Sciencemadness Discussion Board

Recovery of Cesium salts from Pollucite ore.

BromicAcid - 1-8-2004 at 19:00

Cesium salts are expensive and that is the limiting factor to my involvement with this alkali metal. But I found a simple method to extract relatively high purity cesium salt from its chief ore pollucite. If only I had a source for pollucite, might have to go rock hunting, but I digress.

Procedure from the series entitled "Inorganic Syntheses":
Quote:

Cesium Alum Method
Submitted By Robert West and Robert P. Anderson
Checked by Lewis I. Krimen and Therald Moeller

Pollucite is broken into pea sized lumps with a hammer and then ground in a ball mill until fine enough to pass though a 120-mesh sieve. One hundred grams of screened pollucite is mixed with 400 ml of 50% sulfuric acid (7.1 M) in a 1-L round-bottomed flask and refluxed gently for 30 hours. The mixture is diluted with 250 ml of water, heated to boiling, and filtered with suction, using a large, coarse, sintered-glass funnel. The silica residue is washed well with hot water.

The hot solution is cooled to 0C, and the well-defined octahedra of cesium alum are collected on a sintered-glass funnel and washed with cold water. A small second crop of crystals is obtained when the filtrate is concentrated to about 450 ml and cooled. The yield is about 110 g., or nearly 90% (for Varutarask pollucite).
Properties

Cesium alum crystallizes in colorless octahedra which melt at 117 C. This compound is more insoluble then the other alkali-metal alums and is remarkable for its high temperature coefficient of solubility. At 100C, 12 is soluble in 100 g of water; at 0C, only .19 g is soluble. Because of this property, the cesium compound is readily prepared in a high state of purity by recyrstalizing it from water.


An interesting and straight foreward procedure.

Magpie - 2-8-2004 at 15:37

I also like the idea of extracting metals from ores - it is just so fundamental.

If you don't want to invest in a ball mill you can buy an 8 oz capacity iron mortar & pestle for <$30 at http://www.minerox.com/ I have one and it did a nice job of pulverizing a 1/2" piece of gravel from my driveway.

[Edited on 2-8-2004 by Magpie]

Re: Caesium

JohnWW - 3-8-2004 at 02:39

Pollucite, the principal (silicate) ore of Cs mentioned, is itself of fairly rare occurrence.

How about looking at the possibility of extracting Cs from sea-water? I think that, like Li and Rb, it occurs in sea-water at about 1 ppm levels. Of course, as an alkali metal, its occurrence there is greatly surpassed by the Na and K. Like Li, it could conceivably be extracted, along with Rb, from sea-water with some sort of ion-exchange resin, from which, when packed in a column, the much larger fractions containing all the Na and K could be discarded.

Although the physiological action of Cs and Rb in plants is similar to that of K, which is essential to and concentrated by plants, there may be some plant species which selectively absorb Cs and Rb in preference to K.

John W.

unionised - 5-8-2004 at 13:28

If this table http://www.seafriends.org.nz/oceano/seawater.htm
is right, then the concentration is 0.0003 ppm. That means that for each gram of Cs you need about 3000 tons of seawater.
Have you got a big bucket?

Cs and Rb in seawater

JohnWW - 10-8-2004 at 14:19

3 grams of Cs in 3000 tonnes may not sound much, if you have read it correctly, but with sufficiently large and efficient pumps, and sufficiently efficient ion exchange resins (if they could be found) to separate Cs and Rb from the Na and K, it should be feasible. I have heard of plans to extract elements like Au and Th, found in even lesser concentration, from sea-water, and of ion-exchange separation already being used to obtain Li from sea-water.

John W.

Polverone - 10-8-2004 at 15:01

So are there any operations where you're already processing seawater on vast scales and could get additional minerals as an almost-freebie? The closest I know of is the extraction of bromine from seawater, but bromine is far more abundant than cesium. I've read of pilot-scale Japanese efforts to extract lithium, uranium, and vanadium from seawater, various schemes ranging from really-kooky to conceivable for gold from seawater, and proposals for other metals, but nothing that's reached full-scale production.

unionised - 14-8-2004 at 04:33

Lithium is about 7 times as expensive as cesium and about 500 times more common in sea water.
There is a real demand for lithium for industrial purposes and for the nuclear and pharmaceutical business. There is also a real demand for bromine, perhaps less so than when it was added to leaded petrol, but real.
The demand for cesium is a few chemists in research labs and a few physicists with clocks. If you were able to double the world's supply of cesium you would pretty much halve the price.

I don't think the ecconomics don't make sense.
Also, if I shift that 3000 tonnes of water I can hope to extract a gram of the stuff., worth about £0.82 which would buy me about 40 KWh of energy (based on my gas bill). I'm not sure that 40Kw would process 3000 tonnes in an hour, its only enough to lift the water about 15 feet clear of sealevel.

[Edited on 14-8-2004 by unionised]

Polverone - 14-8-2004 at 11:40

Lithium is more expensive than cesium?! Either you've found a great bargain-basement cesium compounds dealer or you're paying too much for lithium compounds!

For example, Aldrich wants $35.10 for 500 g of 99% lithium carbonate and $99.50 for 250 g of 99% cesium carbonate. The price differential is much smaller with highly-purified materials, presumably because the price of purification is large compared to the price of raw materials.

You can buy technical grade lithium carbonate (for pottery) for less than $16/kg. I've never found any cesium compound of any grade for sale near that price.

BromicAcid - 14-8-2004 at 17:31

One biochemistry web site sold cesium chloride for the unbelievable price of $175 a kilogram, that for me was pretty cheap.

BTW, I read recently that lithium is one of only two metals that has actually increased in price (when leveled with the consumers price index) over the last twenty or so years, probably due to the difficulty of processing ore and the highly increasing demand for it.

unionised - 17-8-2004 at 08:18

"Lithium is more expensive than cesium?! Either you've found a great bargain-basement cesium compounds dealer or you're paying too much for lithium compounds! "
Or I goofed, and got them the wrong way round.:(
The point is that cesium is rare and almost useless so it's expensive.
The concentration in the earth's crust is estimated as 27 ppm so you would do better picking up a random rock rather than the same weight of seawater. (though, I realise the rock would be harder to process).

halogen - 17-8-2004 at 08:57

Steps for mining oceanic materials::D
1. Create nuclear reactor and steadily improve it until tremendous power output.
2. Buy a few tons of freshly evaporated sea salt, seaweed, and such.
3. Perform a massive electrolysis!
4. Separate the halogens and similar materials and sift through the metal.
5. Sell the metallic parts or save some, and keep the tanks of precious fluorine, chlorine, bromine... and I dont really think you can put iodine in a tank...
6. Use money to uprade reactor and buy raw sea materials. (Repeat)
7. Repeat until you have all the metals and halogens and chemicals and money you need.
------------------------------------
Yes... I have gone mad...
:P

rift valley - 17-8-2004 at 09:46

Hmmm. Back in the late 1800's and early 1900's they were various pollucite ore mines in nearby Maine. In the last weeks of summer maybe I'll take a trip over there and see what I can find.

vulture - 17-8-2004 at 10:54

According to Römmp, seawater contains about 1 microgram of Cs per liter.

When Bunsen and Kirchhoff (sic) extracted it from Bad Dürkheimer (Germany, Eiffel) mineralwater they needed about 42000L to produce a few grams IIRC. And that water is supposed to be enriched with it because of vulcanic activity...

unionised - 17-8-2004 at 14:41

I don't supose it matters much if it's 1 gram in 1000 tonnes or 1 gram in 3000 tonnes.
A few grams in just 42 tonnes is a lot better, but I'm glad I didn't have to do that experiment.

lacrima97 - 10-2-2006 at 20:40

Does anyone know of any sources of pure cesium?

neutrino - 10-2-2006 at 20:57

This sounds like it should be in a new thread.

Are you looking for a cesium salt or the metal itself? If you're looking for the metal, look for chemical suppliers (very expensive), element suppliers (less expensive) and eBay.

lacrima97 - 10-2-2006 at 21:13

Yeah, I have noticed that the pure metal (what I want) is extremely expensive. I believe that electrolysis of a cesium compound is out of the question, so I am going to just rid myself of the idea. I have nor the money for the pure metal, nor the stupidity to electrolize such a metal.

By stupidity, I mean with my equipment.

woelen - 11-2-2006 at 05:15

And what kind of experiments did you have in mind for the elemental cesium? The stuff is so reactive (e.g. explodes in contact with water, inflames in air), how would you manage to keep it around without causing accidents?

neutrino - 11-2-2006 at 08:25

Store it under mineral oil?

Bromic's patent for making sodium in the 'unconventional sodium' thread also includes an easy synthesis for elemental Cs. Keep in mind though that no one here has gotten the processes in that patent to work yet. We're still trying to figure it out.

The_Davster - 11-2-2006 at 11:26

Cs is just so reactive I would likely not feel comforatble working with it at home without an inert gas atmosphere glovebox. Cesium hydroxide is so corrosive that if your cesium were to react with air or water accidently you would have a nasty spill on your hands.

If I get this summer research scholarship I applied for I will get to play with elemental cesium and other lower alkalis to make alkali mercurides and aurides.:cool::cool:

olmpiad - 6-2-2007 at 20:15

I did the procedure as first stated, but reduced everything to 10% of the original weights. It actually works quite well, and the Cs-Alum forms very quickly by placing the solution in a fridge (after about four hours of decanting). Ill post pictures soon. They crystals do not look too much different than normal alum, but their solubility is a dead give away. First Cs salt I've ever made, and it was quite a success! Ill post pictures soon.

[Edited on 2/7/07 by olmpiad]

unionised - 8-2-2007 at 03:11

Where did you get the ore from?

olmpiad - 10-2-2007 at 14:54

Picture:

Unionized:
i got the Pollucite from my mineral collection (minerals are my passion), It is from a rare locality in California.

pantone159 - 10-2-2007 at 16:00

One link offering to sell pollucite samples, $25...
It doesn't say how much, though.

http://www.sciencemall-usa.com/polcesmin.html

olmpiad - 13-2-2007 at 17:14

I find that quite expensive. The site says that the specimen comes in a Perky Box, which means that it is a TN specimen. As for size reference, this is known as a Thumbnail to us mineral collectors, which is exactly what it sounds like: the size of your thumbnail. In other words, probably no more than 5g, and it cost 25$. I paid $7 for my specimen, and it is a C (for those of you who do not collect minerals, this is known as a Cabinet size), and it weighs a good 500-600g.

re-use of cesium compounds

freachem - 30-3-2007 at 01:28

Hi, I used cesium carbonate in an organic reaction which included the use of halobenzenes etc. Do you perhaps know of an efficient method for the recovery and reconversion of the cesium halides back to the carbonate. As mentioned this stuff is really expensive so any recovery would probably be worth attempting.

not_important - 30-3-2007 at 02:00

Depends on what else is in your aqueous workup. Most common cesium salts are very soluble, except for the alum. Ion exchange resins are used to remove cesium from radioactive wastes, they might be a way to concentrate the cesium if there's other alkali metal ions around.

At this point all I can think of is to convert it to the alum, adding sodium and aluminium sulfate and concentrating to get the cesium alum to crystalise, collecting the cesium alum, and calcining it in a stream of CO2. You'll lose about a half gram of the alum per 100 ml of solution.

freachem - 30-3-2007 at 03:05

Thanks

Just for added info

The by products are cesium iodide, cesium bromide, and a triphenylphosphor copper complex. The reaction was carried out under nitrogen. The salts were filtered free from the solvent mix. Some water may have been produced during the reaction.

Thank you again for the info

[Edited on 30-3-2007 by freachem]

ThatchemistKid - 17-5-2011 at 18:22

I just bought 1 kg of CsCl for 21.50 I assume though that this then was an outrageous deal? I dont need that much I am willing to sell off 300 grams of it for like 70 dollars per 100 grams if anyone is interested?