SSn with iodine

[rhodiumfever]

I have leached an ore with SSN plus some iodine. 7:1 Nitric with a couple of balls of iodine per 10ml.
On neutralizing the solution with NaOH, I find that I get a pH of 1.5 fleetingly and then it reverts back to strongly acidic. I am using pH paper to monitor the pH.
Is this due to the iodine? Would it be correct to call the iodine a buffer?
I dropped the metals with Zinc powder and got very poor results. However the pH of the residue solution was about 2. Used what seemed to be a lot of zinc powder.
I have another batch that is ready. Should I neutralize with NaOH despite it seeming to take for ever?
Would appreciate any input on the above. Thanks.

 

[Lino1406]

Iodine with nitric, does nothing (nitric is a stronger oxidizer)
Zinc, beside dropping, makes solution alkaline, but you can
save Zn by raising PH to 2-3 with NaOH

 

[rhodiumfever]

Thanks for the reply Lino.
With the 2nd batch, I raised the pH to 1.5 - 2.0 which is what the SSN paper by the American Society for Applied Technology suggest.
I then dropped with zinc and this time got black/brown sludge which is taking ages to filter.
I'm primarily looking for Rhodium so I intend to to dissolve in hot AR and if there is anything left then it should be Rh!?
Have you ever used SSN (saturated saline and nitric acid)? I haven't heard anything negative about it but there doesn't seem to be a lot of information available. Some sites suggest adding iodine if you want the leach to be extra aggressive. I'm not sure how that would help, but thought it may act as a buffer to keep the pH very acidic. I would like to understand what advantages it lends to the leach.
SSN is sometimes referred to as SWAN (salt water and nitric).
Will see if I can start the AR stage now!

 

[rhodiumfever]

The brown sludge very quickly went into the AR apart from a few larger clumps. So I boiled it and the clumps also went into solution. So now there's nothing left!! Expletive, expletive, expletive.
I noticed that while I was boiling it the yellow color gave way to a orangy/red. Rhodium in solution again?
I read somewhere that oxidized rhodium will dissolve in AR. Seeing that this has just come from a strongly oxidizing SSN, could that be the case?

 

[Oz]

Why do you think you have rhodium other than the fact you have a fever.

If you had elemental rhodium boiling in AR it would still be there (as in 98% of it as a solid). This only shows that it is highly unlikely that there was any Rh to begin with.

What is up with all these people thinking they have high values of Rh lately, its not like it is back at $10,0000 an ounce or something.

 

[Platdigger]

edit

 

[Irons]

Why do you think you have rhodium other than the fact you have a fever.

If you had elemental rhodium boiling in AR it would still be there (as in 98% of it as a solid). This only shows that it is highly unlikely that there was any Rh to begin with.

What is up with all these people thinking they have high values of Rh lately, its not like it is back at $10,0000 an ounce or something.

http://www.kitco.com/pr/1037/article_04192010111627.pdf

Presenting a new-generation investment metal — Kitco Rhodium Sponge
Montreal, April 19, 2010 — In keeping with its tradition of innovation, Kitco Metals Inc. introduces a newgeneration
investment product — Kitco Rhodium Sponge.
As an industry first, Kitco is making pure rhodium powder (sponge) available to the individual customer in
convenient tamper-proof plastic bottles of one, five and 10 ounces. Now, investors can physically acquire and
trade rhodium, the rarest precious metal.
Given the increasing demand for and the limited supplies of rhodium, it is not surprising that the metal has caught
the interest of Bart Kitner, President of Kitco Metals Inc. “Everyone knows about gold and platinum. Even
palladium has gained favor among precious metals investors in recent times. But rhodium is only now coming into
its own as an investment product,” says Kitner.
Because of its hardness and wear-resistance, the metal is used in many specialized industrial applications. Its most
widespread use is in the catalytic converters of modern-day automobiles, a demand sector pegged for growth in
the world’s emerging economies.
Driven chiefly by supply-side constraints, the rhodium price reached a historic high of US$10,000 an ounce in
2008. The metal is currently priced at the lower end of its historic range and is gaining popularity as an investment
product.

 

[Barren Realms 007]

Why do you think you have rhodium other than the fact you have a fever.

If you had elemental rhodium boiling in AR it would still be there (as in 98% of it as a solid). This only shows that it is highly unlikely that there was any Rh to begin with.

What is up with all these people thinking they have high values of Rh lately, its not like it is back at $10,0000 an ounce or something.

http://www.kitco.com/pr/1037/article_04192010111627.pdf

Presenting a new-generation investment metal — Kitco Rhodium Sponge
Montreal, April 19, 2010 — In keeping with its tradition of innovation, Kitco Metals Inc. introduces a newgeneration
investment product — Kitco Rhodium Sponge.
As an industry first, Kitco is making pure rhodium powder (sponge) available to the individual customer in
convenient tamper-proof plastic bottles of one, five and 10 ounces. Now, investors can physically acquire and
trade rhodium, the rarest precious metal.
Given the increasing demand for and the limited supplies of rhodium, it is not surprising that the metal has caught
the interest of Bart Kitner, President of Kitco Metals Inc. “Everyone knows about gold and platinum. Even
palladium has gained favor among precious metals investors in recent times. But rhodium is only now coming into
its own as an investment product,” says Kitner.
Because of its hardness and wear-resistance, the metal is used in many specialized industrial applications. Its most
widespread use is in the catalytic converters of modern-day automobiles, a demand sector pegged for growth in
the world’s emerging economies.
Driven chiefly by supply-side constraints, the rhodium price reached a historic high of US$10,000 an ounce in
2008. The metal is currently priced at the lower end of its historic range and is gaining popularity as an investment
product.

Are we on the verge of another comoditiy they are selling but not able to deliver?

 

[rhodiumfever]

At last a question.
A couple of years ago I bought a sample from the same area. This was after extraction by cyanide and mercury and probably further refined with acid. Had it tested at a reliable laboratory and it was by spectroscopy analysis 20% Rh. Bought from the same guy again and it was iron!
Now skip 2 years, I've been to the place where geological information tells us it should be. Local information backs this up.
Samples I've had, keep on seeing signs of Rh, its a tricky bugger but its there. I want to know how to release it to a product that isn't heavy and bulky and is marketable.
Before leaching the ore, I roasted it but don't know of a easy way to make a reducing atmosphere for it to cool down in. Maybe this oxidized the Rh?

 

[rhodiumfever]

I tested the solution with stannous, drop of solution on filter paper followed by a drop of stannous. Got orange center with a halo of canary yellow. These tests are not very revealing to me as its the first time I've done them so have no reference point.

 

[lazersteve]

...
I'm primarily looking for Rhodium so I intend to to dissolve in hot AR and if there is anything left then it should be Rh!?...

Not necessarily true. There are several metals and non-metals that are not soluble in AR.

In fact, if you added powdered fine mesh zinc, you may have introduced Cab-O-Sil (SiO2) into the mix unknowingly. Cab-O-Sil is added to powdered zinc when shipping to stabilize it's flamability. I realize you likely did not use fine mesh zinc as all of your sludge dissolved.

My main point is that you shouldn't jump to conclusions about what the products ( and by products) of your reactions are unless you are 100% sure of what you are putting into the reaction.

Rhodium is very rare and is difficult to find and process. It is truly a separate animal than Pt and Pd as far as rarity and chemical processes are concerned.

I have posted a few simple tests for Rh. You can find them, complete with color photos of the results, in the Reactions List. You can find the Reactions List by taking the Guided Tour Link in my signature line below.

Welcome to the forum,

Steve

 

[rhodiumfever]

Thanks lazersteve, will look up those tests now. I've probably read them before, but this whole subject is a bit more complex than it first looks like. It was in one of your posts that you said oxidized Rh could be dissolved. Would I have oxidized the Rh given I roasted the ore and then leached with SSN.
There's Rhodium in them hills. Where's the faith people?

 

[Barren Realms 007]

There's Rhodium in them hills. Where's the faith people?

Seeing is belivieing. 8)

 

[rhodiumfever]

I have decided to leach a new batch with SSN without the iodine. Still not sure why the iodine would make the leach more aggressive. Sure it adds another halide floating around but what is better for attacking gold, palladium, rhodium - is it the Chlorine or the Iodine. The one sure advantage I will gain without iodine is that I wont have a yellow/brown colored leach.

 

[Platdigger]

Not true Barren, it is the other way around.... 8)

 

[rhodiumfever]

Hi Lazersteve
With regards to your stannous chloride, Rh test. Is it literally 1 drop + 3 + 1. You must be using small test-tubes. Also can you explain why one needs water.

 

[Harold_V]

This was after extraction by cyanide and mercury and probably further refined with acid.

What, rhodium? With cyanide? Why am I doubting the claim?

Harold

 

[rhodiumfever]

Really Harold there are still a lot of countries where Cyanide and mercury are the norms. Is there something I don't know, like Rhodium with cyanide will explode or something? Maybe I can sell you exclusive mining rights. No? OK then maybe you can humor me with the chemistry?

I have done Stannous Rh test 3 times with different results
1 Didn't remove the nitric which "Irons" says you should do. So we will discard that test.
2 Didn't remove gold,Pl or Pd. Solution was yellow to begin with but got brighter yellow with stannous. With heating it became orang/red and on cooling it became tea color with green/blue hint.
3 This time I added FeSo4 to remove the gold. Couldn't see any precipitate. Then added saturated Ammonium Chloride to remove the Pt, again couldn't see a precipitate. Then added DMG dissolved in alcohol and water, no precipitate.
Left this for 10 minutes to let any precipitates sink to the bottom. Took some solution from the top and did the test again. I think the yellow solution actually went paler with the stannous. When heated it lost all color completely and it didn't come back when cooled.

Whats happening. Maybe I've proven there is no Rh. I'm working on very low concentration ores at the moment because I have blown my most concentrated sample performing tests to get to know whats happening. I have about 5g of super concentrated cons left but don't want to touch them till I know what I'm doing. Also would like to save 2g or so to get a spectroscopic breakdown/assay when I get the chance. If there is Rh in this area it will be in this remaining 5g.

So if I could trouble you good people to look at my results and give suggestions, I would appreciate it.

 

[Platdigger]

Are you doing these stanis tests on paper? Or in a depresion type plate?
Forgot what you call that last one. I have one made of white plastic.
Harold had one (or has) one made of porcilin I believe.

If you are trying to do these tests in a test tube.....that could be a problem.
At least making it more difficult to get good results.
That is....I supose... unless you are using equal amounts of stanis to solution.

 

[Lino1406]

If color disappears, or becomes paler -
no PM.