# Standard Test Solution 100mg/100ml Gold



## kadriver (Dec 11, 2011)

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


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## Harold_V (Dec 12, 2011)

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


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## kadriver (Dec 12, 2011)

Got it Harold - thank you.


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## kadriver (Jan 7, 2012)

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.


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## kadriver (Jan 7, 2012)

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


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## samuel-a (Jan 7, 2012)

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.


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## kadriver (Jan 7, 2012)

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


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## kadriver (Jan 7, 2012)

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


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## publius (Jan 7, 2012)

kadriver said:


> SNIP...
> the seller is:
> 
> precious_metal_distribution  edit spelling
> ...


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


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## samuel-a (Jan 7, 2012)

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 ?


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## kadriver (Jan 7, 2012)

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


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## samuel-a (Jan 8, 2012)

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


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## kadriver (Jan 8, 2012)

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


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## samuel-a (Jan 8, 2012)

That OK Kev.

Good luck with your purchase and process.


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## kadriver (Jan 20, 2012)

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


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## Harold_V (Jan 20, 2012)

kadriver said:


> 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


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## kadriver (Jan 21, 2012)

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


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## lazersteve (Feb 5, 2012)

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


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## Harold_V (Feb 5, 2012)

lazersteve said:


> 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


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## kadriver (Feb 5, 2012)

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


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## lazersteve (Feb 5, 2012)

It was through the use of these types of standard test solutions along with some research into testing methods that I developed this straight forward way to test for Rh in solution with stannous chloride:

Rhodium Stannous Test

Of course, I didn't invent the process, I simply laid the testing procedure out in an easy to understand process, tested my results against standard solutions, and then posted the consolidated data for everyone to use in their Rhodium refining efforts. There is nothing more valuable in refining than concise, accurate test methods, with easy to obtain chemicals (preferrably on hand already). As Harold has stated numerous times, proper testing is your 'eyes' into the solution.

Once again, great job!

Steve


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## kadriver (Feb 5, 2012)

Steve:

I have not gotten to rhodium yet - but I know it is probably already in some of my solutions.

I can look back and see the progression - first is was silver.

Next was gold, and a silver cell. then a long pause.

Then the platinum bug hit (with palladium making its appearance in the silver cell).

Finally arriving at rhodium. 

Thank you for giving the test process for the rhodium - it seems the logical next element that will be showing up in my shop - and that right soon.

kadriver


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## k2CO (Mar 15, 2012)

kadriver said:


> 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.
> 
> ...



First posting for a fairly new member...don't cringe yet! I've been slowly researching, reading and preparing to begin some experimentation on recovery and refining...the intuition-building phase. I was just going over how to make up the standard solutions for gold, platinum and palladium per Hoke and trying to assess what I need to create them. One big hurdle seems to be getting a small amount (2-10 grains) of pure platinum and palladium...shot or foil. 

ka...was your source from this link an ebay seller?...can you share your source? Any other advice or direction from other forum members would be much appreciated...

Thank you,

- Richard (k2CO)


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## patnor1011 (Mar 15, 2012)

k2CO said:


> kadriver said:
> 
> 
> > 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.
> ...




Ask any jeweller. I got mine from jeweller in city 1/4 or 1/2 gram is more than what you need. Pd dissolve in AR without much of a problem but I had to heat Pt in AR to dissolve it faster. I got 3-5 pieces of hair thin like Pt wire, total length about 5cm - weight not really measurable but when I placed it in AR and heated it gave me strong reaction when tested with stannous. And wires did not even dissolve completely.


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## Lobby (Mar 27, 2012)

Harold_V said:


> kadriver said:
> 
> 
> > Picture of my standard test solutions.
> ...



I like this post. And I like this thread.


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## manneke_pis (Apr 24, 2012)

Hi ..

I am interested in Standard Solutions as well.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=13998

after some research ideally I think Gold Standard Solution colour should be like :


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## rewalston (Jun 12, 2012)

I have an oddball question. I've seen/read the instructions for making gold standard solution. A certain weight in a precise amount of aqua regia. Considering that nitric acid is rather expensive and really difficult to get, can HCl/bleach be used to make the standard solution instead?

Rusty


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## Geo (Jun 12, 2012)

rewalston said:


> I have an oddball question. I've seen/read the instructions for making gold standard solution. A certain weight in a precise amount of aqua regia. Considering that nitric acid is rather expensive and really difficult to get, can HCl/bleach be used to make the standard solution instead?
> 
> Rusty



short answer, yes. AuCl is AuCl however you slice it.


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## rewalston (Jun 12, 2012)

Thank you Geo, that was what I was thinking but I thought I'd ask anyway. Now all I need to do is get to the point where I can make some. Still collecting...never ending battle 

Rusty


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## g_axelsson (Jan 26, 2013)

I'm slowly reading up on all posts that happened during my two year hiatus from the forum. I will read all the posts on the forum... eventually. :mrgreen:

I just thought this is such a good thread on testing solutions it deserved to be brought back to life now and then.

There were just one tiny thing I noticed...


kadriver said:


> My scale is accurate to .1 grams.
> 
> I put a small 10 ml beaker on the scale and tared the scale to zero.
> 
> ...


By doing it that way you may have as much as 50% error in concentration even if the scale had no error in measurement. Bear with me, I'll try to explain what I mean.

For a scale that measures digitally it could do it in two ways:
- Round to nearest scale point.
0.00-0.05 -> 0.0g
0.05-0.15 -> 0.1g
0.15-0.25 -> 0.2g
...

- Truncate the scale
0.0-0.1 -> 0.0g
0.1-0.2 -> 0.1g
0.2-0.3 -> 0.2g
...

If you round to the digital scale used then your scale have an error of 0.05g, if you truncate then the scale have an error of 0.1g, therefore most digital scales uses the rounding method.
So when you measured your gold you might have gotten only 0.05g.
I suggest you would measure it this way...
1. put two small beakers on your scale and tare.
2. in the first beaker add gold powder until the scale starts to flip between 0.0 and 0.1g
3. in the second beaker add gold powder until the scale flips between 0.1 and 0.2g
4. use the gold in the second beaker to make your testing solution

This will also reveal how your scale measures. If the gold in the beakers seems to be equal then it uses the truncating method, if it is twice as much in the second beaker then it uses the rounding method.

Göran


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## jonn (Jan 26, 2013)

Kadriver,
I just want to compliment you on a job well done, I have been following some of your other posts and must say I am very impressed. It's nice to see everything is well explained and I still can't figure how you keep everything so clean  
Great job, please keep it up. Thank you


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## Gratilla (Jan 26, 2013)

kadriver said:


> My scale is accurate to .1 grams.
> 
> I put a small 10 ml beaker on the scale and tared the scale to zero.
> 
> ...



Or, or, or...

Weigh out 1gm (ie one gram) gold powder, dissolve in 1 liter AR, take out 100ml for standard solution and recover the gold in the rest. Voila.


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## Geo (Jan 26, 2013)

1g in 1L is very diluted. 1g in 500ml may be better. you need the standard to be very clear. if you need a dilute standard, you can always dilute with water.


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## Gratilla (Jan 27, 2013)

I simply multiplied all the initial quantities by ten - in order to minimize the percentage of error.

I'll be making my own set of standard bottles (1ppm to 10ppm) in a week or so and have been doing some thinking. <ouch!>


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## kadriver (Jan 29, 2013)

The test solution is used primarily to determine the potency of my stannous chloride solution. If my stannous test solution is old or giving weird results, then I can go to a know sample of gold test solution and test the stannous.

When I make a new batch of stannous chloride, I test it immediately using my standard gold test solution, then note the darkness, color, and general appearence of the reaction.

I can then use that as a reference to see if my stannous chloride is getting weak or going to the bad.

The amount of gold in the solution is not all that critical (according to C.M. Hoke) as long as you use the same concentration each time.

The 100ml of test solution I have will probably last me for the rest of my life and it will be here long after I am gone.

Hope this helps!

kadriver


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## kadriver (Jan 30, 2013)

I stand corrected (after reviewing the book).

Hoke pg 93 says, "if your only objective is to become acquainted with the various solutions, it is not necessary to use exact measurements. But later on, when trying to estimate precious metal in a solution, it will be EXTREMELY helpful to have standard solutions made up with a definite weight of metal in a definite volume of liquid."

This makes sense when using the test solutions as a comparator to try and determine the amount of metal dissolved in a solution.

I can't recall ever doing it with gold. but I have tried to determine concentration of dissolved Pd in a solution, using a standard Pd test solution as a comparison.

I do use the gold test solution to test my stannous chloride test solution regularly.

So... The scale used to weigh out the metal to be used in a standard test solution (if it will be used as a comparator to determine dissolved metal concentration) should be as accurate as possible, probably down to at least .01 grams (my opinion, of course).

kadriver


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## kadriver (Jan 30, 2013)

jonn said:


> Kadriver,
> I just want to compliment you on a job well done, I have been following some of your other posts and must say I am very impressed. It's nice to see everything is well explained and I still can't figure how you keep everything so clean
> Great job, please keep it up. Thank you



Thank you for your kind words. It is always good to read encouraging responses for others concerning ones work efforts.

Kadriver


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## g_axelsson (Jan 30, 2013)

I agree with you fully, kadriver, for verification that your stannous is working there is no need to have any known concentration. Just keep it quite diluted so that you know it will detect weak concentrations, any stronger concentration will work too.
But for quantitative measurements then your reference needs to be of a known concentration. Any error in the reference solution will automatically add to any measurements you try to do.

I hadn't read that in Hoke... haven't read it straight through yet ...  but to do that is my new years resolution. 8) 

The absolute limit of the measurement isn't the important thing, 0.03g with 0.01g error has an uncertainty of 33% while 30g with 1g error is only 3.3% uncertain. To get a good solution with a cheap scale, take for example 10.0g gold (+/-0.05g uncertainty for a scale with 0.1g step), dissolve, add water to 100 ml which gives 0.1g/ml or 100g/liter, call it solution A. Save some as a reference if you want.
From solution A take 1 ml, add 9 ml and you have a 0.01g/ml or 10g/liter standard solution.
From solution A take 1 ml, add 99 ml and you have a 0.001g/ml or 1g/liter standard solution.
Any standard solution you don't want to keep, just pour it into your favorite precipitation beaker and turn it back to gold again. Your standard solutions that you just made have a known concentration within a few percent, even as low as below 1% error. Most errors will come from how good you can measure the liquid volumes.
Keep your solutions in closed bottles all the time as evaporation will make them more concentrated over time.

Göran


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## MEANIE (Jun 16, 2013)

I think this needs to bumped to the top. 
Seeing kadriver went to the trouble to share with us (new people) IMHO to learn the right way to start recovering and refining .
Thanks kadriver you inspire me this is what I was trying to do and I looked in all the testing threads and didn't find what I was looking for.


Todd aka MEANIE

ps Thanks AndyWilliams for linking me here.


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