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

Title:

Document Type and Number:

WIPO Patent Application WO/2002/083568

Kind Code:

A1

Abstract:

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 ° C to a temperature of 35 to 50 ° C at a cooling rate of T ° C/hr, and the second step of cooling the solution from the first step to a temperature of 10 to 20°C at a cooling rate of [T-18] T°C/hr to [T-1] T°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.

Inventors:

SOHAMA YOSHIO (JP)
ISAKA HIROMICHI (JP)
HIGASHI KENJI (JP)
KINOSHITA MASANORI (JP)

Application Number:

PCT/JP2002/003286

Publication Date:

October 24, 2002

Filing Date:

April 02, 2002

Export Citation:

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Assignee:

MITSUI MINING & SMELTING CO (JP)
SOHAMA YOSHIO (JP)
ISAKA HIROMICHI (JP)
HIGASHI KENJI (JP)
KINOSHITA MASANORI (JP)

International Classes:

B01D9/00; C01G33/00; C01G35/00; C01G35/02; (IPC1-7): C01G35/00

Foreign References:

US3907976A	1975-09-23
JPH0421524A	1992-01-24
JPH042618A	1992-01-07
JPS4932897A	1974-03-26
JPH01192728A	1989-08-02
JP2001329321A	2001-11-27

Other References: