Solvent extraction process for separating cobalt from nickel in aqueous solution

摘要

A process for separating Co from Ni in an aqueous solution comprises subjecting the solution to extraction and using kinetic differences between Ni and Co in the extraction for achieving at least a partial separation of Co from Ni. This is effected by controlling the duration of the extraction so that a major portion of Co and a minor portion of Ni is extracted from the solution to produce a loaded extractant, enriched in Co and depleted in Ni compared to the feed solution, and a Co-depleted raffinate containing Ni. In a further embodiment, the invention utilizes kinetic differences between Ni and Co during striping for effecting separation of Ni and Co. The loaded extractant can be subjected to a bulk stripping or a selective stripping operation to obtain Co and Ni solutions from which Ni and Co can be recovered. The process may be incorporated in a hydrometallurgical process for the extraction of Ni and/or Co from an ore or concentrate containing Ni and Co.

主权项

1. A process for separating and recovering Co from Ni in an aqueous feed solution, comprising:
subjecting the feed solution containing Ni and Co and impurities comprising Mg and Mn to extraction with an extractant and using kinetic differences between Ni and Co in the extraction by controlling duration of the extraction, thereby separating the Co from the Ni, and from the Mg and the Mn, whereby a major portion of Co and a minor portion of Ni is extracted from the feed solution to produce a loaded extractant and a Co-depleted raffinate containing Ni wherein the loaded extractant is enriched in Co and depleted in Ni compared to the feed solution, wherein the concentration of Ni in the feed solution is greater than the concentration of Co, and wherein the duration of extraction is about 30 to 240 seconds, wherein the feed solution contains impurities comprising at least one of Mg, Mn, and Ca wherein the molar ratio of (Mg+Mn):Co in the feed solution is at least 6:1, wherein the extraction is carried out in two successive stages, and wherein at least one of the two successive stages comprises adding an alkali to the extractant at about 0.01 to 0.15 grammole per liter of extractant.