| 摘要 |
<p>Phosphorus and titanium-containing solutions of hafnium and/or zirconium nitrate, are purified by (a) eliminating a major part of the phosphorus as phosphates of Hf and/or Zr, e.g. by decanting the precipitate which forms on settling; (b) diluting the solution to 1.5N; (c) passing the solution through a cation exchange resin, to fix the Hf and/or Zr and the traces of phosphate and Ti; (d) eluting with 1.5 nitric acid to eliminate Ti; (e) eluting Hf and/or Zr with 1.5-3N sulphuric acid; (f) allowing the resulting solution to stand, and decanting to eliminate last traces of phosphorus as phosphates. In step (a), the P2O5: Hf and/or Zr oxide ratio is preferably reduced to 0.2-0.3%. The cation exchange resin may be an aromatic hydrocarbon polymer containing sulphonic groups. In an example, the sulphuric elution solution was treated with gaseous ammonia to precipitate the oxides of Hf and Zr which were filtered, washed and calcined at 900 DEG C.</p> |
