METHOD OF TREATING SILICON WAFER POLISHING WASTE LIQUID AND ABRASIVE

摘要

PROBLEM TO BE SOLVED: To provide a method of effectively regenerating, with high purity, a used abrasive which is contained in a silicon wafer polishing waste liquid including melted Al2O3 and ZrSiO4 as major components and an abrasive regenerated thereby. SOLUTION: A silicon wafer polishing waste liquid is separated into a solid abrasive and a solution by means of a vacuum type drum filter 1 and the solid component including a mixture of Al2O3 and ZrSiO4 as major components is dispersed in water in a dispersing bath 2 to remove rough foreign matters by a screen 3. The solid component is then separated into the abrasive and silicon by a wet screen 5 which are again dispersed in water to remove iron by an iron removing apparatus 7 followed by being dryed by a drying apparatus 8 and the particle size's being adjusted by a vibrative screen 9 to give an inexpensive abrasive having reliable quality in a high yield.