Effect of temperature and glass content on crystalline phases in porcelain sintered with recovered automotive glass

Abstract

In the pursuit of sustainable porcelain production, this research examines the potential of using recovered automotive glass as a substitute for traditional feldspar, specifically feldspar imported from Spain. Porcelain samples were sintered at different temperatures and with varied proportions of automotive glass. The crystalline phases formed post-sintering were determined through X-ray diffraction and quantified by dissolving the porcelain in concentrated hydrofluoric acid. Results revealed that the inclusion of automotive glass, owing to its dissolved oxide content, accelerated the porcelain melting process and led to an increase in the vitreous phase. Notably, anorthite phases became dominant and mullite formation was evident at 1100 °C, stabilizing in samples G00 and G10, and then increasing at 1200 °C due to the emergence of secondary mullite. This secondary mullite forms from the residual silica after the primary mullite formation and the aluminium in the feldspars, which is about 17 %. For samples G20 and G30, only primary mullite was observed due to the decreased aluminium content resultant from feldspar replacement by glass. These findings underscore the viability of automotive glass in porcelain production, providing a sustainable and effective alternative to feldspar.

Keywords

• Feldspars
• Crystalline phases
• Porcelain
• Mullite