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Upsilon
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Thanks for the information, I'll do some looking around. Also, I can see why you would think that I'm trying to tackle the difficult elements first,
but that's not what I'm doing here. Right now I am just in the thinking stage; I am planning out how to isolate each one. The easy ones I don't really
need clarification on. Essentially I am asking about these ahead of time; I am not necessarily trying to get them in the order I'm posting them.
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Little_Ghost_again
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Quote: Originally posted by aga  | Reading your link to the Be experiments in the penultimate post reminds me of why i first came here and stayed.
Science, Chemistry, Facts, Experiments, Results !
There are even chemical equations in there to accompany the photos.
Time to turn SM around and re-take that Fascinating high ground and get back to some actual interesting Science instead of all these random chat-room
style random Lizard Alien type comments that appear all the time.
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It wasnt long ago you were a newb, this is the newb section! People have to start somewhere like you did, if there is a lack of science going on then
maybe its time attitudes changed to those that are new and of little knowledge.
How many times have people complete debunked things in a high and mighty manner only to be proved wrong later on. I posted the picture because its
well known in recycling that you have to be careful of the magnetron and the Be bit on it.
The intention was merely to show a potential source and not provide in depth details of what it was or how to process it. Ok aga you do experiments
but before moaning about real science take a look in in pre pub, those are the people who actually do real science and there arnt many names in that
place.
If you dont have a section like beginners then you will never grow a community, 99% of people who post in this section wont get passed it, but the 1%
that do will end up doing real science.
The danger is discouraging people from posting crap, once you start doing that you are going to miss out on the 1%.
Also some of us do things that fail and dont like posting about it, I asked in a thread on the iodine about getting back some of the acid with vacuum
distillation, I thought a quick simple answer would give me a direction.
I didnt think it worth bothering searching for ages and as no one posted anything back I assumed it was ok.
Turned out far from ok.
So yes now I will research first but I am less likely to ask questions in the first place now.
Dont ask me, I only know enough to be dangerous
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Upsilon
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I'm going to try the phosphate reduction reaction for fun. However I think it would be reasonably difficult to determine the presence of H3PO3 in a
mixture of oxalic and phosphoric acid. Instead I think I'm going to construct an electrochemical cell; that way I will easily be able to tell if a
reaction is occurring by measuring the voltage of the cell (theoretically it will be 0.154 V). I don't have much knowledge beyond your basic,
easy-to-understand cells, but I'm going to take a shot in the dark here. One of the half-cells will be a 1M phosphoric acid solution, the other a 1M
oxalic acid solution. Graphite electrodes. A salt bridge would consist of an acid to allow migration of H+ ions. Am I on target here, or completely
off?
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woelen
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Phosphoric acid cannot easily be reduced. Thermodynamically it may seem feasible, but there is no easy mechanism (pathway) from phosphoric acid to
lower oxidation state compounds. Only very strong and very reactive reductors are capable of reducing phosphoric acid.
This property sometimes is used to an advantage as well. E.g. from phosphoric acid it is possible to make HBr from NaBr or HI from NaI or KI. With
sulphuric acid this is impossible, the iodide and also the bromide are oxidized and you get all kinds of unclean side reactions.
Thermodynamic data only is one part of the equation, a viable pathway for the reaction is the other part. You can compare this to a heavy ball laying
on the top of a hill, with the ball having a lot of potential energy, ready to be used to convert to kinetic energy if the ball moves down the hill
and gains speed. If the hill has a rounded top and has a smooth surface, then a small push of the ball suffices to set it in motion and then it goes
down with ever increasing speed. Now imagine that at the top of the hill (which still has the same height), the ball has a dike around it. The ball
still has the same potential energy, but now you have to put more effort in using that potential energy. You first have to push it over the dike. An
occasional push does not lead to the ball going down the hill. You first have to add some energy, before you are rewarded with much more kinetic
energy. Now you can compare phosphoric acid in aqueous solution to a ball, which is on a hill, but with very high walls around it. The walls may be
even higher than the height of the hill, so a LOT of effort must be put into the system before its energy can be released.
Conclusion: A cell, based on phosphoric acid will not work and oxalic acid will not reduce phosphoric acid. Oxalic acid simply does not push hard
enough to get the ball over the dike.
[Edited on 2-10-15 by woelen]
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Upsilon
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So I guess that leaves the question, where did they come up with those reduction potentials? Is it based on a prediction, or did they actually make it
work somehow?
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blogfast25
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| Quote: Originally posted by Upsilon | | So I guess that leaves the question, where did they come up with those reduction potentials? Is it based on a prediction, or did they actually make it
work somehow? |
Once you have a set of redox reactions that involve the H<sup>+</sup>/H<sub>2</sub> half-cell (+0 V, by convention) that
kinetically work, you can start combining hitherto unknown reductions (or oxidations, that is only a matter of sign!) with known ones in cells that
actually work. The reduction potential is always relative to the H<sup>+</sup>/H<sub>2</sub> half-cell.
Today we have large databases of the Gibbs Free Energies of Formation of aqueous species. Combining these allows, with Nernst's theory, to actually
calculate standard reduction/oxidation potentials for 'new' systems.
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Upsilon
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Makes sense. Looks like there's still no better route to phosphorus that doesn't involve high heat and/or toxic gases.
I would also like to note that I just received a golfball sized orpiment (arsenic trisulfide) in the mail today. However I'm not going to try anything
with it for a while yet. I'll post again when I'm ready to have a go at separating out the arsenic.
This weekend I'm going to try isolating titanium from titanium dioxide with the information in this thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=21332#...
[Edited on 3-10-2015 by Upsilon]
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blogfast25
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It'd be nice to see yet someone else prepare some rough Ti metal with my method. 
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elementcollector1
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| Quote: Originally posted by Upsilon | Makes sense. Looks like there's still no better route to phosphorus that doesn't involve high heat and/or toxic gases.
I would also like to note that I just received a golfball sized orpiment (arsenic trisulfide) in the mail today. However I'm not going to try anything
with it for a while yet. I'll post again when I'm ready to have a go at separating out the arsenic.
This weekend I'm going to try isolating titanium from titanium dioxide with the information in this thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=21332#...
[Edited on 3-10-2015 by Upsilon] |
Out of curiosity, where on Earth did you find such a lump of orpiment? Was it cheap?
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Upsilon
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Oh absolutely, they're all over eBay. Mine specifically is 91g, and it cost me $10 plus $3 for shipping.
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Upsilon
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Was busy today so I didn't get around to the titanium thermite. However I did start the process of making the calcium sulfate for the reaction. I
mixed solutions of calcium nitrate and sodium carbonate to precipitate calcium carbonate (I'll also be keeping the sodium nitrate). I'll then react
the calcium carbonate with HCl to make calcium chloride, which I'll then mix with ammonium sulfate to make calcium sulfate. Sure I could just mix the
calcium nitrate and ammonium sulfate to begin with but I don't really want to deal with ammonium nitrate right now.
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j_sum1
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Sounds convoluted, but should work. Make sure your CaSO4 is anhydrous before you attempt the thermite.
Do you have any CaF2 for a flux?
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Upsilon
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I do. However it is taking a long time to process all of this calcium carbonate; I probably won't get to the actual thermite today.
For the time being, I've been speculating about easy ways to create lithium metal. I discovered that lithium nitrate has an extremely low melting
temperature, and that it could easily be melted on a hotplate. Is electrolysis of this salt viable? The temperatures are so relatively low that it
could even be done under mineral oil. I have lithium carbonate on hand and it would be quite easy to make the nitrate out of it.
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blogfast25
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| Quote: Originally posted by Upsilon | I do. However it is taking a long time to process all of this calcium carbonate; I probably won't get to the actual thermite today.
For the time being, I've been speculating about easy ways to create lithium metal. I discovered that lithium nitrate has an extremely low melting
temperature, and that it could easily be melted on a hotplate. Is electrolysis of this salt viable? The temperatures are so relatively low that it
could even be done under mineral oil. I have lithium carbonate on hand and it would be quite easy to make the nitrate out of it.
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CaSO4? Just get the cheapest, no-frills wall filler (that's the hemi-hydate) and dehydrate it. That's what I used.
I see you're getting NaNO3 as a by-product? Well, that works very well as a heat booster for the TiO2 thermite too! Better even than CaSO4.
Electrolysis of LiNO3? I believe someone reported on that here. Mine was ridiculously deliquescent but maybe that was just that grade, not sure...
[Edited on 4-10-2015 by blogfast25]
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Upsilon
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| Quote: Originally posted by blogfast25 |
CaSO4? Just get the cheapest, no-frills wall filler (that's the hemi-hydate) and dehydrate it. That's what I used.
I see you're getting NaNO3 as a by-product? Well, that works very well as a heat booster for the TiO2 thermite too! Better even than CaSO4.
Electrolysis of LiNO3? I believe someone reported on that here. Mine was ridiculously deliquescent but maybe that was just that grade, not sure...
[Edited on 4-10-2015 by blogfast25] |
I may just use the sodium nitrate then, less steps until I'm ready to actually start. I also wanted to make some calcium chloride so I figured I might
as well go through with this process.
As for the lithium nitrate, I may do it this week sometime. I could make it by compining it with the calcium nitrate I have but lithium carbonate
isn't very soluble, so that may not be the best route. Otherwise I'll have to wait on my cheapie distillation glassware to come in from China so I can
get started making nitric acid.
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blogfast25
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| Quote: Originally posted by Upsilon |
I may just use the sodium nitrate then, less steps until I'm ready to actually start. I also wanted to make some calcium chloride so I figured I might
as well go through with this process.
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In that case, you need to adjust the overall mix a little. Let me know if you need help with that.
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Upsilon
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I probably will. But first, what role exactly does the nitrate play? Is it just used for its strong oxidizing properties, creating a hot-burning side
reaction that helps the main thermite keep going? I have seen people add sulfur to their thermite mixture to set up such a "helper" reaction with the
aluminum - if the nitrate is used for the same thing, then it should work better than sulfur since it's a stronger oxidizer, right?
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blogfast25
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| Quote: Originally posted by Upsilon |
I probably will. But first, what role exactly does the nitrate play? Is it just used for its strong oxidizing properties, creating a hot-burning side
reaction that helps the main thermite keep going? I have seen people add sulfur to their thermite mixture to set up such a "helper" reaction with the
aluminum - if the nitrate is used for the same thing, then it should work better than sulfur since it's a stronger oxidizer, right?
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The main reaction:
TiO2 + 4/3 Al === > Ti + 2/3 Al2O3
... produces little heat, only about 200 kJ/mol of Ti. This is far short of what's needed to obtain the reaction products in molten form and allow
good separation between metal and slag.
To boost heat and reach the needed end-temperature a heat boosting system is used: KClO3, KNO3, NaNO3 and CaSO4 are all usable. They rely on the
reaction (here for KClO3):
KClO3 + 2 Al === > KCl + Al2O3 which is VERY exothermic. With KClO3 + Al, you need about 1 to 1.2 mol KClO3 per mol of TiO2 to reach between 2600
to 3000 C end-temperature.
I'll post my NaNO3 based formulation tomorrow (I need to look it up).
Sulphur is really only used for the SiO2 thermites, it doesn't work for Ti.
Further reading (my essay on this method):
http://developing-your-web-presence.blogspot.co.uk/2008/10/o...
[Edited on 5-10-2015 by blogfast25]
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Upsilon
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| Quote: Originally posted by blogfast25 |
The main reaction:
TiO2 + 4/3 Al === > Ti + 2/3 Al2O3
... produces little heat, only about 200 kJ/mol of Ti. This is far short of what's needed to obtain the reaction products in molten form and allow
good separation between metal and slag.
To boost heat and reach the needed end-temperature a heat boosting system is used: KClO3, KNO3, NaNO3 and CaSO4 are all usable. They rely on the
reaction (here for KClO3):
KClO3 + 2 Al === > KCl + Al2O3 which is VERY exothermic. With KClO3 + Al, you need about 1 to 1.2 mol KClO3 per mol of TiO2 to reach between 2600
to 3000 C end-temperature.
I'll post my NaNO3 based formulation tomorrow (I need to look it up).
Sulphur is really only used for the SiO2 thermites, it doesn't work for Ti.
Further reading (my essay on this method):
http://developing-your-web-presence.blogspot.co.uk/2008/10/o...
[Edited on 5-10-2015 by blogfast25] |
Thanks. With regards to the lithium nitrate electrolysis, I think I'm going to run into some density issues trying to do it under mineral oil. First I
don't know the density of molten LiNO3; however its density in solid form is 2.38 g/cm3, so I don't imagine its density would drop below the 0.8 g/cm3
of mineral oil. The molten lithium will certainly float, though. I would have to develop some upside down trap to collect it, but it would be hard to
keep it under mineral oil after collecting. Perhaps petroleum jelly would work until I can get it sealed under an inert gas.
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elementcollector1
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| Quote: Originally posted by Upsilon |
Thanks. With regards to the lithium nitrate electrolysis, I think I'm going to run into some density issues trying to do it under mineral oil. First I
don't know the density of molten LiNO3; however its density in solid form is 2.38 g/cm3, so I don't imagine its density would drop below the 0.8 g/cm3
of mineral oil. The molten lithium will certainly float, though. I would have to develop some upside down trap to collect it, but it would be hard to
keep it under mineral oil after collecting. Perhaps petroleum jelly would work until I can get it sealed under an inert gas. |
Why not shape the cathode like an upside-down metal bowl, or some such? That way it would be produced and collected at the same time.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Upsilon
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That's what I'm thinking. I don't know what to do with it, though. I won't be able to seal anything under inert gas for a couple of months. There's
really just no good way to display it until then that I can think of; smothering in petroleum jelly isn't very good, and if I put it in a vial full of
mineral oil, it'll just float to the top and be hidden by the cap.
[Edited on 5-10-2015 by Upsilon]
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blogfast25
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| Quote: Originally posted by Upsilon |
That's what I'm thinking. I don't know what to do with it, though. I won't be able to seal anything under inert gas for a couple of months. There's
really just no good way to display it until then that I can think of; smothering in petroleum jelly isn't very good, and if I put it in a vial full of
mineral oil, it'll just float to the top and be hidden by the cap.
[Edited on 5-10-2015 by Upsilon] |
Have look at SM's library:
http://library.sciencemadness.org/library/index.html
I think Georg Brauer's 'Handbook of Preparative Inorganic Chemistry' has a procedure for elemental lithium.
A dome shaped cathode would only work if you can coat the outside with some insulator. Even the there would be issues with current pathways, I think.
[Edited on 5-10-2015 by blogfast25]
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Upsilon
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Good news; I'm getting a lot of extra work hours in the coming month, so I'll have more spending money to get materials sooner than later!
Unfortunately this means that I probably won't get around to doing anything until this weekend.
I'm going to be doing a lot in the coming months. I am hopeful that I will find time to build an arc welder/furnace, an induction heater, and a
vacuum/inert gas glovebox. I'll also be working on the element collection. If anyone has any ideas for useful projects under around $200-$300 USD,
I'll take suggestions.
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Upsilon
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Holy crap, I didn't even see your post until just now. Must have posted shortly before my last post. I'll definitely have to look into that; I'm
having trouble thinking of a practical collection method.
Instead of using valuable nitric acid to make the lithium nitrate, I'll probably instead react the lithium carbonate with citric acid, then combine
with calcium nitrate to precipitate out insoluble calcium citrate. The issue is that I don't know how soluble lithium citrate is, but it should at
least be more soluble than the lithium carbonate itself.
EDIT: After looking around I have found this glass cloth electrical tape capable of acting as an electrical insulator as well as withstanding the high
temperatures. If it works correctly, I should be able to run a wire (insulated with this tape) into an upside-down test tube with the mouth submerged
into the molten LiNO3, filled the rest of the way with mineral oil. The wire would be connected to a short graphite electrode. Here is a poorly-drawn diagram of my thoughts. Dark blue is lithium nitrate solution, light blue is mineral oil, gray rods are graphite
electrodes, and red wiring, is, well, wiring. The wire submerged in the molten lithium nitrate will obviously be insulated with the glass fabric
electrical tape.
This is of course assuming the glass fabric tape will actually work for this. Since it is apparently a form of fabric insulation, I don't know how
well it will keep a watertight seal. I am also slightly weary about using a borosilicate glass test tube for this, but it should be OK at 255C when
lithium nitrate melts, though it will be cutting it close (I will be using a porcelain crucible for the actual lithium nitrate container).
[Edited on 7-10-2015 by Upsilon]
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Upsilon
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I had some time today so I started making the lithium citrate as a precursor to the lithium nitrate I need. I reacted lithium carbonate with citric
acid and the reaction proceeded as expected, except that the aftermath solution is extremely syrupy. I'm guessing this is just undissolved lithium
citrate?
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