Windshield-waste-driven synthesis of hydroxy sodalite

Abstract

We demonstrated the synthesis of hydroxy sodalite (HS) via a simple hydrothermal process using windshield waste as the source material. Acid-treated waste glass was directly used as the silicate precursor. The syntheses were conducted under various NaOH-precursor contents for 1, 12, and 24 h. The crystal structure and morphology of the HS were identified by X-ray diffraction and field-emission scanning electron microscopy. As per the results of the analyses, the HS and zeolite-A phases formed with low NaOH content, but HS was successfully synthesized in a single phase with a Na2O:SiO2:Al2O3 molar ratio of 2.2:1:1 over the course of 24 h. For uniform and high-purity HS crystals, the sizes of the particles of windshield waste were reduced via a highenergy milling process, and then we conducted the hydrothermal procedure under same conditions. Finally, uniformly sized HS crystals were produced with an average diameter of 3 mu m. These optimized conditions were not only scientifically valuable to understand the formation process, but this process should also accelerate windshield-waste recycling. (C) 2015 The Ceramic Society of Japan. All rights reserved.