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How to make Rhodium sulphate / Rhodium Plating Solution



Q. How can I produce rhodium sulphate in lab?

amin darvishi
- isfahan iran
February 16, 2023


Q. I boil sulfuric acid and rhodium powder and my black powder turns to red but didn't dissolve in sulfuric acid?
What is this red powder? rhodium sulphate?

amin darvishi [returning]
- isfahan
March 4, 2023


https://pubmed.ncbi.nlm.nih.gov/11708088/

http://www.ajchem-a.com/article_92164_e9bc6183bdc619dec8940a4e557fd5a4.pdf

https://patents.google.com/patent/CN103341639B/en

A. Hi Amin. I have never made rhodium sulphate, and can't be of much help except to suggest that you google the subject and spend some substantial time on it ⇨
Dissolving rhodium into aqua regia (certainly not simply sulfuric acid) is not as easy as it sounds. Even in fine powder form, it passivates and stops dissolving. If you choose to continue, and hopefully you haven't risked more than a small test tube of solution yet, google "dissolve rhodium in aqua regia" and really study it; rhodium doesn't fully dissolve without very careful chemical or electrochemical coaching.
Good Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

P.S.: please turn on javascript in your web browser, Amin. Proper interaction with websites these days requires it; your messages got to us in fractured form, and we hope we interpreted them correctly and attached them to the thread that you intended.



⇩ Closely related postings, oldest first ⇩



Dear Whoever can Help,

I own a precious metals refinery and desperately need to know how to make rhodium plating and pen plating solutions. I know someone out there knows. Please help.

Jose a Figueroa
- Hallandale, Florida
2002


Do you want to know how to actually make the solution or are you in need of a Rhodium plating setup to plate pieces?

Sam Obermeister
rhodium plating solution supplier - Brooklyn, New York




Q. I want to make rhodium plating solution. I have rhodium metal and want solution of 2 gram rhodium for 100 ml solution (for plating batch). How one can help me?

Best regards

Dirk Blomme
hobbyist - Kortrijk, West -Vlaanderen, Belgium
2004


A. Hi, Dirk. Hobbyists might tend to assume that users make plating solutions from commodity ingredients because that's what they saw in science class in school -- but that's not the way it's done 99.9% of the time.

Rather, they buy rhodium plating solution. For one thing, the solution will be nearly worthless if it's contaminated with other chemicals, and rhodium is so fabulously expensive to put at risk that way. I'm confident that jewelers in your area buy rhodium plating solutions and can steer you to a vendor. Good luck!

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


thumbs down sign I don't think you answered Dirk's question.

Gui Salducci
- Natick, Massachusetts
April 12, 2022


thumbs up sign Hi Gui. You're right, thanks!
Still, the way to Carnegie Hall is practice, practice, practice. With Zinc at $.13 per ounce, Copper $.30, even Nickel at an historically high $1 per ounce, Dirk should at least practice his hand at making other plating solutions first to learn the ropes in the art & science of making plating solutions.

Rhodium metal currently costs $19,000 per ounce -- it's more than half a million times as expensive as zinc. As curator of the forum I feel obligated to warn self-announced hobbyists, before they are inadvertently led down the garden path, that their experiments will doubtlessly greatly reduce the value of their precious metal holdings :-)

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey




Q. I want to make rhodium plating solution. I have rhodium metal and want solution of 2 gram rhodium for 100 ml solution (for plating batch). How one can help me?

Best regards

Ibrahim GUNEY
- Erzurum, Turkiye
2004


simultaneous replies

A. Simple rhodium plating bath:
2,5-5 gm rhodium (dissolve it in Aqua regia, then evaporate and add to bath)
20-60 ml sulphuric acid (or phosphoric)
1 lit water, up to 1 A/dm2, 20 °C temp. platinized titanium anode

Goran Budija
- Cerovski vrh Croatia
2004


A. DEAR DIRK

IT IS A COMPLICATED PROCEDURE AND EASIEST ONE IS -REF A BOOK.

1-MAKE A FOIL OF YOUR RH
2-ACTIVATE IN HCl(1:2) WITH AN AC CURRENT OF 50 AMP AC/SQ.DM FOR 5-10 MINUTES
3-RINSE
4-IMMERSE IN H2SO4 50 G/L, AND SWITCH ON POWER AC <20 VOLTS FOR 10-20 MINUTES AND 20-30 AMP/SQ DM, AFTER WHICH YOU ADD H2O2 INTO THE ELECTROLYTE (ADDITION WHILE THE POWER IS OFF) AND THE TEMPERATURE SHOULD NOT BE HIGHER THAN 16 C. TO CONTROL YOUR CONCENTRATION OF H2O2 -HYDROGEN PEROXIDE- YOU SHOULD CONSIDER A CURRENT OF 20 AM/SQ.DM WELL DISSOLVE 0.002-0.005 G/SQ.CM PER HOUR. AND CONSUME 0.002 G/SQ.CM PER HOUR. RECOMMENDED CONCENTRATION OF H2O2 IS 0.8-1.0 G/L.
5-AFTER DISSOLVING BOIL THE SOLUTION TO REMOVE EXCESS OF THE HYDROGEN PEROXIDE.

HOPE THIS MAY HELP, AT LEAST AS AN INFORMATION WISE, AND GOOD LUCK AND GOD BLESS

Cair Shishani
Khair Shishani
aircraft maintenance - Al Ain, UAE


thumbs up sign That was helpful. Thank you, Khair.

Gui Salducci
- Natick, Massachusetts
April 12, 2022


thumbs up sign This is helpful, Goran.

Q. Can you please tell me what you mean by 1 A/dm2? Thank you.

Gui Salducci
- Natick, Massachusetts
April 12, 2022


A. Current density = 1 A/dm2

https://en.wikipedia.org/wiki/Current_density

Hope it helps and good luck!

Goran Budija
- Cerovski vrh


A. Hi Gui. Dissolving rhodium, even in fine powder form, into aqua regia is not as easy as it sounds. If you choose to go that way, be sure to google "dissolve rhodium in aqua regia" and spend some time on it before proceeding because it doesn't fully dissolve without careful coaching.
Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey




Q. I too would like to know how to MAKE Rhodium plating solution, and no I also don't want to buy already made solution for any chemical companies or jewelry suppliers. I instead want to make the solution.

Roger Smythe
jeweler - Knoxville, Tennessee, USA
2006




I want to make Rhodium Plating Solution equivalent to Degussa J2

Q. I want to make Rhodium Plating Solution equivalent to Degussa J2, can anyone help me?

Mayur SONI
STUDENT - INDIA
2007


A. Hi Mayur. You're certainly welcome to start with Goran's or Khair's suggested approaches.
But even the industry's trusted sources like Lowenheim's "Electroplating" [adv: this book on eBay , Amazon, AbeBooks] and Durney's Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] only offer chemical compositions for the baths in terms of "proprietary concentrates".
You might as well ask for the formula for Coca-Cola or MacDonald's special sauce as for the formula for Degussa J2 :-) Good luck.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


A. I think Mayur was just asking about the basics.

Gui Salduciis
- Natick, Massachusetts
April 12, 2022




Q. Rhodium plating chemicals: I want to make Rhodium sulphate. I have the metal with me can anyone help me in making this chemical.
Nikhil D
plating - Bangalore, Karnataka, India
February 16, 2010




Q. I am wanting to know in simple terms of how to produce a rhodium plating solution. I have rhodium metal and want solution of 2 gram rhodium for 200 ml solution (for plating batch). How one can help me? Please do me a favor, I want an early reply.

Dhirav Joshi
- Kolkata India
March 18, 2015


A. Hi Dhirav. I've already noted that users very rarely attempt to make their own solutions. And two very experienced people have already answered the basic question of how to do it if you insist nonetheless.

Please try your best to frame your ongoing questions in terms of the answers already offered. Maybe the problem is simply that it is complicated like Khair said it is, rather than "simple" like we wish it was? Best of luck.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey




Rhodium Solution Manufacturing

Q. I have virgin metal of rhodium 50 gms I want to make rhodium solution out of it how can I make it?

Dhirav Joshi [returning]
ShreeGold trading - Kolkata, India
December 21, 2017


A. Hello Dhirav, I see you asked a question along the same lines a few years ago. The process of taking Rh metal and making Rh sulphate is not easy and should not be attempted by anyone outside of the few companies that do make it. Weigh the Rh that you have. Contact a precious metal supplier that also does refining. They can assay your metal for purity. The supplier should let you exchange the metal for the solution you need. There will be a conversion charge and or a mfg. charge. If you ever have a problem with the supplier's solution you have somewhere to turn and not be pulling your hair out wondering what you did wrong to produce poor results.

Mark Baker
Process Engineering - Phoenix, Arizona USA




sidebar

Q. My name is Martin from Montreal, Canada and I have a simple technical question; I have about 20 platinum plates removed from swimming pool Salt Chlorination System cells. I removed the coating which is (I think) a mix of Ir and Rh. Got a dark powder, and added chlorine acid to it. The solution turned "green"; my question is what is this solution?

30419-1a   30419-1b   30419-1c   30419-1d  

My objective is to re-coat by electroplating the cell with the removed Ir & Rh. My second question: is it a good idea? I have plenty of pictures but I don't know what I am doing! I am not an expert in chemicals, but I can read, understand and use my judgment. I have to admit that I am enjoying playing "the Chemist" at home and having my GF yelling at me that it might be dangerous. I am a strong believer in safety first, after all it is acid.

Regards to all and thank you in advance.

martin hamel
personal use - Longueuil, Quebec, Canada
May 20, 2018


A. Hi Martin

You speak of "chlorine acid" which does not exist and you say you are no expert yet you are content to "use your judgement" when handling chemicals that professionals treat with respect.

Please listen to your GF and stop now before starting something you may regret.

If you need something to occupy your time you may enjoy watching a film --



geoff smith
Geoff Smith
Hampshire, England


A. Hi Martin. Geoff's advice is good. The first safety rule in chemical processing is never work alone; the second is to receive hands-on haz-mat training; a third is to wear proper personnel protective equipment. Are you still a strong believer after reading the first 3 tenets of the faith?

Sorry, there is no practical way to get that Rhodium and Iridium back onto the plates anyway. I think you'll find that the plates are not made of platinum, but of titanium, which is exceptionally difficult to electroplate onto under the best circumstances in an aerospace certified shop, requiring activation in special acids, followed by nickel plating, followed by special diffusion baking to alloy nickel into the titanium, followed by a Wood's nickel strike before you can start thinking about the precious metal plating. The coating was probably not applied by conventional plating the first time anyway but by Physical Vapor Deposition. Sorry :-(

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey




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