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blogfast25
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Yes, but it's always preferred to start from something more homogeneous. An Ar blanket would also help here, to prevent Ca from reacting with air.
So, in short: NdF3 (possibly REF3?) + Ca pellets or shavings + external heating + argon blanket = worth trying.
[Edited on 31-8-2012 by blogfast25]
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elementcollector1
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Well, time to get some argon, then.
An argon blanket doesn't have to be refilled, right? It just sits there?
EDIT: Neodymium fluoride is insoluble, correct?
[Edited on 31-8-2012 by elementcollector1]
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blogfast25
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No, no: an argon blanket needs to be maintained with a constant flow. But a smallish flow should suffice.
NdF3 is water insoluble, thus quite easy to make. For synth. see a few pages upwards.
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elementcollector1
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So, setup would be something like this:
-A crucible with the reactant material of NdF3 and Ca metal is placed inside a steel can with a coal fire burning in it. A tube (steel? Ceramic?)
directs the flow of argon into the reactant crucible, and the argon is removed by (I don't know. It can't reach the coal bucket, otherwise the coal
will stop burning).
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blogfast25
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In your set up the Ar would extinguish the coal fire, because Ar is denser than air. The heat source would have to be OUTSIDE of the steel container.
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Lambda-Eyde
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Wouldn't it be possible to use a flux, like calcium chloride?
This just in: 95,5 % of the world population lives outside the USA
Please drop by our IRC channel: #sciencemadness @ irc.efnet.org
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elementcollector1
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So, how would I lead the argon away from the coal? A vacuum?
Also, the CaCl2 flux is probably a good idea, because no reactions can take place between it and the components, and it melts at 772 C or less (772 C
being for anhydrate).
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blogfast25
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Heat crucible inside a steel box with heat source acting on the box. Argon is the lead into the box, keeping it relatively air free.
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Poppy
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I heard no calcium would suffice to withsand the reducting powder of my gadjet! POWDER OF MY GADJET some1 whos already by means wasted a little effort
on putting that to words. Ok.
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elementcollector1
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Er...what?
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Poppy
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On what grounds you conceive calcium would reduce most other chemicals?
[Edited on 9-4-2012 by Poppy]
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blogfast25
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Quote: Originally posted by Poppy  | On what grounds you conceive calcium would reduce most other chemicals?
[Edited on 9-4-2012 by Poppy] |
Specifically in the case of NdF3, see here:
http://www.sciencemadness.org/talk/viewthread.php?tid=14145&...
But no one is claiming that "calcium would reduce most other chemicals". It's case-specific.
[Edited on 4-9-2012 by blogfast25]
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Gibberator
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Alright, so I have had an interesting development with my most recent attempt. I dissolved the magnets in Sulfuric acid and filtered, you know how it
goes. Anyways, after I precipitated the Neodymium as NdSO4*NaSO4. Then I treated it with a fairly strong solution of NaOH, upon which the precipitate
turned into the classic light blue of Neodymium Hydroxide. Unfortunately I couldn't get around to filtering it right away, partly to busy, partly just
laziness (heh), but when I finally got around to filtering I noticed that the precipitate had begun reverting its colour back to the same as the
double salt. I just assumed it had formed some more of the double salt so I added some more NaOH, except the colour remained the same. No matter how
many times I wash with NaOH, the precipitate remains the same. I'm not sure if what I have is Neodymium Hydroxide that doesn't resemble any Neodymium
hydroxide I have ever seen, or some weirdly nonreactive Double salt. Any insight to what this might be?
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blogfast25
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I have no idea and would simply start again, this time filtering immediately.
Try also dissolving what you're got now in strong HCl: appearances, especially with neodmium, can be deceptive. If it dissolves it's at least part
hydroxide.
The sulphate of neodymium is a strange compound, there seem at least to exist two forms of it, see also the neodymium thread by 'woelen' for nice
details and write up.
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elementcollector1
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So, I have that run of partially decomposed oxalate sitting pretty in a beaker of HCl. Do I need to add H2O2, or will this stuff dissolve on its own?
Also, how do I get rid of the newly formed oxalic acid?
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blogfast25
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I'm not sure it will dissolve. If it does, add NaoH to precipitate as Nd(OH)3.
If it doesn't, try conc. H2SO4, that should convert it to Nd sulphate. Decant off excess acid and wash a few times with hot water.
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elementcollector1
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The supernatant solution turned as black as if it had a fresh Nd magnet in there, but there is still plenty of precipitate.
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blogfast25
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Black???
Decant (or filter) it off and set aside (but don't throw).
Try attacking the rest with conc. sulphuric acid. It should then turn pinkish/red.
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elementcollector1
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Apparently the black color is due to the extremely dark purple color of the Nd (III) ion in this case, when a flashlight is shined upon the solution
it shows purple. Akin to permanganate, maybe.
The acid hasn't finished attacking the magnet, and now the magnet itself is covered in gray sludge (presumably undissolved metal).
If I add NaOH to this purple solution, I should get pale lavender Nd(OH)3, correct?
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blogfast25
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Check the colour of the 'black' stuff under incandescent light and TL light: it should look quite different under these sources if it is neodymium
chloride.
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Wizzard
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How's everybody's Neodymium isolation going?
A brief update of my own - I gathered all of my now well-dried small crystals, close to 30g of them (although I did not weigh it), and decided to
purify and recrystallize them into as large of crystals as I can.
On adding them to 300mL of 1*C pure water ("Infant" grade: steam purified, deionized, no additives etc), and waiting nearly 3 days for it all to
dissolve, my first stem I knew was I had to clean out the present iron sulfate impurity...
I first tried temperature swing, which had worked so well for me in the past... But there's so little of it, it was not effective at all. Humbug.
So I thought I would let the partially saturated liquid heat and slowly evaporate, leaving a more saturated liquid for me to try to chill to drop out
the iron sulfate.
After 2 days of this (I chose a very slow evaporation), liquid being held at approx. 55*C, I was reminded of my early difficulty growing Iron Sulfate
crystals from powder... Without the addition of sulphuric acid to lower the pH, it reacts with the air to form insoluble (and not particularly
flocculent) iron hydroxide! It sinks and sticks to the bottom of the vessel (for the most part) and my solution will be easily decanted and filtered.
The neodymium compounds remains in solution, but I will be testing the filtrate for neodymium content.
I'll be posting pictures of the crystals as soon as the batch is done... However, I'll be growing them rather slowly.
I can take a picture of the vessel as it is now - Lovely lavender on top, pukey yellow-brown on bottom. And I will add, the lavender color of the
Nd(III) is enhanced with purity.
[Edited on 6-17-2013 by Wizzard]
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blogfast25
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Hey Wizzard!
Pictures would always be appreciated.
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Wizzard
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Here's one  The cluster of 2 crystals is more than 2" across, and still growing.
Today, the junk crystals started growing... I think I need slower growth. But evaporation is certainly my method of choice.
http://imgur.com/FBn637q
Also, of note - ANY agitation causes nucleation and sporatic crystal growth. Do not rotate the vessel for pictures  That happened the other day - The mess of small crystals are the result.
[Edited on 6-24-2013 by Wizzard]
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Poppy
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For the growth of large neodimmy crystal, I can't believe you guys have gone this far thats an absurd, do you just heat it up or carefully control the
temperatures the whole time?
I developed a method for growing large ferric ammonium sulfate crystal by adding elemental aluminium, slowly, into a saturated solution of the later,
bringing strange shift in the equilibrium which ultimately cause slow temperature-constant precipitation onto a single crystal. That might work with
neodymium, as changing the temperature might cause different lattices to overlap over the crystal as it grows, leading to imperfections.
Too bad my mon throwed the heavy load of dimmy's magnets I had so imma kind not inclined to use my 20g of material in this task as purification proves
a real pain when dealing with Al contamiantions!!
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Wizzard
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Actually, it's all in the preparation. I work out of a storage room, I don't even really have a countertop. My "hot plate" is a 17W candle heater. I
have a vent immediately behind my work surface, and I keep the area as dust and cat hair free as humanly possible.
Using the absolutely cleanest recycled labware, I recrystallize and purify the magnet soup, removing most of the iron sulfate in a few cycles, the boron within 2. From this, I
crystallize the mixture, disposing of the remaining dissolved Nd and Fe sulfates once I cannot stop the Iron Sulfate from crystallizing at high
temperature.
From the resulting solids, I manually extract the Nd sulfate crystals. They were small, but easily picked up and collected.
From this, I dissolved them over the course of 3 days in alternating freezing/cold steam-purified water, after a quick hot rinse to remove any clingy
Iron sulfate. I used only lab-grade Coffee filters, but I am meticulous about keeping EVERYTHING clean. No fingerprints, breathing, etc.
Once the crystals are all dissolved, the mixture is filtered again, into it's final container. This container is topped with a 1-ply paper towel, to
keep ANYTHING out, but slowly let the hot water vapor out.
The container is put on the hot plate, which will heat the liquid to around 60*C. I insulate the container with a sheet of insulation, to keep the
condensing liquid on the walls to a minimum. The dripping can be problematic.
Over the course of nearly a week, the crystals will grow. Without agitation, and with as few controlled nucleation sites as humanly possible, you will
get very large, single crystals on the bottom of your container.
Mine grew for a few days, with only 2 crystals, before I attempted to rotate the container to snap a pic... This action is not recommended, I soon had
a city of crystals, but at least it was not a blanket 
As of today, I am re-dissolving the crystals into a splash more water, to try single crystal growth again. Wish me luck!
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