Recycle of Ceria-Based Glass Polishing Powder Using NaOH Solution

Kazuhiro KATO*†, Toshiaki YOSHIOKA and Akitsugu OKUWAKI

Department of Applied Chemistry, Graduate School of Tohoku University; 07 Aoba, Aramaki, Aoba-ku, Sendai-shi 980-8579 Japan
Present address: Fukushima Technology Centre; 1-12, Machiikedai, Koriyama-shi 963-0215 Japan

Recycle of ceria-based glass polishing powder was investigated. A waste polishing powder was treated in a 4 mol kg−1 NaOH solution with a waste/NaOH weight ratio of 1 at 60 °C, and SiO2 and Al2O3 impurities were dissolved into the solution and removed from the polishing powder. A solution which containing the impurities was heated to 100 °C, and hydroxysodalite (Na8(AlSiO4)6(OH)24H2O) was precipitate. Thus the glass polishing powder can be regenerated and hydroxysodalite was obtained as a by-product, and excess NaOH solution was reused. However addition of Si source, such as sodium silicate was required to control the leaching and precipitation process.

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