# Testing for Rhodium



## lazersteve (Mar 12, 2008)

All,

Last night I did some experimenting with some Rhodium samples I have. I researched some literature and found a fairly easy way to test for Rhodium in solution and it also works for unknown complexes that are soluble in water or acid.


Add a drop of the solution (which contains no gold, pt, or pd) to be tested to a test tube with three drops of water. If testing a solid complex transfer a few grains of the complex into the test tube using a clean cotton swab.
Add 1 drop of stannous chloride solution to the sample.
A color change may occur which indicates platinum or palladium (yellow-orange to blue-green) when the stannous is added to a complex dissolved in water. This should not adversely affect the test, but you will need to become familiar with this condition to properly judge the Rhodium content of the solution/complex when Rhodium is also present.
Heat the test tube for a few moments over a heat gun on low or a Bunsen burner. DO NOT overheat as the liquid may bump out of the test tube!
If the solution is free of Pt and Pd you will see a golden yellow-orange color appear when the solution warms. If Pt or Pd are present the colored solutions will lighten towards golden yellow-orange when it warms. Typically 10-20 seconds of heating are required to reach this point.
Remove the test tube from the heat source when the color changes as mentioned above. 
As the solution cools the color will change to a deep red color, between rose red and blood red depending on the Rhodium concentration.
Test detects 6ug (micro grams) per mL concentrations and greater of Rhodium in solution.

I have verified this test works and have learned how to identify Rhodium complexes and solutions even when Pt and Pd are present. It takes a little practice, with known control solutions, but it's not difficult to learn. I'm going to produce a video of the testing procedure and post it on my website soon.

Here's a photo of the test results:







The vial on the left is positive for Rhodium and the one on the right is positive for Platinum, both were tested with ordinary stannous chloride.

Steve


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## Noxx (Mar 13, 2008)

That's great. Thanks for the input.


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## Irons (Mar 13, 2008)

I like that color.


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## Lou (Mar 13, 2008)

Excellent work Steve, I figured as much would come from your experimentation!!

So tell me, how did you do it, mix up the soluble RhCl3 with some Pd and Pt compounds?
Rather nice to have pure materials to work with, isn't it? Helps with making standards 


Lou


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## lazersteve (Mar 13, 2008)

Lou,

I started out learning the process with the known samples, then I moved on to testing my unknown complexes and odd colored (orange, rose, and red) powders that tested positive to stannous for Pt on a cotton swab. 

The Rh you see in the left test tube above was the result of some experiments that I performed on some medical scrap. The Pt on the right was a flesh colored (very light tan-yellow like in Stefan's Tutorial) powder that I precipitated with NH4Cl from one of my cat tests.

I have many grams of assorted colored powders that I have produced while working with the cats and making the Pt and Pd DVD. 

Learning this test has allowed me to identify no less than three solutions in my lab that contained Rh and two powders that I had previously produced.

I can not stress the importance of everyone knowing how to use your test solutions when refining. If I had not learned this test process, I may have tossed out three Rhodium containing solutions as barren. I'm constantly testing my solutions and powders as I work. I will never toss the baby out with the bath water as long as I'm adept at using my test solutions. :wink:

Steve


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## blueduck (Mar 13, 2008)

Something so simple it is missed by looking to hard for the answer..... square one is always the best place to start.... 

I aint given up yet, though I have slowed down some..... the weather here is wet, spring freezing at night and some days topping next to the 70F mark..... the creeks and the river still have ice on the banks though, and the steelhead are running, though i aint tried set a hook into one this season..... I am more or less just waiting for the gravel to thaw so go play with some "free gold" roaming again, and try to pick up a few plats out of the creek as well since they abound around here.

Thanks for the test procedure!

William


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## arthur kierski (Apr 30, 2008)

great test --congratulations on your work---you are a reference to me
thanks lazersteve------
arthur


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## markqf1 (May 14, 2008)

Great work Steve!
Keep us posted on your progress with the video.

Mark


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## eagle2 (May 26, 2008)

Thank You Steve.

Its really helpful to see the exact shade of red that Rhodium produces.

Al


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## justinhcase (Apr 5, 2014)

Very concise explanation.
I look forward to trying it if ever I am lucky enough to think I have found any Rh
Much thanks


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## blueduck (Feb 18, 2016)

I knew we had discussed this before, I have an hard rock ore body that is complex and reads high in Rh in a recent assay. Now to find a suitable leach to put Rh into solution (am searching the forum before asking for duplicate responses)

William
Idaho


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## FrugalRefiner (Feb 18, 2016)

Mixed foils from plating wire.

Dave


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## Lou (Feb 18, 2016)

blueduck said:


> I knew we had discussed this before, I have an hard rock ore body that is complex and reads high in Rh in a recent assay. Now to find a suitable leach to put Rh into solution (am searching the forum before asking for duplicate responses)
> 
> William
> Idaho




Unfortunately, pyrosulfate fusions are usually not so good on silicates. As for the Rh component, you might try fusion with sodium peroxide in zirconium (or preferably gold or silver) crucible. That'll put even Ir into solution.


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## blueduck (Feb 20, 2016)

Thanks Lou, it definitely is a complex ore, and through research, testing, trial and dead ends find that the Rh has to be removed to get to the gold silver, and the other PGMs ..... Compounding problems show 130 toz per ton of arsenic that will need to come out and be treated appropriately along the way as well (scrubber should keep us healthy) but that Rh will turn the nitric we wanted to use inert from leaching the other metals out if not removed.... 

We can crush and table this ore and recover 3/4 toz of both Au and Pt but have to grind it below -200 which takes forever and two days to run acrost the M7 wave table as we have it set up currently..... Hence the need to leach the layers as we get to them, with Rh being first layer to remove. 

I absolutely admire the knowledge of the combined posters on this forum and while I stepped away, I have peeked back in a few times, just was not set up to do much of what was discussed several year back any longer, and now this presents itself as a new chapter and challenge in my life!

William
Idaho


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