| 摘要 |
<p>Ores or ore concentrates containing tantalum or niobium or both, as minerals of the pyrochlore-microlite series are leached with an alkali metal hydroxide solution to produce water-soluble phosphorus and sulphur compounds. 20 to 40% w/w alkali metal hydroxide solution may be used for leaching at 75-95 DEG C. for 2-8 hours. The ores may first be roasted with alkali metal hydroxide and water (from 5 to 10% by weight of ore) at 300-700 DEG C. for 1/2 to 1 hour. Examples relate to the leaching of a pyrochlore ore concentrate, with and without prior roasting, followed by washing with water, filtering, drying and igniting the residue. Values of the sulphur and phosphorus contents of the leach and leached ore are given.</p> |
