Preparation of super-high purity niobium oxide by adjusting valence state extraction and ceramic membrane filtration combined with antimony removal

Extraction separation is a major method for making high purity niobium oxide. Under certain conditions, it can achieve the aim for making high purity niobium oxide. But as the raw material of impurities are complicating, especially difficult to separate impurity Sb, it is difficult to rely on extraction for making high purity niobium oxide. Thus, new methods to solve the problem of excessive Sb should be invented. In this paper, adjustment valence extraction and ceramic membrane filtration were combined to reduce Sb content to the greatest extent by adjusting valence extraction, and the principle that Nb and Sb have different solubility under certain conditions is utilized. Nb and Sb can be filtered and separated to the greatest extent by dissolving special dissolving reagent and removing Sb by ceramic membrane filtration, thus achieving the purpose of preparing ultra-high purity niobium oxide (ω(Sb) < 5×10^-6, 5 ppm).