[Platinum]

I'm planning an assignment where I'm supposed to purify Ni. My start material is already dissolved Nickel, NiCl2 from HCl(aq) wich was yellow from the beginning (now it's too late). To get rid of the impurities in the HCl (aq) solution I'm thinking of reacting the NiCl2 with NaOH to get water insoluble Ni(OH)2, wich I'm washing with water several times and filter off. Then I was thinking to react Ni(OH)2 with very clean HCl (aq) and evaporate the resulting salt with addition of water several times until vapors are neutral. I think I don't get rid of some metals like Cu in this stage, but Fe, Zn and Pb should be separated out. 

Would recrystallization of NiCl2 with EtOH or iPOH help? I don't have solubility data for NiCl2; the only information I have is that NiCl2 is to some extent soluble in EtOH. Recrystallization with water before making the hydroxide? I had the thought that what forms hydroxide is another chloride and will probably also dissolve similar as Nickel Chloride; so my conclusion is that the hydroxide step does (more than) what the recrystallization step does.

I'm then planning to dissolve NiCl2 in water and add fine Al (~80 mesh) to start a double displacement, where Ni(II) gets reduced to Ni(0). Wouldn't this Nickel be significantly purer than without this procedure? Have I missed anything? I don't have a Master degree, and even those who have can most often not answer many of my questions. I can't find anything about purifying Ni without advanced equipment.

[Platinum]

Of course I must separate out Al with NaOH as the final step, and wash the Ni with water. I'm then thinking of melting the Ni to an ingot. 

[Arkcon]

You could start with how nickel is purified industrially.  You really should have, before you started adding reagents.  Also, you should try to find solubility data from a reference book.  That's likely an important part of this assignment.  FWIW, its not common (but then again, not rare either) for solvents to greatly affect the solubility of ionic compounds.  You might have noticed that with a bit of research into nickel and its common compounds.

[Platinum]

You could start with how nickel is purified industrially.  You really should have, before you started adding reagents.  Also, you should try to find solubility data from a reference book.  That's likely an important part of this assignment.  FWIW, its not common (but then again, not rare either) for solvents to greatly affect the solubility of ionic compounds.  You might have noticed that with a bit of research into nickel and its common compounds.

Solubility data I haven't find, so maybe I make my own. Industrial purification according to some methods I can find, where a solution of NiSO4 in which Fe was removed as Ferric Hydroxide after oxidation with H2O2 or Ammonium Persulfate. Further, Cobalt ions were removed by electrolytic deposition on a high speed rotating electrode. Cobalt was according to this source the most difficult to remove by conventional methods; obviously as a result of their very similar properties. Nickel was finally extracted with hydrogen gas under pressure at 180 C. Well, I can do all this except high speed rotating electrode. Ion exchange could according to this source also remove Co, I'm more thinking of if the metathesis maybe also giving this effect.

http://prr.hec.gov.pk/Chapters/2603H-6.pdf