Improvement in a process to separate cobalt values from nickel values in an aqueous solution of nickel sulphate containing cobalt

摘要

"IMPROVEMENT IN A PROCESS TO SEPARATE COBALT VALUES FROM NICKEL VALUES IN AN Aqueous SOLUTION OF NICKEL SULPHATE CONTAINING COBALT". An improved process for separating cobalt values from nickel values in an aqueous solution containing nickel and cobalt sulfate, in which the solution is contacted with a water immiscible organic solution containing an organophosphoric acid in a cobalt extraction circuit. the process is particularly useful for aqueous solutions containing high content of total metals and high concentrations of cobalt, while preventing the formation and precipitation of double salts containing ammonium sulphate during the extraction of solvent from cobalt. the improvement includes contacting a portion or all of the water-immiscible organic solution needed to extract cobalt with an ammoniacal solution containing nickel to produce a nickel-laden organic phase and a partially depleted nickel raffinate. The nickel-charged organic phase is then passed to the cobalt extraction circuit for selective cobalt extraction, where the nickel is displaced from the organic phase by cobalt to produce a nickel-rich, depleted cobalt raffinate and a cobalt-charged organic phase . Advantageously, the nickel-containing ammoniacal solution is generated by adjusting the nickel-containing raffinate of the cobalt extraction circuit, through the addition of ammonia, preferably in the form of ammonium hydroxide, and ammonium sulfate.