SEPARATION OF NICKEL SULFATE AND METALLIC NICKEL BY USE OF NICKEL IODINE AQUEOUS SOLUTION

摘要

PURPOSE:An excessive amount of metallic nickel powder is added to a mixture of hydroiodic acid and sulfuric acid to generate hydrogen and consume the whole amount of these acids, whereby NiI2, NiSO4 and powdered metallic nickel are readily separated utilizing the difference in their densities. CONSTITUTION:A nickel powder is fed through pipe A to the hydrogen-generating reactor 1, hydroiodic acid and sulfuric acid through pipe B and the hydrogen gas evolved is released from pipe C. Then, the mixture consisting of an aqueous solution mainly containing NiI2, hydrated NiSO4 and of powdered nickel is sent to the first solid-liquid separator 2 where the nickel powder is separated by sedimentation and returned to the reactor 1 with the slurry pump 5. The residue is fed to the second solid-liquid separator 3 and the slurry containing the hydrated NiSO4 is sent to the third solid-liquid separator 4 with the pump 6. Crystals of hydrated NiSO4 free from liquid is separated in the separator 4 and taken out through pipe D. The aqueous solution containing NiI2 is partially taken from the separators 3 and 4 through pipe E by an appropriate amount and the rest is returned back to the reactor 1 with the pump 7.