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Published on: February 11, 2012
On the stabilization of niobium(V) solutions by zirconium(IV) and hafnium(IV)
1Risø National Laboratory, Roskilde, Denmark.
Abstract:
Niobium cannot be separated from zirconium or hafnium when these elements occur together in solution with common anions such as chloride and sulphate. This is ascribed to the co-polymerization of niobium(V) and the hydrolysed ionic species of zirconium(IV) and hafnium(IV) to form colloidal particles. In hydrochloric acid the particles are positively charged, whereas in sulphate solution the Zr-and Hf-sulphate complexes confer a negative charge. The two cases are considered separately.
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