| 摘要 |
<p>An improved hydrometallurgical method (10) for the extraction of nickel f rom laterite ores, the method comprising the method steps of: i) Forming at least one primary heap (20) from nickel laterite ore material; ii) Leaching the primary heap (20) with a leaching agent (22) to produce an intermediate leach solution (ILS) (24); iii) Recirculating the ILS (24) to the or each pr imary heap (20) whereby the concentration of nickel in solution approaches s aturation, or a steady state to form a pregnant leach solution (PLS) (26); i v) Passing at least a portion of the PLS (26) to an iron precipitation step (28) in which iron is precipitated as hematite at elevated temperature and p ressure, releasing acid; v) Directing the discharge from the iron precipitat ion step (32) to a solid liquid separation stage (34) to produce a waste res idue (40) and a clarified PLS (36) containing acid; vi) Irrigating at least one secondary heap (42) of nickel laterite ore material with the clarified P LS (36) to facilitate the leaching of the or each secondary heap and produce a secondary ILS (46); vii) Passing a stream of a reducing gas (50) into the secondary ILS (46) to facilitate the reduction of ferric iron to ferrous ir on; viii) Recirculating the ILS (46) over the or each secondary heap (42) to produce a secondary PLS (48); and ix) Directing the PLS (48) from step viii ) to a metals recovery circuit.</p> |
