Extraction of silicon dioxide from waste colored bottles by alkali fusion using KOH or NaOH

Abstract

A process of extraction of SiO₂ from waste colored bottles was investigated, because various utilizations of waste glasses were expected by extracting SiO₂ which is the main component in the bottles. Sample solutions were prepared by alkali fusion of the crushed glasses and the hydroxide (KOH or NaOH). The solutions were boiled after mixing HCl with the solutions, and Si (OH)₄ was then precipitated. After drying the Si (OH)₄ separated from the solution, the SiO₂ powder with purity of 99.75±0.15% was obtained. In addition, the yield of the SiO₂ was also confirmed to be 97-98% by quantitative analysis. From these results, the process of extraction using KOH or NaOH was revealed to have a potential applicability as a recycling process of waste glasses.