Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile

Abstract Ceramic engobe is an intermediate layer between the substrate and the glaze of a ceramic tile. It is basically composed by plastic material, clays, and non-plastic material, feldspar and frit. Light-colored clays with good plasticity and low-fire temperature are used in ceramic engobe formulations, typically ball clays. However, these clays contain different accessory minerals, which can adversely affect the opacity and the whiteness. The use of washed kaolin, with a lower content of accessory minerals, tends to lead to higher opacity and whiteness. In addition, its mechanical activation can increase the plasticity, allowing its use as a replacement for ball clay. The aim of this study was to investigate the effect of the use of mechanically-activated kaolin to replace ball clay in an engobe employed in the production of ceramic tiles. Samples of kaolin were activated by high energy mill (1 and 4 h, at 500 rpm) and characterized by surface area and particle size measurements, crystallography, infrared spectroscopy and differential scanning calorimetry. Cylindrical specimens of four ceramic engobe formulations were submitted to splitting tensile strength and bulk density tests. The specimens were fired in a laboratory kiln and characterized through the determination of water absorption, bulk density, relative density and by reflectance spectrophotometry. Crystallographic analysis with Rietveld refinement and microstructural analysis by scanning electron microscopy were also carried out. After the high energy milling, the kaolin had less crystallinity and the specific surface area increased from 4.6 to 46.1 m2/g. The use of mechanically-activated kaolin as a replacement for ball clay in a ceramic engobe increased the mechanical strength, crystalline phase content and whiteness.

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Main Authors: Becker,E., Jiusti,J., Minatto,F. D., Delavi,D. G. G., Montedo,O. R. K., Noni Jr.,A. de
Format: Digital revista
Language:English
Published: Associação Brasileira de Cerâmica 2017
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132017000300295
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spelling oai:scielo:S0366-691320170003002952017-08-11Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tileBecker,E.Jiusti,J.Minatto,F. D.Delavi,D. G. G.Montedo,O. R. K.Noni Jr.,A. de kaolin ball clay ceramic engobe mechanical activation Abstract Ceramic engobe is an intermediate layer between the substrate and the glaze of a ceramic tile. It is basically composed by plastic material, clays, and non-plastic material, feldspar and frit. Light-colored clays with good plasticity and low-fire temperature are used in ceramic engobe formulations, typically ball clays. However, these clays contain different accessory minerals, which can adversely affect the opacity and the whiteness. The use of washed kaolin, with a lower content of accessory minerals, tends to lead to higher opacity and whiteness. In addition, its mechanical activation can increase the plasticity, allowing its use as a replacement for ball clay. The aim of this study was to investigate the effect of the use of mechanically-activated kaolin to replace ball clay in an engobe employed in the production of ceramic tiles. Samples of kaolin were activated by high energy mill (1 and 4 h, at 500 rpm) and characterized by surface area and particle size measurements, crystallography, infrared spectroscopy and differential scanning calorimetry. Cylindrical specimens of four ceramic engobe formulations were submitted to splitting tensile strength and bulk density tests. The specimens were fired in a laboratory kiln and characterized through the determination of water absorption, bulk density, relative density and by reflectance spectrophotometry. Crystallographic analysis with Rietveld refinement and microstructural analysis by scanning electron microscopy were also carried out. After the high energy milling, the kaolin had less crystallinity and the specific surface area increased from 4.6 to 46.1 m2/g. The use of mechanically-activated kaolin as a replacement for ball clay in a ceramic engobe increased the mechanical strength, crystalline phase content and whiteness.info:eu-repo/semantics/openAccessAssociação Brasileira de CerâmicaCerâmica v.63 n.367 20172017-09-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132017000300295en10.1590/0366-69132017633672077
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language English
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author Becker,E.
Jiusti,J.
Minatto,F. D.
Delavi,D. G. G.
Montedo,O. R. K.
Noni Jr.,A. de
spellingShingle Becker,E.
Jiusti,J.
Minatto,F. D.
Delavi,D. G. G.
Montedo,O. R. K.
Noni Jr.,A. de
Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
author_facet Becker,E.
Jiusti,J.
Minatto,F. D.
Delavi,D. G. G.
Montedo,O. R. K.
Noni Jr.,A. de
author_sort Becker,E.
title Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
title_short Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
title_full Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
title_fullStr Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
title_full_unstemmed Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
title_sort use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile
description Abstract Ceramic engobe is an intermediate layer between the substrate and the glaze of a ceramic tile. It is basically composed by plastic material, clays, and non-plastic material, feldspar and frit. Light-colored clays with good plasticity and low-fire temperature are used in ceramic engobe formulations, typically ball clays. However, these clays contain different accessory minerals, which can adversely affect the opacity and the whiteness. The use of washed kaolin, with a lower content of accessory minerals, tends to lead to higher opacity and whiteness. In addition, its mechanical activation can increase the plasticity, allowing its use as a replacement for ball clay. The aim of this study was to investigate the effect of the use of mechanically-activated kaolin to replace ball clay in an engobe employed in the production of ceramic tiles. Samples of kaolin were activated by high energy mill (1 and 4 h, at 500 rpm) and characterized by surface area and particle size measurements, crystallography, infrared spectroscopy and differential scanning calorimetry. Cylindrical specimens of four ceramic engobe formulations were submitted to splitting tensile strength and bulk density tests. The specimens were fired in a laboratory kiln and characterized through the determination of water absorption, bulk density, relative density and by reflectance spectrophotometry. Crystallographic analysis with Rietveld refinement and microstructural analysis by scanning electron microscopy were also carried out. After the high energy milling, the kaolin had less crystallinity and the specific surface area increased from 4.6 to 46.1 m2/g. The use of mechanically-activated kaolin as a replacement for ball clay in a ceramic engobe increased the mechanical strength, crystalline phase content and whiteness.
publisher Associação Brasileira de Cerâmica
publishDate 2017
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132017000300295
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