METHOD FOR PRODUCING HIGH PURITY POTASSIUM FLUOROTANTALATE CRYSTAL OR HIGH PURITY POTASSIUM FLUORONIOBATE CRYSTAL AND RECRYSTALLIZATION VESSEL FOR USE IN THE METHOD FOR PRODUCTION, AND POTASSIUM FLUOROTANTALATE CRYSTAL OR HIGH PURITY POTASSIUM FLUORONIOBATE CRYSTAL PRODUCED BY THE METHOD FOR PRODUCTION

摘要

A method for producing high purity potassium fluorotantalate crystals or high purity potassium fluoroniobate crystals, characterized in that a recrystallization process comprises the first step of cooling a saturated solution from a dissolution process having a temperature of 60 to 90 DEG C to a temperature of 35 to 50 DEG C at a cooling rate of T DEG C/hr, and the second step of cooling the solution from the first step to a temperature of 10 to 20 DEG C at a cooling rate of [T-18] T DEG C/hr to [T-1] T DEG C/hr. The method can be used for providing high purity potassium fluorotantalate crystals or high purity potassium fluoroniobate crystals having a good crystal particle diameter distribution which is suitable for producing tantalum or niobium particles for a high capacity capacitor without the use of a physical method for adjusting the particle size thereof.