of the frits and glazes was analyzed, and it was concluded that an increase in SS reduces the viscosity.
Descrição
Palavras-chave
Vidrado cru Vidrado fundido Escória de aciaria Chacota Colorimetria Ataque químico