Standard Test Solution 100mg/100ml Gold

[kadriver]

I made a standard gold test solution to test my stannous chloride and to perform other experiments.

I tried to get as close as possible to 100 milligrams of gold dissolved in 100 ml of solution as recommended by Hoke. I do not have measuring devices that are very accurate - not yet anyway.

I refined a batch of gold this week end, so I used some of the gold powder from this refining.

My scale is accurate to .1 grams.

I put a small 10 ml beaker on the scale and tared the scale to zero.

Then, using a very thin stainless steel blade, I transfered tiny amounts of dried gold powder to the beaker until it flipped from 0.0 grams to 0.1 grams.

I know this is not very accurate, but for now it will have to do.

I then added about 24 drops of hydrochloric acid to the beaker with the gold powder - just enough to cover all the gold powder.

I added nitrc acid a drop at a time and waited until all the gold powder dissolved.

I poured the resulting AuCl into a 100 ml flask, rinsing the beaker into the flask as well.

Then I added distilled water up to the 100 ml mark on the flask.

I realized that these measurments are crude, but at least I now have some standard gold test solution for experiments and testing.

There was one unexpected result: the test solution is quite yellow. I would have thought that the tiny amount of gold used would produce a much more pale yellow colored solution. I don't have one now, but I will post a photo of the solution tomorrow.

This was my first ever batch of standard gold solution, so I have no idea what to expect as far as color goes.

Does anyone have experience that can be shared with respect to the appearance of the color of a gold test solution prepared in the manner stated above?

Thank you - kadriver

 

[Harold_V]

Prepare a fresh batch of stannous chloride, following your usual procedure. What ever it may be, do it each time you build new stannous chloride. Test the gold standard solution immediately thereafter. The results of your test will become the standard by which you judge your stannous chloride. What results others achieve may not be the same as yours, so what they have to say may not have any value.

Where this becomes valuable is when your stannous starts to decline. If you test a solution that doesn't display as you expected, you would then test the stannous with the gold standard solution. If it does NOT respond as you recall, you'll know the stannous is at fault. My experience indicated that the resulting test would be less pronounced, eventually not yielding results in the least if I kept using the (declining) stannous.

Harold

 

[kadriver]

Got it Harold - thank you.

 

[kadriver]

Picture of my standard test solutions.

The gold solution was made from a batch of gold that I was refining. I took some of the powder, 0.1 gram, and dissolved in a few drops of aqua regia, then added distilled water for 100mg of gold in 100ml solution.

I orderd two grains each (edit) (1 grain = .064 grams) (end edit) of platinum and palladium and dissolved each in a few drops of AR.

Then I added distilled water to make 128mg Pt in 100ml solution and 128mg Pd in 100ml solution.

 

[kadriver]

I decided to test my standard test solutions with DMG today and I got a surprising result.

I heated the DMG dissolved in water then added it to two samples of my standard solutions, platinum and palladium.

Pt sample is the far left, Pd sample is in the middle, second Pt test is on the far right.

Both Pt & Pd samples showed precipitate - I would have expected to see precipitate in the Pd, but not in the Pt sample.

I heated the DMG to dissolve crystals that had formed. The DMG was still hot when I performed this test.

I repeated the test on the platinum sample to be sure, that is why there are two platinum samples in the photo.

This result has got me concerned - now my standard solutions are suspect.

Does anyone on the forum have experience that can be shared?

Thank you - kadriver

 

[samuel-a]

the three standart solution does indeed seems odd (first picture).
Pd at the same conc' as Pt is much much darker, brwon/red such as in your photo above.
Both the Pt and Pd bottles looks the same to me.


Pt will precipitate with DMG upon prolonged refluxed boil as blueish fluffy precipitate.
Pd orange/yellow ppt.

 

[kadriver]

I noticed the same thing - both Pt & Pd solutions looked identical.

That is why I decided to test with DMG.

Looks like the guy who sold me the platinum was deceptive.

I will have to get some platinum someplace else.

Thanks - kadriver

 

[kadriver]

I researched the seller on Ebay and found the one who sold me the palladium that was described as platinum - the tiny bar was marked platinum (I had to use a magnifier to view it).

the test with DMG clearly indicates palladium, not platinum.

It makes sense that someone is doing this - most people would never know. I was fooled because of the stannous chloride tests. But the deception is revealed by the DMG test - wow!

the seller is:

precious_metal_distribution edit spelling

http://www.ebay.com/itm/400240100542

I hope this is not one of our forum members.

This Ebay seller may not know, they may be getting it from someone else who is passing it off as platinum.

I sent this seller a message and let them know that their platinum (at least the pieces they sold me) test to be palladium, and were not platinum.

If you are looking for platinum to make standard test solutions, then I would avoid this Ebay seller until the mistake is resolved.

kadriver

 

[publius]

SNIP...
the seller is:

precious_metal_distribution edit spelling

http://www.ebay.com/itm/400240100542

This Ebay seller may not know, they may be getting it from someone else who is passing it off as platinum.

kadriver

I am happy to see that you are fair minded and willing to give the seller the benefit of your doubt...

 

[samuel-a]

wow... that's about 570% premium..... even if it was platinum.

See if he will refund you if you send back the solution :mrgreen:

on a more serious note, why not buying from someone here on the forum ?

 

[kadriver]

samuel:

I tried to buy from forum members, please see my post:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=12116

I got a couple of responses, but then the trail went cold.

Since I had all these catalytic converters coming in, I just gave in and ordered the metal off Ebay.

Its all good. I got to do some detective work with the DMG - the cost was well worth the experience - what a great way to get an education!

kadriver

 

[samuel-a]

I can sell you some foils/BB's of Pt.
PM me with an offer if interested.

 

[kadriver]

Man, I wish you would have extended that offer a while back, I would have jumped on it.

I have already bought from another seller - I told him up front that I would know right away if he was selling me palladium and not platinum - the DMG test don't lie.

He responded favorably. He knew about the swapping of palladium, and calling it platinum.

He guaranteed the item and said I would be pleased. I got a good vibe and placed the order for 2 grains at $11.65 each.

I don't mind paying this small amount as I need it to do my refining.

Soon (if all goes well) I will have my own refined pure metal.

I am learning so much. And I am learning that precious metals can be a slippery business! Maybe I can contribute to shoring that image up.

kadriver

 

[samuel-a]

That OK Kev.

Good luck with your purchase and process.

 

[kadriver]

I got the two grains of platinum in the mail.

This evening I tried to dissolve two tiny grains in hot concentrated aqua regia.

It took over 6 hours and multiple additions of acid to get the 2 grains to dissolve!

They are still not completely dissolved - they now look like tiny slices of swiss cheese (nearly completely dissolved and full of holes).

Platinum is some tough metal.

At least now I have some platinum test solution I can trust.

kadriver

 

[Harold_V]

Picture of my standard test solutions.

I salute you. You are setting excellent examples in your structured and orderly approaches to refining.
The response you're getting from the attempt to dissolve platinum is exactly as it should be. You'll notice the color will be much lighter than palladium in solution, and will be somewhat more orange than gold in solution at that level of concentration.

Harold

 

[kadriver]

Thank you Harold.

I finally got the platinum to dissolve (except for a tiny sliver).

I spent another two hours trying to get it all in solution - finally I gave up and saved the remaining sliver of metal - it was thinner than a hair.

I now have the proper test solutions - kadriver

 

[lazersteve]

Ka,

Excellent job.

I wish I would have seen this thread sooner, I would have sent you a tid bit of Pt sponge for free.

I have to admit if more members followed your methods of making standard test solutions for test comparisons, they would be much further along in their refining knowledge.

In the future PM me for any help you need with supplies.

Steve

 

[Harold_V]

I have to admit if more members followed your methods of making standard test solutions for test comparisons, they would be much further along in their refining knowledge.

I've promoted that idea, just as Hoke has, but it appears to be something that many readers don't consider of importance. Much the same as those who insist that they don't need stannous chloride. If only they knew!

Harold

 

[kadriver]

Thank you both. It is very encouraging when experienced folks such as yourselves make these positive comments to new guys like me.

Steve - I hope to have some platinum sponge from my own refining soon.

Now that I have them, and have started using them, I don't see how anyone can be involved with refining and not have these solutions to do comparison tests.

The best part of all this was; getting a piece of palladium that was sold to me as platinum - it was even marked "platinum".

I bet this happens quite frequently. The non-refining public would have never known.

If not for this forum, and if I did not know about DMG and how to use it, then I would have never known that I had been deceived.

kadriver