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Author: Subject: Quest for the elements
blogfast25
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[*] posted on 10-2-2016 at 07:03


Quote: Originally posted by crystal grower  
Maybe its a stupid idea but would it be possible to make elemental boron by putting Al rod into molten Boron trioxide ?? (It doesnt matter how pure it will be).


None of the problems mentioned in the thermite thread would be solved by that.




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[*] posted on 10-2-2016 at 13:17


Added another element sample: red phosphorus.

I have taken appr. 4 grams of red phosphorus and added all of it to 80 ml of water. To this water, I added 1 ml of bleach and stirred the whole mix for a while. You get an opaque red liquid and when stirring is stopped, quickly a dark red/brown slurrie settles at the bottom, while the liquid above it remains a lighter red. Next, I decanted the liquid and left the mud at the bottom. This process removes all very fine particles and the bleach assures that any traces of white phosphorus which may be present in the red P are destroyed as well.

Next, I put the dark red/brown mud on a piece of filter paper and pressed it dry as good as possible between the folded filter paper, around which a thick layer of paper tissue is wrapped. Nearly all water is absorbed by the paper tissue. The result is a fairly dry coarse powder of phosphorus. I transferred this nearly dry powder from the folded filter paper to a petri dish and put this in an oven at 100 C for 15 minutes. After these 15 minutes I stirred the dry powder with a spatula, broke apart some larger clumps of powder and made a really free flowing powder of this. This powder was put in the oven for another 15 minutes at 100 C. After that, I took it out of the oven and transferred it to an ampoule, while still warm, using a small glass funnel. Next, I immediately sealed the ampoule. Inside the ampoule I have a perfectly dry dark red/brown powder, which hardly sticks to the glass, so that the sample can be viewed nicely.

All this preprocessing of the red P is done in order to make it really dry and to remove all the fine particles and to remove traces of white P. Without this treatment, you get a sample, which is somewhat sticky and the inside of the ampoule then quickly is covered with a red smear, which blocks the view on the sample and makes it look ugly.

I am quite happy with my ampouled sample of red P. Making good-looking samples of elements is less trivial than I thought a few months ago. Humidity, very fine dust, and stickiness of materials is your greatest enemy. They make samples look ugly. Unfortunately nearly all cheaper samples of elements suffer from at least one of these things. For instance, I purchased a 20 grams sample of arsenic in a nice ampoule. Unfortunately, the arsenic is covered in a thin greyish/white layer of oxide and this sticks to the inside of the glass ampoule and this dust makes the sample much less attractive. It looks foggy and irregular.





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[*] posted on 10-2-2016 at 14:40


This is sounding great woelen. I bet those element collections look gorgeous.
Are you preparing them to sell or just for your own pleasure or what?


I intend to follow your procedure to clean up my arsenic before ampouling. Red and white P are further down the list.




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[*] posted on 11-2-2016 at 00:00


I make these samples for my own pleasure. I want to display them in a big periodic table display (appr. 1.5 meters wide, appr. 7 cm width of available space per element).

If you want to prepare the arsenic according to my procedure, then I would suggest doing a final rinse with a very weakly acidic solution of K2Cr2O7 and allow that to act upon the arsenic for a few minutes and then rinse the arsenic very well with cold water (can be tap water). This last treatment with K2Cr2O7 makes the arsenic less prone to oxidation. I do not know why this is, but my observation is that arsenic, which is treated with dichromate and in which not all dichromate is used up before rinsing, is much more stable on storage. It remains shiny and grey instead of black.

[Edited on 11-2-16 by woelen]




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[*] posted on 11-2-2016 at 00:14


Thanks for that woelen. I confess that I have not remembered all the details of your arsenic preparation. I intend to look them up thoroughly as well as this little addendum before I attempt it. I also need to develop a waste disposal plan. That (and limited time in the lab) are the two things keeping me back at the moment.

I am tempted to ampoule an oxidised sample of As as well. I think it will make a good before/after picture.
My element display (when completed) will be less of a display and more of a hands on thing with each element telling a bit of a story with accompanying card. So, for lead, its most significant property is its density and availability. I want a 15kg ingot to show that. But for thallium I want a tiny ampouled sample -- this much can kill you.



[edit]
So that the bits are together in one place...
woelen's arsenic cleaning methodology
http://www.sciencemadness.org/talk/viewthread.php?tid=63777&...
http://www.sciencemadness.org/talk/viewthread.php?tid=63794&...

Other info
http://woelen.homescience.net/science/chem/elem/elements/As/...
http://www.sciencemadness.org/talk/files.php?pid=421072&...


[Edited on 11-2-2016 by j_sum1]




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[*] posted on 11-2-2016 at 23:50


I now can make ampoules from test tubes as well. In this way, I ampouled 99.99% Al-pieces which are too large for a real ampoule and I also ampouled 20 grams of beautiful oxide-free and shiny Co-pellets, 99.99%. These test tube ampoules look very nice, the only thing is that they have a fairly long thin "tail", which I cannot snap off without the risk of creating a crack near the seal.

More elements are on the way and I will ampoule them myself:
- rhodium (ordered thin chips, 0.1 gram in total, but due to their large surface area they show the metal quite well)
- silicon (ordered chunks of appr. 0.7 cm size for just a few euros)
- chromium (electrolytic grade, 99.95%)
- iodine (ordered 99.95% 1 ounce for just EUR 6 or so)
- bismuth (ordered a chunk of 50 grams 99.9% metal, which I will shatter with a hammer and then ampoule the pieces)

In this way I can make element samples for low prices. Many metals and most solid non-metals can be ampouled perfectly and having a small amount of air in the ampoule is not a problem for them. The elements for which I really need to buy ampoules (if I want nice durable oxide-free displays) are the lanthanides, alkali metals and earth alkali metals. These elements cannot be ampouled without special equipment if you want a nice oxide-free sample.




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[*] posted on 12-2-2016 at 06:43


Something I've noticed with bismuth is that it too oxidizes in air over time. Freshly exposed surfaces are bright and silvery, but after several days in air they gain a yellow tings. They never lose their shine, but that's definite evidence of a thin oxide layer (which is well-known in bismuth crystals, of course). So I'd recommend storing the bismuth under argon, even though it's not one you would expect would need it!
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[*] posted on 14-2-2016 at 08:03


Here you can download some pictures of ampoules I made in the last few days:

http://woelen.homescience.net/ampoules/

I had samples of elements in little vials, or in plastic baggies and now I put all of these in nice ampoules. I have made more, this is a fairly random selection of appr. half of the ampoules I have made.

--------------------------------------------------------------------------------------

I also purchased a few ampoules: H, D, He, N, O, Ne, Ar, Kr, Xe all of them at low pressure so they can be excited easily by means of a high voltage high frequency oscillator (my ZVS driver project will come back to use again).

I purchased ampouled samples of Fe, Mn, Sm. These metals tarnish or rust in air and can only be kept free of oxide layer when ampouled under argon or vacuum. That kind of ampouling is beyond what I can do at home, so these samples I had to buy.




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[*] posted on 16-2-2016 at 11:32


Looks great! What was your procedure to ampoule liquid chlorine? I was always afraid it would crack the glass from heat stress (cold Cl liquid, hot melted closure) or develop dangerous internal pressure after warming up.

Edit: Or perhaps that's one of your halogen solutions. I should wait a bit before I type.

[Edited on 2-16-2016 by MrHomeScientist]
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[*] posted on 16-2-2016 at 12:20


The chlorine indeed is one of my halogen solutions. It is 100 ... 150 ml of chlorine gas, dissolved in 5 ml or so of CCl4. I made these solutions, because they very nicely demonstrate the color of the halogens.



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[*] posted on 16-2-2016 at 12:43


They do indeed! I assume your picture of all the halogen solutions is chlorine, bromine, iodine, but what is the fourth brown solution?

I have a small amount of carbon tetrachloride and it would be neat to see this in action myself!
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[*] posted on 17-2-2016 at 00:04


The fourth brown solution also is iodine, but this time in diethylether.

Solutions of iodine can have a very characteristic purple color, or a very characteristic brown color. The purple color is in alkanes and chlorinated alkanes. The brown color is in alcohols, ethers, esters and quite a few aromatic compounds. Because both colors are very characteristic for solutions of iodine, I decided to make both. I chose ether, because a solution of iodine in that is stable indefinitely.




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[*] posted on 21-2-2016 at 03:39


Has anyone of you tried extracting even very little amount of Indium from PC scrap ?
If yes could you write me instructions please?
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[*] posted on 21-2-2016 at 14:08


there is Indium in LED monitors, but it will be miniscule amounts. collect the gold instead and sell it for indium :)



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[*] posted on 21-2-2016 at 14:28


Elements collectors,
A nice source of elements are hollow cathode lamps, used in the Atomic Spectrometry technique.
When exhausted, you can get them from labs or even e-bay.
Most of them use the pure element; some few others use some salt. Lamps are under low pressure of a noble gas.
Ask a glassblower to open them or develop the skills: take out the socket, scratch the seal with some widia or carbide tool and touch the mark with a hot glass rod in order to propagate a crack. After that you can open the envelope with the classic procedures -a hammer, a red hot wire surrounding the perimeter, a new scratch with carbide tool, a dremmel cutting disk-
The element is contained in a small cylinder at the center of the lamp, some few grams. Precious metals just in form of a thin foil or an electrolytic deposit.
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[*] posted on 25-2-2016 at 07:42


Is there any readily available source of manganese metal?
I dont want to make thermite as it is very messy and the yield is mixed with Al2O3 and could also easily oxidise.




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[*] posted on 25-2-2016 at 07:53


Quote: Originally posted by crystal grower  
Is there any readily available source of manganese metal?
I dont want to make thermite as it is very messy and the yield is mixed with Al2O3 and could also easily oxidise.


An OTC source? Not as far as I know. The metal itself doesn't have a lot of applications. You can of course buy it from some sources.

A well-designed MnO2 will yield about 30 % metal. Nice little chunks with a minimum of luck. Most of it doesn't oxidise at all.




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[*] posted on 25-2-2016 at 13:49


Yep, I've done MnO<sub>2</sub> thermites several times, and have recovered little nodules of metal each time. They are brownish in appearance, but you can tell they are the metal by their spherical shape (more or less). If you carefully crack one of these in half, you can expose the shiny metal surface underneath. It isn't the prettiest sample, but I'm happy with it because I made it!

That same process applies to most thermite varieties. Manganese of course has low yield because most of it boils off.
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[*] posted on 25-2-2016 at 23:53


Nice samples of manganese are hard to obtain. The metal is very easily oxidized and becomes covered by a brown layer of mixed oxide (Mn2O3, Mn3O4, maybe even some MnO2).

If you want an element sample of manganese and you want it to stay good, then the metal must be ampouled under argon. You could even ampoule it in plain air, then it only oxidizes slightly, until all oxygen in the ampoule is used up. Manganese, stored in every other type of vessel eventually will become covered with a dark oxide layer. I have some electrolytically produced manganese, stored in a bottle with a screw cap, but this manganese looks ugly.

Two weeks ago, I purchased a sample of electrolytically produced manganese from smart-elements.com, 5 grams under argon:

http://www.smart-elements.com/?arg=detail&element=Mn&...

Quite expensive, but the sample really is beautiful! It shows the true color of manganese metal without a trace of oxide. It has a silvery appearance with a faint golden tinge. All the nodules on the pieces are shiny as well. I really wonder how they could produce such nice electrolytic samples.

Some elements really must be purchased if you want them in a nice shiny way, unless you have a very well equipped lab, capable of handling materials in an inert atmosphere and ampouling while under an inert atmosphere.




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[*] posted on 26-2-2016 at 01:21


Quote: Originally posted by woelen  
Manganese, stored in every other type of vessel eventually will become covered with a dark oxide layer. I have some electrolytically produced manganese, stored in a bottle with a screw cap, but this manganese looks ugly.


I have 4 ounces of electrolytically produced manganese in large flakes form, and 30 gm of pieces, all in screw cap bottles and it all looks dark. Is there a way to clean some of the pieces to restore the appearance. I don't have Argon but I have hundreds of ampoules in large and small (5ml, 2ml) that I was thinking of using to store nice specimens of some of my elements. If a simple way to clean the metal exists what about storing the sample in a vacuum, which is easy to do for me. Also have a few 13 gm pieces under oil of DU that I could take a slice from to fit in an ampoule if there is a safe easy way to remove the dark oxide layer.




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[*] posted on 26-2-2016 at 01:55


Here's a random idea...

You could attempt to make a Mn mirror on the inside of an ampoule using hydrazine.

Au and Ag mirrors are common. Cu can be done with hydrazine. ISTR tin being done also. Manganese would be quite cool. Closing the ampoule would protect it from oxidation.

(blogfast25 will likely be here shortly to tell me that it is thermodynamically inviable with Mn. But it is an idea.)




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[*] posted on 26-2-2016 at 01:57


Is anywhere a list of oxides that could be reduced only using heat in hydrogen atmosphere?



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[*] posted on 26-2-2016 at 02:52


Durable Mn-mirrors cannot be made. Mn is very reactive, and I expect it to react (very slowly) even with water.

I ampouled many elements in test tubes. These allow larger samples to be ampouled and with a hot blow torch it is fairly easy to make a seal. I take my test tube and put the sample in. Next, I heat it halfway, keeping the round bottom part with one hand and the open side with the other hand. I keep the round bottom side somewhat lower to avoid the sample moving outwards. The flame is halfway. The glass at a certain time starts melting. If this occurs, I slowly move both ends from each other. I do not rotate or bend, just move the halves apart. The middle part becomes more and more narrow. When it has a width of 6 mm or so, I stop moving and allow the middle part to become orange/yellow hot. You can easily see when it is completely sealed (at that part you do not see a darker air-channel through the narrow part). When the seal is complete, I slowly move both parts further away from each other, assuring that the half with the sample remains in the flame. The result is an ampoule like this:

silicon.jpg - 264kB

First practice with empty test tubes, or test tubes with material in them which is not valuable. When you have done this with 3 or 4 tubes, you have the right feeling and then you can do this with a nearly 100% succes rate. Just be sure that your flame is sufficiently hot. You can do this with your bare hands, the ends of both halves do not get hot, they just become warm.

I also cleaned quite some elements, before I ampouled them. E.g. I had severely oxidized vanadium. I put this in 5% HCl for just a few seconds and then rinsed with distilled water and dried the pieces with filter paper and then in an oven at 80 C for half an hour before ampouling them.

@IrC: You could try doing this with Mn-pieces, but use very dilute acid. Mn reacts violently with acids and if the acid is too concentrated you quickly dissolve your sample. Try with 2% HCl and keep the sample in for a while and watch its color change.
Quickly rinse them in a large amount of water (under running tap) and then dry with a towel or filter paper. Next, allow to dry further, e.g. for half an hour in an oven at around 100 C. Do not ampoule too soon, otherwise you will get condensed water on the inside of the ampoule, which looks ugly.
I do not think that with Mn you will get a nice sample, completely free of oxide layer, but the sample definitely will look much better than what you have now. Personally I first would try the cleaning process with a small part of your Mn. The cleaning with acid does not work OK for all elements. I also tried with Co (electrolytic flakes with black oxide). I could make the pieces totally free of oxide, but they became a dull white/grey. The surface of the flakes is etched and becomes matte. This also might happen with manganese, I don't know.

The following elements can be treated with 5% HCl without the surface being etched:
- arsenic
- vanadium
- titanium
- niobium (requires a _tiny_ amount of NaF or HF added to dilute HCl)
- tantalum (also requires a tiny amount of NaF or HF)

In my experience, chromium and cobalt are etched and the surface becomes dull and matte.

Silver can be treated with 3% HNO3 and becomes very nice and shiny again. Silver can also be put in a solution of Na2CO3 and brought in contact with Al-foil.

Results with copper are not satisfying. It tarnishes again when it is dried. The nice soft rose/orange color of very pure and smooth copper becomes harder, more orange/red when the metal dries.




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[*] posted on 26-2-2016 at 02:58


I have used a (brass or steel) wire wheel brush for polishing samples without ruining the look also. if you can do it in argon even REEs will stay pretty good.



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[*] posted on 26-2-2016 at 05:31


Have anyone tried separation of cobalt from AlNiCo magnets?
If yes could you tell me at least briefly the procedure you have used?
Thanks a lot.




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