摘要:
It is an object to provide a product having a good crystal particle size distribution of a high-purity potassium fluorotantalate crystal or a high-purity potassium fluoroniobate crystal without using a physical method for particle classification. To that end, a method for manufacturing a high-purity potassium fluorotantalate crystal or a high-purity potassium fluoroniobate crystal is used, wherein the recrystallizing step comprising a first cooling process of cooling a saturated solution with a temperature of 60° C. to 90° C. obtained in the dissolving step at a cooling speed of T° C./hour until the solution temperature of the saturated solution becomes a temperature of the range of 35 to 50° C., and a second cooling process of cooling the solution at a cooling speed of [T−18]° C./hour to [T−1]° C./hour from the end of the first cooling process to the solution temperature becoming a temperature of 10 to 20° C.