New phosphate glasses containing industrial waste and their applications for building engineering

C.L. Justino de Lima^a, F.A. Veer^b, O. Çopuroğlu^a, R. Nijsse^{a, b}

Delft University of Technology, the Netherlands
^a Department of materials, mechanics, management & design (3Md)
^b Department of Architectural Engineering & Technology

Despite a large number of products developed from waste materials, most of them consist of non-transparent applications, partly because it is a challenge to get transparent materials at reasonable temperatures from these waste products. In this work, we produced transparent glass samples incorporating slag and fly ash into a phosphate glass matrix. The compositions were adjusted in order to circumvent typical drawbacks of phosphate glasses: a high thermal expansion coefficient and low chemical durability. The use of phosphate as a glass former, instead of silicate, is a remarkable innovation, and according to the knowledge of the authors, no other work reports its utilization for building engineering purposes. These novel glasses incorporate amounts up to 35% (in weight) of blast furnace slag or fly ash. Thermal, structural and mechanical characterization were performed. The glasses possess a low melting temperature in relation to the standard soda-lime and borosilicate glasses, melting in temperatures between 1100ºC and 1350ºC. This drastic reduction of the melting temperature allows to save energy during the manufacturing process. Furthermore, the valorization of materials that would otherwise have been previously discarded reduces costs and gas emission. It contributes to fill a current appeal for a more sustainable glass manufacturing process.

Key words: Phosphate glass, fly ash, slag, industrial waste, recycling, glass