RECOVERY OF DIAMOND ABRASIVE GRAIN

Japanese Patent JPH1112562

A

PROBLEM TO BE SOLVED: To recover and reuse diamond abrasive grain by subjecting a polishing slurry waste liquor containing diamond abrasive grain to centrifugation to concentrate a solid content, washing the concentrate with water and treating the concentrate with an acid to dissolve and remove a metal component. SOLUTION: A polishing slurry waste liquor containing diamond abrasive grain and a dispersant is subjected to centrifugation to concentrate a solid content containing the diamond brassiere grain. Then the concentrate is washed with water to remove the dispersant. Preferably the removal of the dispersant by washing with water is carried out by a method for suspending the concentrated solid content in water to dissolve the dispersant in water and performing a solid-liquid separation. The solid content having finished washing with water is treated with an acid, a metal component present in the content originating from a material to be polished is dissolved and separated into a liquid phase and a solid phase. The prepared solid phase is sufficiently washed with water to remove an attached acid component and to recover diamond abrasive grain hardly containing impurities. The polishing slurry waste liquor is discharged, for example, from a manufacturing process of a hard disc for magnetic recording medium.

TAWARA EIJI
SATO HIDEYUKI
OGAWA KIYOHIRO

JP17181297A

January 19, 1999

June 27, 1997

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MITSUBISHI CHEM CORP

B24B57/02; B04B1/20; C02F1/38; C09K3/14; (IPC1-7): C09K3/14; B04B1/20; B24B57/02; C02F1/38

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