The recycling of waste glasses from TV-PC cathodic tube and screen has become very important, due to the impressive increase in the production of these wastes because they need to be reused avoinding landfilling. For the flexibility of the tilemaking process and for the large amount of liquid phase developed during firing, a potential recycling field for these waste glasses is the traditional ceramic production. In particular, both cathodic tube and screen glasses cannot be recycled in the glass industry and so they were added to a porcelain stoneware body, in percentages of 5 and 10 wt%, as a partial substitute of sodic feldspar. The aim of this study is to propose a recovery option environmentally and economically interesting of this kind of waste in the widespread ceramic tile production, without modifying process conditions and product properties. The rationale was the appraisal, simulating the tilemaking process at a laboratory scale, whether the waste glass additions change technological or mechanical properties of both fired and unfired tiles, through a comparison with a waste-free porcelain stoneware mixture. In order to comprehend the effect of recycling glasses on the fired products, particular attention was paid to sintering behaviour, microstructure, phase composition, chemical-physical properties of the liquid phase formed at high temperature. The introduction of the waste glass does not remarkably change the technological behavior during grinding, pressing and drying, and has no relevant influence on both technical requirements and colour of the final products. However, the most evident effect is represented by an increase of closed porosity, proportional to the waste content, which does not affect the mechanical strenght but could worsen the stain resistance of polished tiles. These results suggest that porcelain stoneware tiles can be a suitable use for the PC-TV glass.
Effect of waste glass (TV/PC cathodic tube and screen) on technological properties and sintering behaviour of porcelain stoneware tiles
M Dondi;G Guarini;M Raimondo;C Zanelli;
2005
Abstract
The recycling of waste glasses from TV-PC cathodic tube and screen has become very important, due to the impressive increase in the production of these wastes because they need to be reused avoinding landfilling. For the flexibility of the tilemaking process and for the large amount of liquid phase developed during firing, a potential recycling field for these waste glasses is the traditional ceramic production. In particular, both cathodic tube and screen glasses cannot be recycled in the glass industry and so they were added to a porcelain stoneware body, in percentages of 5 and 10 wt%, as a partial substitute of sodic feldspar. The aim of this study is to propose a recovery option environmentally and economically interesting of this kind of waste in the widespread ceramic tile production, without modifying process conditions and product properties. The rationale was the appraisal, simulating the tilemaking process at a laboratory scale, whether the waste glass additions change technological or mechanical properties of both fired and unfired tiles, through a comparison with a waste-free porcelain stoneware mixture. In order to comprehend the effect of recycling glasses on the fired products, particular attention was paid to sintering behaviour, microstructure, phase composition, chemical-physical properties of the liquid phase formed at high temperature. The introduction of the waste glass does not remarkably change the technological behavior during grinding, pressing and drying, and has no relevant influence on both technical requirements and colour of the final products. However, the most evident effect is represented by an increase of closed porosity, proportional to the waste content, which does not affect the mechanical strenght but could worsen the stain resistance of polished tiles. These results suggest that porcelain stoneware tiles can be a suitable use for the PC-TV glass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
