Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  ..  22    24
Author: Subject: The trouble with neodymium...
SantinoCase
Harmless
*




Posts: 1
Registered: 7-9-2019
Member Is Offline


[*] posted on 7-9-2019 at 04:26


Quote: Originally posted by blogfast25  
Due to beaker breakage the investigation into the presence of Pr had to be abandoned (evidence lost!). Shame.

Below is another pic of the suspected mix of FeCl3 and PrCl3, with prominent green patches between 10 and 11 o'clock:

praseodymiummaybe.jpg - 37kB



Nd(OH)3.n H2O suspension about to be filtered, nice lavender colour:

s1600.jpg - 29kB



Nd(OH)3.n H2O on the filter:

s1600.jpg - 29kB



NdCl3.6 H2O (photo distorts colour), after dissolving Nd(OH)3 in HCl, crystallizing, washing with acetone and drying. Predictably perhaps, when viewed under a 'saver bulb' it takes on a decidedly greenish hue!

NdCl3.jpg - 21kB

Hi Same thing here, I think I need some stronger beakers.
Did you give it another try?
View user's profile Visit user's homepage View All Posts By User
BauArf56
Hazard to Self
**




Posts: 68
Registered: 22-8-2019
Location: between the moon and the sun
Member Is Offline

Mood: energetic

[*] posted on 13-3-2020 at 12:15


I tried the extraction with another method. I place some crushed magnet (with nickel cover) in a copper sulfate solution. After some hour solution turn green. In this solution should be ferric sulfate, nickel sulfate and neodymium sulfate. I add some potassium exacyanoferrate and turned dark red (nickel exacyanoferrate, i think). I filtered and the liquid should contain Nd2(SO4)3. Added sodium hydroxide and solution turn light blue. Is it neodymium hydroxide?
View user's profile View All Posts By User
Lion850
National Hazard
****




Posts: 483
Registered: 7-10-2019
Location: Australia
Member Is Offline

Mood: Great

[*] posted on 13-3-2020 at 22:32


Possible way to separate the dissolved sulfates: Neodymium sulfate solubility in water drops off greatly as the water get need 100 C. This causes the neodymium sulfate to precipitate out near boiling point and it can then be filtered out by filtering the near boiling solution.
View user's profile View All Posts By User
Bezaleel
National Hazard
****




Posts: 435
Registered: 28-2-2009
Member Is Offline

Mood: transitional

[*] posted on 16-3-2021 at 12:01


One of the problems with heating the solution to precipitate the RE sulfates is co-precipitation of other cations. Adding oxalic acid has traditionally been a successful method which largely avoids this.
View user's profile View All Posts By User
elementcollector1
International Hazard
*****




Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline

Mood: Molten

[*] posted on 13-10-2021 at 13:47


Decided to revisit this after... however many years it's been. Now that I have a job with access to a TGA (and various other scientific equipment), I wondered what the minimum possible temperature to go about the oxalate route was.

Turns out it's a lot lower than I expected - you can achieve satisfactory results at just 200 C. That's kitchen oven temperatures!

Full writeup is here- I wrote it like a paper because it's technically a sequel to my long-ago college term paper on neodymium recycling.




Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
View user's profile View All Posts By User
elementcollector1
International Hazard
*****




Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline

Mood: Molten

[*] posted on 7-11-2021 at 10:13


Checked some more literature and found my conclusions are wrong - neodymium oxalate's stable carbonate intermediary is the decomposition reaction between 400 and 800 C, not the one between 150 and 300 C - that one is actually the last water of hydration leaving the oxalate and any ferric oxalate present decomposing to ferrous oxalate. This explains why I continue to find iron present in the mixture after this reaction step and the triferrioxalate step - evidently there was still some undissolved ferric or unreacted ferrous oxalate still present. I used significantly more than the stoichiometric amount of oxalic acid (as well as lots and lots of water) to get the triferrioxalate to dissolve, but this wasn't enough? Either that, or the hydrogen peroxide and sulfuric acid added to the earlier 'magnet sulfate' solution didn't go all the way to ferric sulfate.

However, this does open up a new and much easier pathway to iron/neodymium separation, even if it doesn't fit within my original concept of only using kitchen oven temperatures - ferrous oxalate decomposes completely between 300 and 400 C, so heating the mixture to 400 for a few hours and then washing with sulfuric acid should remove the last traces of iron to leave a pure neodymium oxalate, which can then be decomposed easily at higher temperatures.

Referenced paper DOI's are here if anyone wants to read them:
10.1002/zaac.19633240110
10.1007/bf01113573




Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
View user's profile View All Posts By User
Bezaleel
National Hazard
****




Posts: 435
Registered: 28-2-2009
Member Is Offline

Mood: transitional

[*] posted on 16-11-2021 at 05:05


Very interesting, elemntcollector1!

Separating Nd from magnets is one of the first experiments I did when I started to do experiments again after I stopped doing so as a teenager. My conclusion back then was that the Nd in the magnets was impure because not all Pr had been removed from the Nd before the magnets were made. In a search I found that in order to get a strong magnet, not all Pr needs to be removed.

Do I understand you correctly that you found that the brown colour of the assumed Nd2O3 after calcination is due to the presence of iron compounds?
View user's profile View All Posts By User
elementcollector1
International Hazard
*****




Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline

Mood: Molten

[*] posted on 27-12-2021 at 19:34


Quote: Originally posted by Bezaleel  

Do I understand you correctly that you found that the brown colour of the assumed Nd2O3 after calcination is due to the presence of iron compounds?


That's correct. I also noted that increased temperature resulted in a more red-brown color typical of Fe2O3, while holding at 400 resulted in a more 'yellow' color (either partial Fe2O3 or 'yellow iron oxide' FeO(OH).H2O - unlikely to be the latter at 400 C, since all water of hydration should be long gone).

No data yet on mass loss between 400 and 800 C calcinations, but an easy way to check this assumption would be to run a longer 400 C decomposition to see if the color eventually matches the 800 C run.




Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
View user's profile View All Posts By User
Colleen Ortiz
Harmless
*




Posts: 19
Registered: 16-12-2021
Member Is Offline


[*] posted on 11-4-2022 at 01:54


The chemical element neodymium has the symbol Nd and the atomic number 60. It is the fourth element in the lanthanide series and is typically regarded as a rare-earth metal. It is a silvery, hard, relatively malleable metal that tarnishes swiftly in air and moisture. In the +2, +3, and +4 oxidation states, neodymium reacts swiftly to form pink, purple/blue, and yellow compounds. It is often considered as having one of the most complicated elemental spectra. Carl Auer von Welsbach, an Austrian scientist who initially found praseodymium, discovered neodymium in 1885. It may be found in substantial amounts in the ore minerals monazite and bastnäsite. Neodymium is seldom discovered in its pure metallic state or unmixed with other lanthanides, and it is frequently purified for widespread usage. Neodymium is a reasonably common element, roughly as abundant as cobalt, nickel, or copper, and is extensively dispersed in the Earth's crust. As with several other rare-earth metals, China mines the majority of the world's commercial neodymium. Neodymium compounds were first used commercially as glass dyes in 1927, and they are still a common glass addition today. The hue of neodymium compounds is attributable to the Nd3+ ion and is commonly reddish-purple, although it varies depending on the kind of illumination owing to the interaction of neodymium's acute light absorption bands with ambient light supplemented with mercury's sharp visible emission bands. Some neodymium-doped glasses are utilised in infrared lasers with wavelengths ranging from 1047 to 1062 nanometers. These have been employed in extremely high-power applications, such as inertial confinement fusion studies. In the Nd:YAG laser, neodymium is combined with a variety of different substrate crystals, including yttrium aluminium garnet. Another notable application for neodymium is as a component in alloys used to create high-strength neodymium magnets, which are extremely powerful permanent magnets. These magnets are commonly found in items such as microphones, professional loudspeakers, in-ear headphones, high performance hobby DC electric motors, and computer hard drives, where minimal magnet mass (or volume) or strong magnetic fields are required. Larger neodymium magnets are utilised in high-power-to-weight electric motors and generators (for example, in hybrid autos) (for example aircraft).
View user's profile View All Posts By User
 Pages:  1  ..  22    24

  Go To Top