| 摘要 |
<p>Process for the treatment of rare-earth ores and, more particularly, ores with low contents of rare-earth elements. …<??>The process of the invention, which permits the recovery of the said rare earths, is characterised in that it consists:… - in performing the leaching of the rare-earth ore with the aid of a nitric acid solution,… - in separating off the insoluble residues if need be,… - in separating the rare earths from the solution originating from the leaching stage,… - in treating the solution purified with regard to rare earths with a hydroxide of a metal cation M and then separating off the said precipitate,… - in treating the solution which has been freed from the impurities with sulfuric acid and in then separating off the said precipitate,… - optionally, in recycling the nitric acid thus regenerated to the stage of digestion of the rare-earth ore. …<IMAGE>… </p> |
