Westerman, Hattori, Daniels & Adrian, LLP
Method for recovery of cerium oxide
A method for recovery of cerium oxide from the abrasive waste composed mainly of cerium oxide arising from the polishing of glass substrates, said method including the steps of (i) adding to the abrasive waste an aqueous solution of a basic substance; (ii) adding to the resulting solution a precipitant, thereby forming precipitates composed mainly of cerium oxide, and removing the supernatant liquid; (iii) adding to the resulting precipitates a solution of an acid substance, thereby making said precipitate slightly acid to neutral; (iv) washing the precipitates with an organic solvent; and (v) drying and crushing the precipitates. The method males it possible to recycle abrasive waste into a pure abrasive composed mainly of cerium oxide which can be reused to polish synthetic quartz glass substrates for state-of-the-art semiconductor technology relating to photomasks and reticles.
SHIN-ETSU CHEMICAL CO., LTD.
C C C
C09K C09G C01F
inventional inventional inventional
Masaki Harunobu Daijitsu
Takeuchi Matsui Harada