Abrasive regeneration method

Abstract

Technique to provide an abrasive regeneration method which, from a used abrasive, can recover an abrasive by an efficient method and can thereafter obtain a high-purity regenerated abrasive by a simple method. This abrasive regeneration method uses an abrasive comprising at least one type of abrasive selected from diamond, boron nitride, silicon carbide, alumina, alumina zirconia, zirconium oxide and cerium oxide. The abrasive regeneration involves a slurry recovery step (A) for recovering an abrasive slurry discharged from a polishing machine, a separation and concentration step (B) for adding an alkaline earth metal salt as an inorganic salt to the recovered abrasive slurry to aggregate the abrasive, and separating and concentrating the abrasive from a mother liquor, an abrasive recovery step (C) for recovering the separated and concentrated abrasive, and a second concentration step (D) for filter-treating the concentrated abrasive.