Sciencemadness Discussion Board

Preparation of Neodymium Compound

ticoz - 10-5-2012 at 23:51

Currently I've tried to synthesize neodymium compound(NdCl3, Nd(NO3)3 and Nd(ClO4)3) from Nd2O3(99.9%).
These compounds will be dissolved in nonaqueous solution to conduct a electrodeposition.

I can make Nd(ClO4)3 easily. I just got a purple-colored Nd(ClO4)3 using only Nd2O3 and perchloric acid under air.
The XRD peaks of the powder I made were exactly same with Nd(ClO4)3 in JCPDS.
It was also dissolved well in nonaqueous solution(about 300g/L).

But, I met trouble with synthesizing NdCl3 and Nd(NO3)3, and dissolving them in nonaqueous solution.

The process that I used for making each compound are as below:
[Preparation of NdCl3]
I attempted to dissolve a mixture of Nd2O3 9g and NH4Cl 27g into 35.5ml of 35% HCl with heating about 70℃ under air.
To dry it and get crystal, the temperature slowly raised to 350℃ with fully dissolved solution.
What I made was a mauve colored solid under sunlight and the light-blue under fluorescent light.

[Preparation of Nd(NO3)3]
1. Nd2O3 9g + NH4NO3 38.5g + HNO3(60%) 30.5ml
2. Nd2O3 9g + HNO3 30.5ml
These are synthesized under air and dried at 350℃, so I got a light-purple colored solid.

The result of XRD of NdCl3 and Nd(NO3)3 I made was partially same with each data in JCPDS.
And NdCl3 was dissolved well in nonaqueous solvent(about 200g/L), but Nd(NO3)3 wasn't dissolved in nonaqueous solvent.


I wanna know how to synthesize NdCl3 and Nd(NO3)3 from Nd2O3 in detail.
Is anyone there who tell me some ideas about it and what is wrong in the process of mine?

[Edited on 11-5-2012 by ticoz]

barley81 - 11-5-2012 at 12:29

From Brauer in the Sciencemadness library. These are the preps for anhydrous rare earth salts.


Attachment: rare_earth_nitrates.pdf (200kB)
This file has been downloaded 493 times

Attachment: rare_earth_chlorides.pdf (298kB)
This file has been downloaded 680 times


elementcollector1 - 11-5-2012 at 20:01

A few questions, out of scientific curiosity.
-What is your nonaqueous solution?
-How do you plan to conduct the electrodeposition?

I just failed at making cerium through magnesiothermic reduction, so this is of great interest to me.

blogfast25 - 12-5-2012 at 05:46

Quote: Originally posted by elementcollector1  


I just failed at making cerium through magnesiothermic reduction, so this is of great interest to me.


What exactly did you do?

weiming1998 - 12-5-2012 at 05:55

Quote: Originally posted by elementcollector1  
A few questions, out of scientific curiosity.
-What is your nonaqueous solution?
-How do you plan to conduct the electrodeposition?

I just failed at making cerium through magnesiothermic reduction, so this is of great interest to me.


Cerium readily burns with even a small amount of air, even more so than magnesium, and very rapidly, so the vessel that you use has to be purged with argon, be air tight and heated to high temperatures. If oxides don't work, use a cerium halide to reduce with magnesium.

[Edited on 12-5-2012 by weiming1998]

blogfast25 - 12-5-2012 at 06:14

Quote: Originally posted by weiming1998  
If oxides don't work, use a cerium halide to reduce with magnesium.

[Edited on 12-5-2012 by weiming1998]



Unfortunately, what you write is highly simplistic.

Mg may just about reduce Ce oxide but MgO has such an insanely high MP (nearly 2,900 C!) that you will never obtain slag/metal separation but rather a sintered mess from which the cerium metal would be irrecoverable.

Reduction of an RE fluoride with Mg has been shown impossible (on this forum) because the ΔG for the reaction is close to 0. You would at best obtain a Ce/Mg alloy.

Reductions of RE chlorides with Mg are likely to suffer from the same problem. Possibly the only way would be to heat a mixture of the anhydrous RE chloride with Mg to higher than 1,000 C and under high vacuum. The MgCl2 is fairly volatile, even more so under vacuum, and would distil off, pushing the equilibrium towards Ce metal + MgCl2. Not for the faint of heart!


[Edited on 12-5-2012 by blogfast25]

barley81 - 12-5-2012 at 14:59

Cerium metal can be prepared by reduction of the chloride with calcium metal, by electrolysis of a mixture of the chloride with NaCl/KCl, or by electrolysis of an alcoholic solution of the chloride with a mercury cathode (followed by distillation to remove the mercury).

Attachment from Brauer (yet again)

Attachment: Metallic lanthanides.doc (467kB)
This file has been downloaded 434 times

elementcollector1 - 12-5-2012 at 18:14

I don't think mercury is within my means, but alcoholic electrolysis sounds viable. Is there any other cathode I can use (titanium, copper, aluminum, iron)?
How soluble are the RE chlorides in isopropyl?
Furthermore, how does isopropyl react to electricity?

ticoz - 14-5-2012 at 01:17

Quote: Originally posted by elementcollector1  
A few questions, out of scientific curiosity.
-What is your nonaqueous solution?
-How do you plan to conduct the electrodeposition?


I will use DMSO as nonaqueous solution, in which Nd compounds are dissolved well.
I will dissolve Nd compound into DMSO with supporting electrolyte, and then conduct electrodeposition using tri-electrode cell at room temperature.
I expect Nd metal to be electrodeposited on cathode.

I think at my experiment electrodeposition process is so simple: it will be conducted in DMSO with some supproting electrolyte at room temperature, that's all. But, I have only difficulty in synthesizing neodymium compound(NdCl3 and Nd(NO3)3).
So, I want some advice about making Nd compound.

elementcollector1 - 15-5-2012 at 20:09

I would refer you to this: http://www.youtube.com/watch?v=0hLEGMufP78
If MEK and isopropyl don't work, I would suggest the oxalate method (oxalic acid can be found as wood bleach). It separates iron and such from the neodymium efficiently and effectively.

Where do you get DMSO? (Sorry for all the questions, but I've never even heard of electrodeposition of rare-earths before.)

blogfast25 - 16-5-2012 at 05:14

The neodymium chloride this guy (thechemlife) obtained is likely to be heavily contaminated. To extract all ferrous chloride from a mix of Nd and Fe chlorides (with Fe being the majority component, neomagnets only contain about 25 w% Nd) by means of solvent extraction you’d have to grind the mixture very finely and subject it to multiple extractions or use a Soxhlet extractor. Just rinsing is unlikely to get rid of all iron. Ideally you’d dissolve a sample of the finished product in water and test for iron with thiocyanate or hexacyanoferrate.

He also mentions ‘boric acid’ but boric acid doesn’t come into it: neomagnets contain small amounts of boron but it isn’t converted to boric acid. Some of it escapes as boranes (which lends to the fumes a meaty, unpleasant smell), most of it just doesn’t do anything at all and should be filtered off, post-dissolution.


[Edited on 16-5-2012 by blogfast25]

Zan Divine - 16-5-2012 at 07:04

Anybody who produces reasonably pure, consolidated rare earths at home has my eternal respect (to go along with their sizeable lab equipment bill). Compared to the rare earths, all of group 1, P and many others are almost trivial.

I was interested in this for a brief time and then concluded that it's a waste of time. Why try to painfully reinvent the wheel? Group 1, P and similar are worthwhile targets since they can be hard to afford what with Hazmat fees, etc. P is difficult for other reasons. But they can be done without too much expense and a good chance of sucess.

You can buy any of the rare earths (even thulium, europium, etc.) much more cheaply than you can make them. And, unless you are a supremely talented individual with a fortune invested in equipment, your product will not even be close to commercial products in purity.

Realistically speaking, with the exception of a mere handful of elements, everything to the right of main group II and to the left of subgroups I and II are not going to be produced in good purity in your basement.

[Edited on 16-5-2012 by Zan Divine]

blogfast25 - 16-5-2012 at 07:51

Zan:

There is such a thing as 'the thrill of the chase', you know? ;)

kmno4 - 16-5-2012 at 08:30

NdCl3 and Nd(NO3)3 hydrates can be dehydrated to (practically) anhydrous salts, by high vacuum heating (stepwise, up to 180 C or so). Procedures can be found in some articles from Elsevier (use sciencedirect seareching engine).
Nd(NO3)3 hydratres can be converted to CH3OH solvates by simple heating with excess of CH3OH and distilling off water+methanol (frome some article in "Inorganic Chemistry" journal)

unionised - 16-5-2012 at 09:58

I predict electrochemical reduction of DMSO to dimethyl sulphide.