Testing for Gold and PGMs Part 2

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lazersteve

lazersteve

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Joined
Feb 27, 2007
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Location
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All,

[Edit: Safety Notice: Fusions utilizing molten sodium hydroxide are very dangerous. The proper safety gear is essential, including eye, skin, and face protection are absolutely essential. These types of fusions should only be conducted by a professional.]

Here is part 2 of the testing procedures for combined precious metals:

Test 2:

For this test you will need:

  • Sodium Peroxide (Na2O2)
  • Sodium Hydroxide (NaOH)
  • Hydrochloric Acid (HCl)
  • Ammonium Chloride (NH4Cl)
  • Distilled Water

Here's what to do:

  1. Evenly mix test material 1:1 with sodium peroxide and sodium hydroxide.
  2. Heat mix unitl liquid (980 F , 527 C) and continue heating for a minimum of 15 minutes.
  3. Dissolve cooled material into HCl and distilled water.
  4. Add ammonium chloride.

Results:

  • Gold will precipitate as a yellow powder.
  • Iridium will form a reddish-brown precipitate.
  • Platinum will drop as yellow cubes.
  • Palladium will precipitate as red-brown or olive-green precipitate.

I will be posting another test procedures for the other PGM's shortly.

The above tests are modified from Prospector Ed's guide.

Steve
 
All,

If you are interested in learning some great assay information consider this post a tidbit of free advertisment for Ed's Great guide. You can buy the entire guide on his website :

http://www.prospectored.com

Keep up the good work Ed!!


Steve
 
lazersteve said:
  1. Evenly mix test material 1:1 with sodium peroxide and sodium hydroxide.
  2. Heat mix unitl liquid (980 F , 527 C) and continue heating for a minimum of 15 minutes.
  3. Dissolve cooled material into HCl and distilled water.
  4. Add ammonium chloride.
Click to expand...

there's three material there, the ratio is 1:1:1, right?
or is it 1 part test material, 1 part 50/50 mix of sodium peroxide and sodium hydroxide?
 
Higashi said:
there's three material there, the ratio is 1:1:1, right?
or is it 1 part test material, 1 part 50/50 mix of sodium peroxide and sodium hydroxide?
Click to expand...

Good question, I would assume he meant 1 part ore to 1 part 50/50 mix of the two reagents.

Steve
 
I don't like these methods. Fusions are exceedingly dangerous to do.

I would like Steve to edit this to stress the absolute imperative necessity of eye protection. Molten NaOH has considerable vapor pressure, and is quite prone to spattering. I know it's necessary in making the iridium dioxide, but this may be a procedure best left to professionals...
 
Thanks Steve. It's just that I've personally seen what the splatter will do to skin, and it is horrible. Worse than sulfuric acid.
 
What vessel do you recommend for this procedure?. Those are (almost?) furnace temperatures.

edit: What is the purpose of this procedure?. Does it separate the elements for quantitative weighing/assaying or is it more of a mining type of qualitative assay?.
 
Lou said:
Nickel, zirconium, or silver can be used for bases. Iron to a lesser extent.


Lou
Click to expand...

Lou: Is there a low cost and sensible, accurate alternative to assay for platinum, palladium, others. akin to a fire assay for gold?.

Or really ICP , XRF, etc are the only way?.
 
There are gravimetric methods that work, but the ligands are expensive, and the chemistry often tedious.

Colorometrically, there are spectrophotometric ways to determine the purity, but again, this is often a "there is platinum in there, probably a lot of it" type test.

ICP and GFAA are really the best options.

There are fire assays that do platinum and other PGMs, but you must gold as the collector (and part with cyanide). There are also other methods using NiS.

Lou
 
I would like to find a few assaying sources for assaying pgms + gold bearing ores and buttons
for serving as umpire for the ore suppliers and the refiners of the materials we
are arc smelting. If you know what the cost of the assays are, please include that as well
for that particular assayer. Thanks folks.

Plasmasmelter
 
plasmasmelter said:
I would like to find a few assaying sources for assaying pgms + gold bearing ores and buttons
for serving as umpire for the ore suppliers and the refiners of the materials we
are arc smelting. If you know what the cost of the assays are, please include that as well
for that particular assayer. Thanks folks.

Plasmasmelter
Click to expand...
go to rick's website http://geotechanalytical.weebly.com/index.html
or contact him directly.
 
MetalMan76,

You're going to have big problems with us if you write duplicate posts or ask the same question over and over. It is quite annoying. I think this is the third time I've seen this one. More isn't better in this case. Post it once. It will get read.

Chris
 
No Chris. Your wrong. But Dont worry, Be Happy!!! :lol:

You, sir, are on thin ice. You best show due respect towards readers on this board, especially those that have the power to regulate the operation of the board.

You owe Chris an apology.

Harold
 

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