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topic 34676p2

Best and Easiest way to refine gold dust to get 99.9% purity

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A discussion started in 2005 but continuing through 2020

January 30, 2013

RFQ: I am looking to buy nitric acid and hydrochloric acid to start up some experiments about gold recovery. I searched the net and could not find any. Please let me know if you know where to buy the 2 chemicals. Also, do I need a business license to purchase them?

Maj Joseph
- Charlotte, North Carolina
^- Sorry, this RFQ is outdated
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February 4, 2013

A. Hi Maj. As far as I know a consumer would not need a license to purchase things in consumer quantity that are available for sale to consumers like this. For larger quantities, you might need a license or you might simply encounter people unwilling to sell to you. Companies are justly concerned about liability if one of their products is misused, and might only want to sell to licensed industrial facilities. Regardless of laws or licenses, you need to understand how hazardous these materials are.


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

May 10, 2013

Q. Okay I am trying to extract gold from computer processors but having trouble in calculating aqua regia. Any help would be really appreciated.
I am using 10 processors as an experiment, so how much HNO3 and HCL should I add (1 to 3 grams gold is expected in it)?

trix maxer
- karachi ,pakistan

affil. link
"Gold Refining
George Gajda"

from Abe Books


November 4, 2013

Q. Dear Friends, I am getting the three type of color powders from under ground nearly 30 feet depth, and I think these powders are nearly 2700 years back. It's heavy protected inside of ground; I think this is Gold Dust. The colors are Brown, a type of Green and a type of Red. I have to search on line for Gold Dust colors same-to-same, matched these colors. Also I have to test H2SO4 and sulphate but not getting proper response. Please tell me how to test this powder.

Sri Bangaram
- Hyderbad, Andhrapradesh, India

November 12, 2013

RFQ: I want training to learn refining of gold.

bappa paul
- beldanga, west bengal

Gold recovered from PCB fingers disappeared when nitric acid was added

August 13, 2014

Q. Trying to find a correct answer to solve a problem a coworker did while we were refining Gold fingers.

He left the bucket in which the acid bath (Hydrogen Peroxide & Muriatic Acid Mix) outside and it rained. He thought the H2O would ruin the Gold for some reason so he said he added roughly 1 gallon of Nitric Acid to 3 gallons of the Acid Mix. When he did this he said it started to produce brown fumes and all of the Gold that was already off and separated from the computer parts just disappeared, turning into liquid & gas form. He pretty much went straight through to it looking like the Aqua Regia process. I could have killed him when I got back from a doc appt.

Can you PLEASE tell us there is a solution for our BIG problem. We would really appreciate your great knowledge and help us out. Great Forum btw, very helpful. Thanks and keep up the good work! We will keep checking your forum every day for your mighty knowledge in helpful answers and tips. Thanks again,

Matt Thomas
- New Orleans, Louisiana

August 13, 2014

A. You now have a lot of aqua regia with a little bit of gold dissolved in it, relatively speaking. In order to precipitate the gold with a reducing agent, such as sodium metabisulfite, you must first eliminate the huge amount of nitric acid (an oxidizing agent) that the guy dumped into the solution. Urea won't work. In your particular situation, the most straight forward way is to evaporate the whole thing down to a syrup. Get it quite hot but don't boil or you will loose gold in the vapors. Reduce the heat when the solution level gets low or the solution will splatter. Once this is done, add a little HCl and evaporate again. Repeat 2 more times. Dilute with at least 2 volumes of water. Filter. Precipitate the gold from the clear solution.

Chris Owen
- Nevada, Missouri, USA

Need detailed procedure for separating particles of gold from soil

November 24, 2014

Q. I want to know the detailed procedure for removing gold particles from soil.

Raj Jagdishbhai Gandhi
- surat,gujarat,india

November 2014

A. Hi Raj. I don't understand the background behind your question. Please spend more words on your question than you expect people to spend on the answer. Is this a science project question for school? Are you referring to gold panning? You want a detailed procedure for gold panning? Thanks.


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

March 7, 2015

A. Hi mr raj gandhi,
First you have to detect exact % of gold from your soil using XRF or from any lab report. Then only could I suggest a process which is tecno-economically better for you.

bhupesh mulik
- mumbai,india

December 28, 2014

Q. My name is ramyar. Please tell me tow powder chemical for recovery gold scrap. Away cyanide, Thank you very much.

fryad fwad
qandel - slemany.kurd.iraq

December 2014

? Hi Ramyar. More words please! There are some typos in your question but I can't quite figure it out. Are you looking for how to recover gold from electronic scrap without using any cyanide?


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

March 7, 2015

A. Hi ramyar,
Please explain about your gold scrap; whether it is jewellery gold scrap or electronic waste (computer IC) scrap?

bhupesh mulik
- mumbai,india

March 30, 2015

Q. Sir
How to Convert old gold to pure gold? How to Calculate the wastage when converting old gold to pure gold

lakshman murty

May 31, 2015

Q. I refine gold in an easier way by mixing gold in it. I make it in 6 carat gold, then pour into the water. Then I put it on the heat with the HNO3 for 2 hours. I get the pure gold of 99.80, but sometimes it has lead or tin of .20 percent. So how can I clean that lead or tin in this process? Please answer, I need it urgently.

devakar aggarwal
job - delhi india

July 18, 2015

A. Dear devakar,
You are following inquartation; if your metal contains tin or lead go by aqua regia process. You will get better purity.
Does your scrap metal contain lead or tin, please check?

bhupesh mulik
cac admixtures - mumbai,india

Pure gold grain is wrong color

July 2, 2015

Q. I have made grain thousands of times from scrap. However this grain has come out much darker in colour. It still tests by XRF and assay as 99.96. How to change the colour?

Nathan Rivers
- United Kingdom

July 3, 2015

A. Nathan,

Put a little grain in a little hot 10% sulfuric acid for about 5 minutes, rinse it, dry it, and compare the colors. If it lightens up, the dark color on the surface is most likely due to base metal oxides. If base metals are on the surface, they are also in the metal. This would mean that the 99.96% XRF reading is most likely in error, which wouldn't surprise me at all. At that high a gold reading, I have zero faith in XRF. If the purity were actually, say, 99.5% or maybe even 99.9%, there could be enough base metal contamination to cause some surface discoloration. It doesn't take much.

If the 10% sulfuric doesn't lighten it, try a little warm 15% nitric or 40% HCl and see what that does. If nothing lightens it, the color is probably throughout the metal and this would mean the gold purity is quite a bit lower than you think it is.

You might also abrade or scrape the surface and look for a color change.

It is often difficult to see the true color of shiny metals. Place a Kleenex or other tissue over both this shot and the shot whose color you're comparing it with. Put a drop or two of water on each one. Try to gently smooth out the wrinkles without tearing the Kleenex, so it conforms to the shot. Now you should be able to see the true colors. We used this test to compare the plating colors of various formulations of "color" gold plating solutions.

What do you mean by "assay" - fire assay?

Was the shotting water clean?

Chris Owen
- Nevada, Missouri, USA

July 18, 2015

A. Dear nathan,
While you are making grains, you pour a metal in clockwise direction and rotation of water in which you are pouring melted metal should be anti-clockwise. see the results about colour, and time to refine pure gold.
When you test the grain by XRF, it has a limitation which gives purity of coating surface. Better to do fire assay.

bhupesh mulik
cac admixtures - mumbai,india

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