Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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What dissolves gold
Q. Hi there
I have heard that a mixture of hydrochloric acid and nitric acid can dissolve gold, but I am not sure of the percentages.
I am a metallurgist with ten years of experience in gold processing from broken ore, so feel free to ask me questions if you need help.
Thank-you,
metallurgist - Germiston, South Africa
2006
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A. Please mixture 1 part HNO3 (nitric acid) + 3 parts HCl ( hydrochloric acid. telkom company - Gresik, Eastjava, INDONESIA 2006 A. Hi Grant, process engineer - Malone, New York 2006 A. Hi Grant,  Freeman Newton [deceased] (It is our sad duty to advise that Freeman passed away April 21, 2012. R.I.P. old friend). 2006 |
Q. I think gold is soluble in cyanide also? Being a metallurgist in that field could you confirm this?
Guillermo MarrufoMonterrey, NL, Mexico
2006
A. What dissolves gold?
Both are right: aqua regia is the mixture of nitric and hydrochloric (aka muriatic) acids. Meaning "royal water" this acid mix was used to dissolve gold and in the process would invariably stain the clothing worn around the mess a purple color, leading to the expensive "royalty" color of purple.
I ask why to do this?
We do it as a part of the refining process to take a lower karat gold (10 or 14 K for example) and retrieve the pure (24 K) back again.
- Islamorada, Florida, USA
2006
A. A solution of potassium iodide and iodine dissolved in water will dissolve gold. This is a standard etch that is used in patterning gold during photolithography in the electronics industry. Try 40 g of potassium iodide, 10 g of iodine in 400 ml of water. Don't know if it will work for your application but the chemicals are certainly easier to work with than aqua regia.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
2006
A. Mercury will dissolve gold, too. To retrieve the gold, you must boil-off the mercury, though...and deal with the associated hazards of this process.
Adam Christopherson- Raleigh, North Carolina
2006
Q. Hello
I want to synthesis gold nanoparticle, but I can't work with HAuCl4 because it is very corrosive, I want to dissolve gold in noncorrosive solution, do you propose a solvent?
Thank you
- Tehran, Iran
2006
Q. Hi all, I was wondering if instead of using concentrated hydrochloric acid, could I use brick cleaner for aqua regia? brick cleaner is about 30% hydrochloric acid. its hard to find a supplier of concentrated hydrochloric acid in the UK.
any thoughts?
hobbyist - England
July 7, 2011
Q. Hello I have a big problem for dissolving gold because I don't know the percentage of HCl and HNO3 to dissolve gold.
I read in a article that strength of HCl acid must be 32-37% to dissolve gold but I don't know how much must be percentage of HNO3 acid. Please let me know.
- velenje, Slovenia
October 8, 2012
A. Hi Denis.
The mixture is called "Aqua Regia", so you should find many references to its formulation, but on this page two readers have said it's 1 part by volume of nitric acid to 3 parts by volume of hydrochloric acid. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 8, 2012
Q. I have prepared gold nanoparticles using bacteria, the powder obtained after lyophilization is Gold nano-particles but they are not dissolving in distilled water ethyl acetate, ethanol and even methanol
[affil links].
Please could somebody guide me about what solvent should I use?
student - lahore, Punjab, Pakistan
October 24, 2016
November 7, 2016
A. Hera,
I would imagine the best you could hope for with gold nanoparticles is a colloidal mix. To actually dissolve gold (under the usual definition for "dissolve") you need something like aqua regia.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
Q. Hi everyone,
Does phosphate buffer saline can dissolve gold nanoparticles?
- Kedah, Malaysia
December 12, 2016
A. Hi Zukhi. I don't really know what you mean by "phosphate buffer saline", but I wouldn't expect a phosphate or a buffer or a saline solution to dissolve gold. Please explain your situation.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2016
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