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Hafel
science forum beginner
Joined: 02 May 2006
Posts: 7
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 Posted: Tue May 02, 2006 9:57 am Post subject:
How to dissolve Pure Platinum other than Aqua regia?
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Hello, Does anyone know how to dissolve the pure platinum except of
using Aqua regia? Because while i was using the aqua regia to dissolve
the 99% Pt, i found that the reaction is slow and it cant be dissolved
eventhough i had put it in the hot aqua regia for whole day. Are there
any factors that cause the pure Pt cant be dissolved in my case (the
aqua regia thati used is consist of 3 HCL(37%) : 1 HNO3(69%).) or
there is other more effective way to dissolve the pure Pt? Thanks to
anyone who could give me some ideas about it. |
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Farooq W
science forum Guru Wannabe
Joined: 25 Mar 2005
Posts: 240
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| Posted: Tue May 02, 2006 12:59 pm Post subject:
Re: How to dissolve Pure Platinum other than Aqua regia?
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Hafel wrote:
| Quote: | Hello, Does anyone know how to dissolve the pure platinum except of
using Aqua regia? Because while i was using the aqua regia to dissolve
the 99% Pt, i found that the reaction is slow and it cant be dissolved
eventhough i had put it in the hot aqua regia for whole day. Are there
any factors that cause the pure Pt cant be dissolved in my case (the
aqua regia thati used is consist of 3 HCL(37%) : 1 HNO3(69%).) or
there is other more effective way to dissolve the pure Pt? Thanks to
anyone who could give me some ideas about it.
|
Hillebrand in "Applied Inorganic Analysis" mentions the same problem of
slow dissolution of platinum in aqua regia. Presence of other metals of
the same group renders the metal quite inert. Is you metal present in
bulk form? Can you reduce the size?
He also mentions that the best method to dissolve Pt is still hot aqua
regia. The rest of the methods are too complicated or dangerous- e.g.
dissolving the metals in an atmosphere of chlorine, alkaline fluxes
with sodium peroxide etc. The book is quite old (1955) but it is very
well written and you should be able to find it in the library.
********
I was just thinking, I don't know whether this has been tried or not.
If we electrolyze aqua regia using Pt metal as the anode and an inert
say graphite as cathode. I'd would guess the metal should readily
dissolve without even heating since the in situ generated chlorine of
Pt surface would immediately attack it. Secondly the chances of
re-deposition at the cathode are minimum as the excess of the acid
would happily dissolve the finely divided metal sponge. |
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Hafel
science forum beginner
Joined: 02 May 2006
Posts: 7
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| Posted: Tue May 02, 2006 4:34 pm Post subject:
Re: How to dissolve Pure Platinum other than Aqua regia?
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| Quote: | Hillebrand in "Applied Inorganic Analysis" mentions the same problem of
slow dissolution of platinum in aqua regia. Presence of other metals of
the same group renders the metal quite inert. Is you metal present in
bulk form? Can you reduce the size?
|
The size that i use is kind a 1mm Pt wire in 0.1 g, is that consider as
bulk form?
| Quote: | He also mentions that the best method to dissolve Pt is still hot aqua
regia. The rest of the methods are too complicated or dangerous- e.g.
dissolving the metals in an atmosphere of chlorine, alkaline fluxes
with sodium peroxide etc. The book is quite old (1955) but it is very
well written and you should be able to find it in the library.
|
Ja, i was thinking whether any other simple and fast way to dissolve
the Pt ,but since the methods are dangerous then i think i have to give
up the ideas.. Anyways thanks for ur recommended book.
| Quote: | ********
I was just thinking, I don't know whether this has been tried or not.
If we electrolyze aqua regia using Pt metal as the anode and an inert
say graphite as cathode. I'd would guess the metal should readily
dissolve without even heating since the in situ generated chlorine of
Pt surface would immediately attack it. Secondly the chances of
re-deposition at the cathode are minimum as the excess of the acid
would happily dissolve the finely divided metal sponge.
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I do have same idea with u, but never try it before. Maybe can take a
try for it, thanks... |
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rekuci@gmail.com
science forum addict
Joined: 22 Sep 2005
Posts: 98
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| Posted: Tue May 02, 2006 8:58 pm Post subject:
Re: How to dissolve Pure Platinum other than Aqua regia?
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First of all, cut it into as small pieces as possible to increase the
surface area in contact with solution.
Try microwave digesting in aqua regia in a Teflon bomb. |
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Steven
science forum beginner
Joined: 06 Feb 2005
Posts: 34
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| Posted: Thu May 04, 2006 8:15 am Post subject:
Re: How to dissolve Pure Platinum other than Aqua regia?
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Hi Hafel,
normally Aqua regina is used for separation of alloys of gold and more
precious metals. That means, that Aqua regina in normal case does solve
the gold, but leaves the platin unchanged. But within time scale, also
some platin is disolved to a more or little extent. To disolve platin
in Aqua regina, some additional elemental chlorine would be favourable
as an oxidant. That's indeed very corrosive chemistry...... |
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jtnospam@yahoo.com
science forum beginner
Joined: 21 Dec 2005
Posts: 8
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| Posted: Sat May 06, 2006 3:20 am Post subject:
Re: How to dissolve Pure Platinum other than Aqua regia?
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How about hydroflouric acid?-Jitney |
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