Sciencemadness Discussion Board

Good sources of cerium

CobaltChloride - 27-5-2018 at 12:20

I've recently began studying the lanthanides more closely and I learned that Ce (IV) is a very strong oxidizer with very interesting properties which can replace KMnO4 (which is completely banned in Romania; it is treated the same as red P or iodine are treated in the US) in many situations. What would be a good source of this metal/its compounds? CeO2 is sold dirt-cheap as a cleaning powder, but I'm afraid that might be calcined so much that it doesn't react with anything. Another possible source are the ferrocerium rods, which contain iron, cerium and smaller amounts of other lanthanides, but, as far as I'm aware, extracting cerium from them would require first dissolving them in dilute nitric acid (or sulfuric acid if you have access to M(NO3)2 where M has an insoluble sulfate; I don't), then oxidizing Ce(NO3)3 to Ce(NO3)4 with hydrogen peroxide and then extracting this salt with light naphtha (or any other non-polar solvent; I chose light naphtha because it is very cheap here), but this method wastes valuable nitric acid.

TL;DR: What cheap source of cerium do you recommend? Is cleaning CeO2 good? Is there an OTC method of extracting cerium from ferrocerium rods? (dilute H2SO4 is the cheapest acid here, light naphtha is the cheapest non-polar solvent)

j_sum1 - 27-5-2018 at 13:20


CobaltChloride - 27-5-2018 at 13:30

I know the site, but the price for cerium salts is huge (at that price I'm better off doing the extraction from ferrocerium)! Also, I've heard the CeO2 they have (which is more reasonably priced) is unreactive.

[Edited on 27-5-2018 by CobaltChloride]

diddi - 27-5-2018 at 13:52

what about lapidary grade cerium oxide?

CobaltChloride - 27-5-2018 at 14:02

That is what I was referring to when I was talking about "cleaning CeO2". My question is: is the material reactive towards aqueous acids or is it so calcined that it becomes unreactive?

Dr.Bob - 27-5-2018 at 18:19

Ceric Ammonium Nitrate is used in many labs, that would be my first thing to try to find a sample of if I wanted a pure cerium compound. It is often used for visualizing TLC plates and other oxidations.

DavidJR - 27-5-2018 at 19:27

Quote: Originally posted by Dr.Bob  
Ceric Ammonium Nitrate is used in many labs, that would be my first thing to try to find a sample of if I wanted a pure cerium compound. It is often used for visualizing TLC plates and other oxidations.

I would quite like to buy some but I haven't found anywhere that will sell it to me.

Bert - 27-5-2018 at 20:08

Ceric Ammonium Nitrate on Amazon

Or from Chemsavers?

ninhydric1 - 27-5-2018 at 20:17

Maybe you could try electrolysis with a ferrocerium rod in, say, sulfuric acid. Wikipedia states that cerium readily dissolves in dilute sulfuric acid, so I don't think that nitric acid is needed. Iron can be readily dissolved by HCl, so that shouldn't be a problem.

CobaltChloride - 27-5-2018 at 22:22

I chose nitric acid because only Ce(NO3)4 has the property of being soluble in nonpolar solvents. Ce(SO4)2 isn't soluble in nonpolar solvents. If anyone has a better method of separation, I'm all ears.

CobaltChloride - 27-5-2018 at 22:26

Quote: Originally posted by Bert  
Ceric Ammonium Nitrate on Amazon

Or from Chemsavers?

Again, these are a lot more expensive than just extracting from ferrocerium rods or buying ceric ammonium nitrate from onyxmet.

indigofuzzy - 3-6-2018 at 17:03

Ferrocerium rods will dissolve readily in HCl.
If you get the stoichiometry right, only the cerium and other stray lanthanoids will dissolve, and the iron will be displaced out of solution as a black powder.

fusso - 4-6-2018 at 12:51

Plz recommend brands of cleaning powder that contain decent amount of CeO2. Ive never heard of this fact.

elementcollector1 - 4-6-2018 at 13:28

Ferrocerium actually contains a significant bit of La (something like 50% Ce, 25% La, balance Fe/Mg if I recall, though that's a very uncontrolled recipe so it can vary quite a bit).

'Cleaning cerium' doesn't refer to any cleaning product, but rather a polishing slurry used for stones and other hard lapidary substances. From my experience, it isn't terribly reactive, but you can force it by reacting with magnesium or another reducing agent, dissolving the resultant mixture of magnesium and cerium compounds in an acid of your choice, and separating the magnesium.

What's more fascinating still is that certain brands of pool phosphate remover are, apparently, pure lanthanum chloride in aqueous solution. I've boiled these down and got a clean white precipitate with little trouble (though I haven't verified its contents just yet).

CobaltChloride - 5-6-2018 at 07:46

What kind of pool phosphate remover has LaCl3? Why would you use such an expensive (because of the cost of the separation from other lanthanides) chemical for a pool?!

@fusso search for "cerium oxide" on ebay or aliexpress and you'll get a lot of offers for CeO2.

Dancing Rain - 9-6-2018 at 04:39

What kind of pool phosphate remover has LaCl3?

It's called PhosPrevent, and is readily available from pool supply stores in Portland OR. Your mileage may vary elsewhere.
I'm going to try to extract lanthanum metal from it as soon as my budget permits.

wg48 - 9-6-2018 at 10:17

Nice find DR.

I am surprised too that lanthanum chloride is used for something as mundane as precipitating (presumably) the phosphate out of pool water.

I found an msds for a similar product called PhosFree. It states it contains 26.52% LaCl3

I also found PhosFree on sale at about £50 for 3 litres + about £50 delivery. About £10 for 80g of LaCl3.

LaCl3 is also sold on Ebay UK. The best price I could find was about £30 for 100g

Attachment: phosfree-extra-strength-msds.pdf (138kB)
This file has been downloaded 282 times

elementcollector1 - 11-6-2018 at 20:23

I can't quite recall the product name that I came across, but I do remember it was available at Walmart (~$8 for 16 fl. oz.) and claimed 60% lanthanum chloride in solution. Precipitation with sodium hydroxide yielded a gelatinous, white precipitate that dried to give a crumbly, brittle powder (La(OH)3, if I'm right). The white color indicates that it doesn't contain Nd, Ce, Pr, or other rare earth contaminants in any appreciable amount.

What is your plan for extraction, Dancing Rain? I seem to recall MrHomeScientist attempting neodymium from its oxide a while back, with... limited success. I was thinking electrolysis in propylene carbonate, but that would first require dehydration of the hydrated chloride (unfortunately difficult due to formation of useless oxychlorides).

[Edited on 6/12/2018 by elementcollector1]

violet sin - 11-6-2018 at 22:10

The HTH brand of pool supply chemicals has theirs listed as 35-65% lanthanum salt and 65-35% water. Clorox brand is 6-10%, so.... There seems to be some variation in composition. Yet another brand had no named substance as it wasn't considered toxic enough... That doesn't sound good. I've been tempted to buy before, but due diligence may be required as it's not the cheapest stuff.