DeIonizedPlasma
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Tin Refining/Purification
So I recently gained access to a copy of the CRC (88th) and had fun looking through the ridiculously specific information (Did you know that the earth
loses 10^23 J/Century through radiation of heat into space?). Anyways, I happened to come across a list of low melting point alloys, one of which is
Ga-Sn-Zn.
I already have two of these, but tin is something that I don't currently have in the lab. I was unable to find anything referencing the refining of
tin here, and the only resource I found was a patent on a method of electrorefining that I would rather not spend the time to build. In this case, is
there any way to make or obtain relatively pure tin at home? I don't have any tin cans, and I would think that they aren't pure enough anyways. Any
ideas for a starting point that might contain tin in any form would be helpful.
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WGTR
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Lead-free solder is mostly tin, with either 5% antimony or 3% silver, etc. Get the stuff that is solid wire, without the flux inside. Find it in
your favourite hardware store, it's used for plumbing.
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Metacelsus
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You can buy tin ingots online (I bought an 8 oz. one once). Tin is easy to melt down, and can be granulated by dripping small drops into water.
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Magpie
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I have bought ingot tin and bismuth off eBay from which I made a low temperature melting eutectic alloy. My purpose was to have a heating bath that
could go higher in temperature than silicone oil. It must have been cheaper than Wood's metal or I would have bought that.
The single most important condition for a successful synthesis is good mixing - Nicodem
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gdflp
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Quote: Originally posted by Magpie  | | I have bought ingot tin and bismuth off eBay from which I made a low temperature melting eutectic alloy. My purpose was to have a heating bath that
could go higher in temperature than silicone oil. |
That's a very intriguing idea. Have you ever had any issues cleaning the outside of the flask afterwards, or does the alloy not wet glass at all?
[Edited on 2-19-2015 by gdflp]
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Magpie
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I never used it with a glass vessel so can't say. The picture below shows the bath on the left with the alloy in it. The middle ss vessel was used
in the bath for making molten NaOH. The copper crucible was made for the same purpose but I haven't got around to using it yet. Both of the
crucibles were silver soldered.
The ss vessels were both made from a martini shaker put to a higher use. 
The single most important condition for a successful synthesis is good mixing - Nicodem
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vmelkon
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I think certain ornaments are made of pure tin. I have one at home but I never tested it to see what it is made of.
I suppose you can buy lead-tin solder (60%-40%).
Dissolve in nitric acid. I assume this makes Sn(2+).
Lead of course will become Pb(2+).
Add a chloride salt like NaCl and PbCl2 precipitates.
You should be able to get tin metal as needle crystals by dunking in a copper wire.
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Bert
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Rotometals is about as good a deal as you will find for small quantities of 99.9% pure Tin- Prices on most items INCLUDE shipping if order is over
$99.00.
http://www.rotometals.com/Tin-Ingot-s/27.htm
They also sell several low melting alloys:
http://www.rotometals.com/Low-Melting-Fusible-Alloys-s/21.ht...
[Edited on 20-2-2015 by Bert]
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papaya
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Don't advice things you're not sure!
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blogfast25
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Chemical separation of tin and antimony can be achieved as follows.
Dissolve the Sn/Sb alloy in (weakish) Aqua Regia. It dissolves the metals to H<sub>2</sub>SnCl<sub>6</sub> and
HSbCl<sub>6</sub>.
Add KCl to the hot solution, dissolve, then allow to cool. K<sub>2</sub>SnCl<sub>6</sub> crystallises out but
KSbCl<sub>6</sub> is far too soluble and stays in solution.
From that same mixed solution Sb can also be separated out fom Sn because copper plates out the Sb but not the Sn.
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blogfast25
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It doesn't dissolve in nitric acid: it forms insoluble SnO<sub>2</sub>. It needs HNO3 + HCl. And then it forms hexachloro stannic acid.
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careysub
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They also have "popcorn" tin flake for $20/lb, which should be convenient for doing tin reductions (or for melting into an alloy composition).
http://www.rotometals.com/product-p/tinflakes.htm
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Sulaiman
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for me, a cheap source of tin is used lead-free Pewter flatware items (plates, saucers etc.) via eBay.
There may be a few percent Cu and Sb.
Selangor pewter is about 97.5% Sn, 1.5% Sb and 1% Cu.
For 'pure' tin I bought 5 oz. of 99.9% tin for GBP 7.49 incl. p&p via eBay.
Search your local eBay for 'tin 99' or 'tin 99.9'
[Edited on 21-2-2015 by Sulaiman]
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IrC
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| Quote: Originally posted by Magpie | | I have bought ingot tin and bismuth off eBay from which I made a low temperature melting eutectic alloy. My purpose was to have a heating bath that
could go higher in temperature than silicone oil. It must have been cheaper than Wood's metal or I would have bought that. |
Stick with what you made as Wood's metal is an extremely bad choice for a heating bath. 26.7 % Pb is bad enough as far as toxicity goes. The 10 %
Cadmium metal (itself toxic) which will form the very toxic oxide upon heating adds a whole new level of risk.
On the subject of the OP, Sn is so cheap at decent purity on ebay I do not see why one would wish to deal with purifying solder or some other alloy or
mix. Just buy the pure metal.
http://www.ebay.com/itm/1-Pound-TIN-metal-Ingot-99-98-pure-B...
One pound for $18.99 with $5.99 shipping.
"Science is the belief in the ignorance of the experts" Richard Feynman
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