| 摘要 |
<P>PROBLEM TO BE SOLVED: To recover and recycle an abrasive consisting mainly of cerium oxide containing few impurities, which can be used even for polishing a synthetic quartz glass substrate for cutting-edge semiconductor applications such as a photomask and a reticle, and to repress a fear of tight supply of cerium which is a valuable rare earth metal. <P>SOLUTION: A method for recovering cerium oxide from a waste abrasive consisting mainly of cerium oxide generated by polishing a glass substrate includes (i) a step of adding an aqueous solution of a basic substance, (ii) a step of adding a precipitant to form a precipitate consisting mainly of cerium oxide, and removing the supernatant liquid, (iii) a step of adding a solution of an acidic substance to the obtained precipitate to make the precipitate weakly acidic or neutral, (iv) a step of cleaning the obtained precipitate with an organic solvent, and (v) a step of drying and pulverizing the precipitate. <P>COPYRIGHT: (C)2013,JPO&INPIT |
