Sciencemadness Discussion Board

Purifying nickel salts from Inconel 625

497 - 5-4-2008 at 17:33

I have a fairly large quantity of said Inconel. I need to do some nickel electroplating and I'm going to use it as a source of nickel sulfate. It has a large quantity of other metals in it, mostly manganese, chromium, iron and a little niobium/tantalum (which I would like to recover if possible :)). Here's a good page on it

http://www.hightempmetals.com/techdata/hitempInconel625data....

I don't know any good ways to separate them off the top of my head, and Google hasn't resulted in much, except adding permanganate might precipitate the iron as oxide.

Also if anyone has a known working nickel plating bath, or even knows of one that might work with OTC chems, I would love to hear it. There's no way I'm getting hypophosphites or borohydrides so electroless plating is not much of an option. I have had some pretty good success with copper plating, so I have at least a little experience with this. Thanks.

garage chemist - 5-4-2008 at 18:12

Why do you want to destroy such a valuable alloy to get a simple element?
You need to order basic nickel carbonate from a pottery supplier. Or buy some nickel from ebay.

Is the nickel plating work for some anode use? The inconel might do as well as nickel in that case, you could try this out.

evil_lurker - 5-4-2008 at 18:24

I got 5lbs of nickel sulfate hexahydrate from www.seattlepotterysupply.com for $17

I'm sure a few pounds of unaltered inconel scrap sold to the right individual would easily pay for that.

[Edited on 5-4-2008 by evil_lurker]

not_important - 5-4-2008 at 19:01

I'll agree with the others - the cost of separating out everything is likely to run you close to the cost of buying nickel compounds. If the Inconel is in stock form it most certainly is going to be useful to someone.


Just for a feel, off the top of my head, Mo/Nb/Ta will precipitate out as hydrated oxides in weak acid, the last two will precipitate when CO2 is bubbled through their alkaline solutions.

Oxidate of iron to Fe(III) and precipitating as the hydroxide or hydrated oxide is an easy way to remove it, HNO3, H2O2, or Cl2 will oxidise it.

I think that adding alkaline NaOCl to a solution of Ni & Cr will precipitate the nickel as a mixed oxide and leave the chromium in solution as a chromate - could be wrong on this.

To get the alloy into solution may take HNO3 + HF, then adding CaCl2 + Ca(OH)2 to precipitate CaF2 + M0+Nb+Ta.

497 - 5-4-2008 at 20:25

Sighhh... yes I realize it is a valuable alloy, but I have about 10 kg of it in welding rod form. And I was only looking to make a little bit of nickel salt, I didn't really want to order a bunch and I don't want to wait a week for it to get here either. But I see now it will be a pain in the ass to purify and so I will try something else.

You are right about it being hard to dissolve. I was just playing around and I think I managed to begin to dissolve it although not very fast. H2SO4 + H2O2 had no effect. When some ammonium nitrate and hydrochloric acid were added it did certainly react, although the solution was decomposing too. Eventually it settles down to slow bubbling of what looks to be chlorine. I haven't let it go long enough to see how well it works, maybe its just catalytic decomposition. I know its not scientific, but I don't have time to do multiple controlled experiments.
And no I'm not making an anode, although I might in the future. At the moment I just want to see how well I can plate nickel.

Anyway, I just found some other welding rod (for cast iron) that seems to be a high nickel alloy with iron mostly. I think I'll try that, it should be a bit easier. Thank you not_important for the useful information.

No I don't really want to sell it... but if someone offered enough... ;)

[Edited on 5-4-2008 by 497]

Fleaker - 5-4-2008 at 20:28

If it was in tube form, I would've traded you 5 times its weight in nickel metal!! Inconel is useful stuff!

I think garage chemist gave the best option--the pottery supplier.

You may also try your local metals finishing shop--they will often use nickel for making a strike before electroplating some other (chrome) metal on afterward. I got several pounds of nickel for $7 several years ago from a large nickel and chroming company. Curiously enough, they were located on ''Nickel Plate Road" :)

497 - 5-4-2008 at 22:26

Oh yes I would definitely not be wasting it if it was tubing! :) But alas... its just wire of a measly 1/8" diameter or so... If anyone can think of an application for it I would love to put it to good use. I briefly though about casting it but that would be a bitch at over 1200*C. Plus I don't really have a specific use for it right now.

My needs for nickel plating at the moment are building a nickel/iron battery and as a preplating before gold on a ring. I'm not exactly sure which of the many varieties of nickel plating would be best suited for these, but ease and OTCness is most important. If anyone has plated nickel before speak up, specific information is scarce in my experiences of searching the web. I've found a few patents on it but they mostly require exotic brighteners.


[Edited on 5-4-2008 by 497]

not_important - 5-4-2008 at 23:25

You might be able to do your nickel extraction by electroplating, from a rod of Inconel onto some aluminium foil. You might be able to get this to work with an electrolyte of NaCl and HCl, the acid for taking up the chromium and iron while the valve metals fall to the bottom as hydrated oxides. This is guesswork on my part, but it might be fun to dink with.

You'll likely not get a good quality plating with this, but the goal is simply getting fairly pure nickel for further processing. The chlorine at the anode may be enough to overcome the passivation, or you may need a small amount of fluoride.

Treating the plated cathode with NaOH will dissolve away the aluminium, leaving the nickel. That can be dissolved in acid for a salt, or used as an anode when plating.

After that it gets tougher, good smooth nickel plating takes a bit of work. This especially true for the underlayer for gold plating. I believe you will need brighteners for that application.

497 - 6-4-2008 at 01:35

I was wondering about electrolytically purifying it, that sounds like a good idea. I'll have to try that tomorrow.

Ugh... brighteners... every patent states a different one is best. And theres A LOT of patents on nickel plating. Boric acid seems to be a decent one, and easy to make. Tarn-X works quite well with copper, maybe it would help with nickel too. Unless you happen to have some N-(benzenesulfonyl)-para-toluylamide or some quinolinium-N-propane-w-sulfonic acid laying around?

12AX7 - 6-4-2008 at 19:19

Quote:
Originally posted by 497
Oh yes I would definitely not be wasting it if it was tubing! :) But alas... its just wire of a measly 1/8" diameter or so... If anyone can think of an application for it I would love to put it to good use. I briefly though about casting it but that would be a bitch at over 1200*C.


Yup, but they use induction furnaces for that.

Interesting... ;)

Tim

497 - 7-4-2008 at 15:42

I'd looove to have an induction furnace. I love how clean and effective they are. The problem is I don't have to much experience with electronics, which seems to be a must have for a decent induction furnace. Someday maybe...

Contrabasso - 12-4-2008 at 23:48

Nickel plate is from a titanium mesh anode basket full of nickel lumps through an acid solution of the chloride and the sulphate to the cathode. Surface preparation is all, for plate adhesion.