Method for producing recycled zirconia

Abstract

Provided is at least one of a method for producing easily grindable recycled zirconia from a zirconia sintered body and a method for recycling a zirconia sintered body, by which method the zirconia sintered body can be recycled. A method for producing recycled zirconia includes an ammonia treatment step of subjecting a zirconia sintered body to a heat treatment in an oxygen-containing ammonia atmosphere at a temperature of 800° C. or higher and 1200° C. or lower. The ammonia treatment step satisfies at least one of a condition (a) below and a condition (b) below. (a) The oxygen-containing ammonia atmosphere has an oxygen concentration of 0.3 vol % or more. (b) The oxygen-containing ammonia atmosphere has an oxygen concentration of 0.2 vol % or more, and the zirconia sintered body has a cubic phase ratio of 3.5% or more.

Dependencies are inferred from the claim text.