Platinum Refining slide show

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lazersteve

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All,

Since I was off for Veterans Day today, I decided to take advantage of the free time and make a Platinum Slide show for the Forum...


Platinum Refining

Let me know what you think.

Here's a photo of the resulting 18.1 gram Platinum Bar:

pt_bar.jpg


The photo does the bar no justice. It's glaring to look at it is so shiny. I had to turn off the flash due to the glare.

Needless to say, I had a wonderful day today. 8)

Steve
 
Randy,

I think it was closer to 95% as I had a small fraction of material undissolved (0.4 g) and a even smaller amount stuck to the filter paper as orange powder.

Steve
 
Hello everyone,

I am new to this, I thought the video by lazersteve was excellent. I had one question about the solution used. Does it have to be aqua regia for ammonium chloride to work or can you simply use a hydrochloric acid solution and then precipitate it with ammonium chloride.

Thanks.

Dallas
 
You need the aqua regia (AR) to dissolve the platinum. Pure hydrochloric will not affect the platinum.
 
Oh ok thanks, g_axelsson.

That is what I thought, but my main problem is that I have been encountering some difficulties finding some nitric acid here in the Czech Republic. I am trying to make some calls to some chemical and laboratory stores here.

Thanks again. Dallas
 
If you don't find a source you could search the forum for "poor mans AR" or read any of the topics on how to make your own nitric from sulphuric acid and nitrate.
 
g_axelsson said:
If you don't find a source you could search the forum for "poor mans AR" or read any of the topics on how to make your own nitric from sulphuric acid and nitrate.

Concentrate Nitric Acid ?
Chris,
Nothing appears wrong with yours a first glance, except in mine I’m not leaving any Hydrogen
behind as follows:
H2SO4 + 2 NaNO3 --> Na2SO4 + 2HNO3
The big difference in my recipie is the solubility of the sodium sulfate salt (as opposed to
sodium hydrogen sulfate you produce) and the fact that my equation yields twice the nitric
acid at a higher temperature ( no dry ice, just salted ice ).
I’ve run the numbers like you did and ended up with about 160 mL of 50% nitric (give or take
a few percent) for a single mole of 96% sulfuric and using 100mL H2O to dissolve the nitre.
I won’t bore everyone with the math, but here’s my summary (PM me to see all the factors I
used to derive this reaction):

Reaction:

-Bring 100 mL of Distilled Water in a 500 mL pyrex beaker to 100 C
-Add the Nitre of your choice (202 gm K / 170 gm Na) K= Potassium NA= Sodium
Stir until Nitre is completely dissolved, let cool below boiling-
SLOWLY add 56 mL conc (96%+) Sulfuric Acid to Hot Nitre solution while stirring, DON’T
allow the solution to boil!
-Allow solution to cool to room temp (DO NOT SKIP - VESSEL WILL SHATTER IF PUT ON ICE
WHILE HOT!!!)
-When vessel reaches room temp (25 °C) put the vessel in the freezer or on a salt water ice
bath
-Let stand until temperature of mixture reaches -5 °C
-Let stand at -5 °C until all percipitate settles
-Pour the COLD solution off into glass container with tightly sealed lid DO NOT POUR OFF ANY
OF THE SALT IN THE BOTTOM!!!
-Makes ~160 mL ~50% HNO3

This acid in turn can be used to make true AR with the standard 4:1 recipie (HCl:HNO3).
Steve:
 
As a safety issue please highlight this portion of your procedure:

-Stir until Nitre is completely dissolved, let cool below boiling

The solution reacts violently if you don't let it cool a bit before adding the sulfuric. I had quite a time cleaning nitrate pudding off of my hot plate and work surface. :(

A big, down right volcanic mess and no fun at all. Let it cool below boiling is a vital step you don't want to skip.
 
Hello...I was wondering...how much would a bar like that cost in jewlery stores? More than the same amount of gold?
 
Strider said:
Hello...I was wondering...how much would a bar like that cost in jewlery stores? More than the same amount of gold?

Blink!

Blink! :?:

Can you be somewhat more specific? Which "bar" is it you speak of? If it's a Milky Way, I've not seen many of them in jewelry stores.

Harold
 
I think he's talking about the 18.1 gram platinum bar in the opening post.

It's worth about:

18.1 /31.1 * $1207 =~ $702.47

at today's spot.


Steve
 
Thanks, Steve. I didn't go back far enough for the post to make sense. That's a great example of reasons why folks should try to either quote, or make references when a statement can be vague.

Very nice piece of platinum, Steve. I have the fondest of memories of working with platinum and palladium. I found both of them to be fascinating.

Harold
 
lazersteve said:
I think he's talking about the 18.1 gram platinum bar in the opening post.

It's worth about:

18.1 /31.1 * $1207 =~ $702.47

at today's spot.


Steve
DAMN! THIS WILL BE MY FUTURE LIVING :mrgreen:
 
g_axelsson said:
You need the aqua regia (AR) to dissolve the platinum. Pure hydrochloric will not affect the platinum.

Actually, 10HCL:1H2O2 (37%HCL and 35%H2O2) will dissolve platinum at room temperature far better than Aqua regia. However, heated, aqua regia will outperform, and optimal temperature is about 70 C. For the HCL:H2O2 Mixture, optimal is 80 C, and very close to the best dissolution rates for aqua regia. This would also eliminate the need for nitric acid, and the need to Denoxx the mixture... Just my two cents. :)
 
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