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 adding to the abrasive waste an aqueous solution of a basic substance ; adding to the resulting solution a precipitant , thereby forming precipitates composed mainly of cerium oxide , and removing the supernatant liquid ; adding to the resulting precipitates a solution of an acid substance , thereby making said precipitate slightly acid to neutral ; washing the precipitates with an organic solvent ; and 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 .