A method for the production of high purity potassium fluorotantalate - or high purity potassium fluoroniobate crystal and recrystallization vessel for use in the method and prepared in accordance with this method, highly pure potassium fluorotantalate - or high

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 DEG C to 90 DEG C obtained in the dissolving step at a cooling speed of T DEG C/hour until the solution temperature of the saturated solution becomes a temperature of the range of 35 to 50 DEG C, and a second cooling process of cooling the solution at a cooling speed of ÄT-18Ü DEG C/hour to ÄT-1Ü DEG C/hour from the end of the first cooling process to the solution temperature becoming a temperature of 10 to 20 DEG C. IMAGE