| 摘要 |
<p>Ammoniacal liquors (1), in which nickel, copper and other metals are dissolved, are subjected to countercurrent extraction in at least two stages (2, 3) with the aid of an organic solution (4) in order to remove the copper at least virtually completely, together with some of the nickel. A washing appliance (7) is used to separate ammonia from the laden organic solution by means of dilute sulphuric acid. A three-stage extraction appliance (10, 11, 12) is employed to extract nickel from the solution by means of a sulphuric acid stream (13) in countercurrent thereto. The resulting, weakly acidic nickel sulphate solution (14) is heated, and nickel sulphate is crystallised in a vacuum evaporation crystalliser (16). From the copper-laden organic solution copper is removed in a countercurrent extraction appliance (19, 20) by means of a sulphuric-acid solution, and metallic copper is produced from this aqueous phase in an electrolytic system (22). From the electrolytic system (22), most of the sulphuric acid solution is returned to the extraction appliance (20, 19), and a small portion is used in the washing appliance (7) for removing the ammonia from the laden organic solution. The organic solution (4) free of copper and nickel is returned into the liquor extraction appliance (3, 2), so that the organic solution in a closed circuit flows through all the extraction appliances (3, 2; 7; 10-12; 19, 20). The process provides for economical production of metallic nickel owing to the simultaneous extraction of copper and part of the nickel directly from the ammoniacal liquor at the site of the ore processing plant. The otherwise required, laborious selective removal of the copper prior to producing the nickel is no longer required, as the nickel carbonate conveyed to the refinery is free of copper. A further improvement is achieved, in addition to the production of metallic copper, by producing pure crystalline nickel sulphate for nickel electroplating. <IMAGE></p> |
