Patent ID: 6338832
Filing Date: 2002-01-15
Classification: C01G,C01P,F02B,F02M,H01G

Abstract:
A process for producing a valve metal oxide precursor comprising:mixing in a first vessel an aqueous mixture of an ammonia solution and a valve metal fluoride compound at pH of about 6, at a temperature of from 30Â° C. to 95Â° C. for a residence time of from 0.03 hours to 2.0 hours to initiate precipitation of a hydrated valve metal oxide, wherein said valve metal is tantalum or niobium; transferring said aqueous mixture into at least a second vessel for mixing at the same or different temperature and residence time conditions as the first vessel and a pH of between 8 and 9.5 to continue further precipitation of hydrated valve metal oxide; and separating and recovering the hydrated valve metal oxide.