| 摘要 |
<p>Iron is recovered from an iron containing dust obtained in processing iron or steel by dissolving iron and bivalent metals being present in said dust in an acid. Subsequently the iron is precipitated by adding an alkaline substance or ammonia to adjust the pH to 5 to 8. Before or during precipitating the iron the bivalent ions as present such as zinc, cadmium and lead are converted into a soluble complex by means of a complexing agent. Preferred complexing agents are polyamines, particularly triethylene tetramine being an excellent complexing agent for zinc. The precipitated iron hydroxide is recovered and may be reused. The process may be separated more than once in the same solution, thereby providing a final solution containing considerable amounts of zinc, cadmium, or other bivalent metals which may be separated by boiling or precipitation. The complexing agent may be recovered by destillation after having made the complexes strongly alkaline or by precipitation by adjusting the pH to 1 and recovering the salt of the complexing agent such as a hydrochloric acid salt of the complexing agent.</p> |
