| 摘要 |
<p>Arsenic and sulphur are removed from ores as arsenate or sulphate by treating the ore with aqueous alkali metal hydroxide whilst aerating with air or oxygen. The primary metal values are separable as elements or oxides. The reaction is preferably effected at 100-200 DEG C. at a pressure of 50-200 p.s.i. Excess alkali metal hydroxide is preferred and the digest slurry is preferably filtered hot, at 75 DEG C. Sodium arsenate may be separated from the undissolved residue and recovered by cooling to 32 DEG C. The sodium arsenate may be treated with lime to form calcium arsenate and caustic soda which is recycled. An example refers to the treatment of an ore containing, in addition to arsenic and sulphur, substantial proportions of iron, cobalt and nickel.</p> |
