Niobic Acid Aqueous Solution

Abstract

A niobic acid aqueous solution is provided having higher dispersibility than an ammonium niobate sol and having better solubility than a complex salt of niobic acid. The niobic acid aqueous solution contains 0.1 to 40 mass % of niobium in terms of Nb2O5, wherein no particles of 1.0 nm or more are detected in the particle size distribution measurement using dynamic light scattering. A method for producing the same includes adding a niobium fluoride aqueous solution containing 1 to 100 g/L of niobium in terms of Nb2O5 to an ammonia aqueous solution having an ammonia concentration of 20 to 30 mass % and reacting them, removing fluorine from the obtained reaction solution, and adding at least one selected from amines and ammonia to the obtained solution and reacting them.

Dependencies are inferred from the claim text.