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topic 2236

How to make potassium gold cyanide

A discussion started in 1998 & continuing through 2017


Q. I am conducting a feasibility study on the production of potassium gold cyanide. I need information about the ff:
a. how to produce potassium gold cyanide
b. uses of potassium gold cyanide
c. cost per gram

Thank you very much.

Concepcion S. Villaverde
Metals Industry R&D Center - Gen. Santos Ave. Bicutan, Taguig, Metro Manila


A. I had the same question about this topic a few months ago. I haven't got a complete book or literature that explains producing PGC. However through some experiment with limited literature I produced PGC. The quality of PGC (percentage and purity) is still not known yet, but I have used for several months in my gold plating bath without a problem.

Next is how I make PGC:

1. Make aqua regia (75% HCl + 25% HNO3) from high grade chemical.

2. Introduce the Gold (24 kt) in bulk or small piece in warm aqua regia for fast solubility. (gold : aqua regia is about 1 : 5 weight).

3. Heat the solution, don't exceed 85 °C.

4. A long heating introduces excess HCl.

5. Heat and evaporate until you've got a concentrate like syrup that is Gold Chloride.

6. Gold chloride will become crystals when you cool the syrup.

7. Introduce a little water to dissolve the gold chloride.

8. Make ammonia solution of 30 ml Ammonia in 100 ml water concentration. (use high grade ammonia).

9. Pour the ammonia slowly to Gold Chloride until pH = 8. You will get the precipitate that call Gold Fulminate. Be careful with the Fulminate, It should not be allowed to dry because it is Highly Explosive! Danger!

10. Wash the Precipitate to remove excess ammonia. Wash several times until pH reaches near 7.

11. Make another concentrated Potassium Cyanide solution (KCN).

12. Pour the KCN into Fulminating Gold slowly with agitation until all the fulminate dissolves. You've got a solution called "Mother Liquor".

13. Heat the Mother Liquor -- in my experience not over 65 °C. Evaporate ammonia from mother liquor until no ammonia smell anymore.

14. Crystallize the PGC by continued evaporation. Vacuum will be very helpful. You don't need to evaporate all the mother liquor. When you've evaporated about 75% volume, stop the process. Collect the PGC and keep the mother liquor. Dry the PGC by vacuum. Mother liquor still can be used in the next production by mixed it with the next Fulminate.

15. Do all the processes in very good ventilation. Good luck.

Any ideas and corrections regarding my process will be welcome.

Anton Bijosono


thumbs up signWow! The detail of the response to the PGC question was incredible. Thanks to you, Anton.

Now everyone knows why it pays to buy your gold salts ready made in precisely weighed quantities. I would not take the chance of making one mistake and ruining the batch, even with the price of gold as low as it is. I prefer to let the refiners at Technic, LeaRonal, and the rest of them worry about the QC. And the technical advice from those vendors on how to run the plating bath isn't half bad either.

bill vins
Bill Vins
microwave & cable assemblies
Mesa (what a place-a), Arizona 


!! When making PGC, the fulminate-mother liquor steps you should use ammonium OXALATE instead of ammonia. The gold-nitrogen bond(s) formed by using ammonia become a heat-, friction- and impact-sensitive explosive when dry, similar to the related mercury and silver compounds.

Steve Koelzer
- Sunnyvale, California USA

sidebar2 Text Selection (2004)

Q. re: Anton Bijono potassium cyanide production.

The gold cyanide produced by your method does not work well with our plating formulation; could you provide us with your gold plating recipe for trial? Many thanks.

Claude Hudon
Plating shop - Gatineau, Quebec, Canada


Q. Could anyone please tell me the type of Potassium Cyanide used in casting gold and plating, 151-50-8 and 554-07-4. Also what type of Nickel Sulfate is best used. What is the best source for these in the US?

Torry Mathews
- Ohio

A. Hi Torry. I'm not familiar with the digits you've provided for potassium cyanide (they just look like catalog numbers to me), but the short answer is that in the U.S. you can buy such supplies from the distributors of plating supplies, and that you can usually find them listed under Plating Supplies in your Yellow Pages, or in our Directory of Chemicals, the Metal Finishing Guidebook, or the Products Finishing Directory. Good luck.

Ted Mooney, Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


Q. I want to know more in detail about the potassium gold cyanide or gold cyanide. Please do reply to me and tell me what are the steps involved and what kind of stuff I will need to get this done. Thank you very much.

Mark [last name deleted for privacy by Editor]

!! Hi Mark. Anton provided an incredible depth of detail, and there has been additional helpful followup too. It is the kiss of death to a thread if people blow off those previous efforts and just repeat the question -- so please try your very hardest to frame your question in terms of what has already been said, what parts you understood, and what is still unclear to you, etc. Thanks!


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

Seeking process equipment to make Gold Potassium Cyanide


RFQ: Seeking for process equipment to make Gold Potassium Cyanide.

Kao, Andrew
Hong Kong
^- Sorry, this RFQ is outdated
     View Current RFQs

February 15, 2009

RFQ: I want to know if there is any equipment available in market for extracting gold from ore using cyanide process.

Ali Marzouqi
- accra , Ghana
^- Sorry, this RFQ is outdated
     View Current RFQs

sidebar (2000)

Q. I'm having a project and I have thought about how to make ammonia out of flowers.
Could you please tell me how to make it? That's all thanks ~! Melvin

Melvin John N. Sedano
Student - Dhahran, Kingdom of Saudi Arabia


Ed. note: That certainly shines a different light on "take time to smell the flowers" :-)


Q. Dear All,

I am a master student and my project is about potassium gold cyanide and I need to have more information if you advise some web site, book or any search about that I will appreciate.


Nuket Cakit
- Istanbul, TURKEY

Gold Plating Technology

Hi Nuket. This website has dozens of threads about potassium gold cyanide, and books about gold plating reference potassium gold cyanide hundreds of times =>
If you have a specific situation and a specific kind of information you want, I'm sure our readers can help -- but when you just want "more information", that's what books and search engines are for :-)

Luck and Regards,

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


Q. I'm studying Potassium gold cyanide too. There are two ways: chemical and electronic. The chemical way uses potassium cyanide solution gold directly; I've read it in lots of books, but its rate is too slow. I don't know the reason. Do you know the way it should be done?

Moreover, my electronic way is already finished but the product has color. I don't know the reason. Who can tell me?

Thanks very much.

Zhouwei [last name deleted for privacy by Editor]
IPM - China


A. KAu(CN)2 can be made very efficiently and pure by the anodic dissolution of metallic gold in a KCN solution. A membrane separates the cathode to prevent cathodic plating of the dissolved gold.
If the process is run hot, very pure KAu(CN)2 precipitates on cooling. The mother liquor, after replenishing with KCN, is used for the next batch.

Walther Grot
- Rockland, Delaware, USA


Q. Good night!

In first place I want to beg your pardon for the grammar mistakes, because I am writing with an electronic translator's help. I would like to know as I do to get information of the process of obtaining of the salt of gold (GPC). This process is little known in my country and consequently there is not any literature on the same.

Certain of your attention.

Marivaldo Xavier
Student - Manaus, Amazonas, Brasil

(2003) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I want to know the procedure for making gold potassium cyanide (gpc). What chemicals are used in preparation and in what quantity, temperature. Full information about gpc from start till end. Please tell me.

- Varanasi, UP & India

December 27, 2008

Q. What is best procedure for make PGC and what's the effect of PGC on human body

Mohand Saed
- Sudan

December 21, 2010 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Sir,
can you help me to prepare the gold bath using the g.p.c, I would like to know the formulation and different types / method available for different shades.

Thanking you,

- MYSORE, India

sidebar October 1, 2011

Q. So what would happen if you mix HCl with potassium ferrocyanite?

Paul Anthony
- Syracuse New York United States

October 13, 2011

!! Hi, Paul. Please try to put your question in context. Do you mean is it a good way to make Prussian Blue? Or will it explode? Will it be poisonous or tasty? Are you looking for the formula for the reaction or maybe the stoichiometric relationship?
Although I don't know the answer, we have found that readers almost never respond to such questions because they save the questioner a sentence or two at the cost of forcing the responder to deal with a dozen "ifs, ands, and buts" :-)

No one wants to spend more time on your behalf than you spend yourself. Please get back to us with your situation.

Thanks & regards,

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

June 12, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi all. Please tell me the procedure to make Gold Potassium Cyanide from gold and amount of chemicals used in each step of reaction. Please tell the secure way to handle the Gold Fulminate and potassium cyanide also.

Manoj Garg
- Ganganagar, Rajasthan, India

June 12, 2012

A. Hi Manoj.

We appended your inquiry to a thread that may partially answer it for you. But please remember that the internet is a giant one-room schoolhouse, where grade school children and post doc researchers may read the same page. Readers will frequently read discussions about things that they do not have the experience & training to safely do!

When it comes to the "secure way" to handle gold fulminates and potassium cyanide, the answer is that you absolutely must learn that in a hands-on haz-mat training course, you must never attempt to learn it via a public forum. Sorry! Good luck.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

April 6, 2013

Q. I want to set up manufacturing unit of GPC. Please help me with some standard good quality machine manufacturers.

Rohit Agarwal
- Hyderabad, India

April 8, 2013

!! Hi Rohit. If any readers offer any manufacturer names, we'll post them here. But testimonials about "how good the quality is" aren't compatible with an essentially anonymous public forum. Sorry.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

July 14, 2013

Q. I want to know if there is hydrogen cyanide released when pumping air into potassium cyanide solution when gold is being dissolved? Is there hydrogen cyanide released when gold plating if there is still free cyanide in the solution? If gold is dissolved by potassium cyanide solution can the solution be used to gold plate? Does gold have to be electrolysed into the solution or is this an alternative method to a gold plating solution? It's a bit confusing. I have also read that hydrogen peroxide speeds up oxygenation in gold cyanidization -- is there any truth to that? Thank you.

Does the process that Walther Grot describes release dangerous hydrogen cyanide? I have done similar but with cyanate and the results were incredible BUT it rubs off. Yes, it rubs off with ammonia base Brasso cleaner.

Dennis Courvier
- Detroit, Michigan

October 9, 2013

Q. Dear author
We have done all the steps mentioned above and we reached a yellowish salt and we think that it contains some amounts of chloride. What should we do to reach to PGC?
Can you tell me more about the washing step?
Thank for your help in advance.

Iman Zandi
- Tehran, Iran

November 30, 2013

Q. These posts are very helpful for the processes, but I can't find anything about what amount of KCN to water to use for making the solution. Does anyone know?

Eliana Ismé
- Amador City, California, USA

December 5, 2013

A. Hello Eliana,
Your question is how much KCN is needed to add to water to make the solution? Or is it potassium gold aurocyanide you are talking about? If it is PGC you are asking about, you can't just add it to water and expect to plate with it. Please be more specific with your question.

Mark Baker
Process Engineer - Malone, New York, USA

December 5, 2013

Q. May I pose an ethical question?

Should we be encouraging people who obviously have no knowledge of even basic chemistry to handle seriously toxic materials? In most parts of the world, cyanides are simply not available to the general public and I know of universities that will not allow degree level students to use it.

Before using cyanides, or any other chemical, you should be able to answer the question - Do I know what to do when (not if) something goes wrong?

With cyanides there may be no second chance. This area should be strictly left to the professionals.

geoff smith
Geoff Smith

Hi Geoff. We actively discourage amateurs on this and dozens of very similar threads. We remind them that the internet, like a library, is a one-room schoolhouse where they will read about stuff they can't safely do. We suggest books, and we explain the need for hands-on haz-mat training and chemistry knowledge, etc. When they read your response (from someone who is a true cyanide expert), I hope it completely dissuades them! Still, people sometimes cannot be dissuaded.

I think it is an excellent idea to keep telling people "Don't attempt this at home", but I don't find it realistic to believe that erecting a wall of silence can sufficiently deter them as to make the world a safer place. If they simply google "how to make cyanide" there are instructions with no warnings at all written by deliberate troublemakers. We have several threads here on "gold recovery" where we are criticized (even by trained first responders!!) for not providing enough detail to untrained amateurs, thus (per their claim) encouraging people to experiment with no knowledge instead of with some knowledge. We can't win :-)


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

September 25, 2014

I think cyanides could be handled safely by an informed layman. One just must never, ever, forget what one is dealing with.

dave wichern
Dave Wichern
Consultant - The Bronx, New York

Hi. I have to disagree with you Dave.
When I taught safety in plating, I tried to draw interest by starting with this question: "A person who is well trained in safety [will / will not] sometimes do unsafe things?"

It usually took some in the class a while to get on board with the right answer, but when they did they realized why we need disciplinary rules for not wearing PPE, for working alone, for not ticking the checklist, etc., because someday somehow they absolutely will "forget what they are working with". I don't think anyone has the necessary self-discipline to work safely 100% of the time on their own when the dangers are that omnipresent :-)


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

September 16, 2014

Q. Dear Anton, could you please inform the percentage (ratio) of concentrate KCN solution? How many gram KCN in how many ml water? Thanks.

Can Gokten
- Istanbul, TURKEY

August 29, 2016

Q. We are doing gold recovery process from plating impurity. When we manufactured gold potassium cyanide based on the instruction above, we get salt with good purity. But, the salt becomes yellowish color after 12 hours of storage.
Can you tell us the reason for this and what mistake we would have done, during our manufacturing process?

ragu elango
- chennai tamilnadu India

August 31, 2016

A. Hello, are you using plain ammonia or ammonium oxalate? What is your drying process? Vacuum drying is a necessity.

Mark Baker
Process Engineer - Phoenix Arizona

Preparation/Extraction of Potassium Cyanide

December 2, 2017

Q. I am a research student and want to extract gold for which I require potassium cyanide. How can I prepare/extract potassium cyanide? From which source will the extraction be fruitful? What is its cost per gram?

Sana Shaikh
- Mumbai, Maharshtra, India

December 2017

A. Hi Sana. You should probably buy the potassium cyanide rather than attempting to make it. But check that your research facility permits the making or using of potassium cyanide and that you have the proper safeguards on hand, and have received hands-on haz-mat training first. If you must make it, a google search will instantly reveal a number of troublemaker sites which teach how to make cyanide and even worse poisons at home; you start by making ferrocyanide.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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