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topic 33616

"Gold Recovery for Dummies?"

A discussion started in 2005 & continuing through 2017


Q. Well Hello. I just stumbled across this forum as I was looking for information on Gold Scrap Recovery and thought it was as good a place as any to start. I have read the posts and have to say that I agree with the many warnings associated with the use of ANY chemical. With that said, I am an engineer working in the Semi Conductor industry and have worked with a myriad of chemicals including Nitride, Phosphorous, Hydrofluoric and Sulfuric acid and others. I am pretty well versed in the care and use of said chemicals and have access to a rather well furnished lab. I also have access to many old high-end computer components containing a relatively fair amount of gold. Not to mention a large amount of old jewelry and plate items.

Now that I have set the stage, I wish to ask of those "in the know" for a "Gold Recovery for Dummies" version.

Also, would it be feasible to attempt recovery from ceramics and pottery that contain GOLD embellishments?

Any help would be appreciated. Thank you in advance for your time. Regards

Still Searching.

Cory G [last name deleted for privacy by Editor]
Engineer/Hobbyist - Caldwell, Idaho


A. Hi, Cory. Info on the internet is, as you know, a food fight rather than a sit-down dinner--but letters 771b and 18889 are a good start. Good luck.

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


A. You can leach it off with a 5% solution of sodium or potassium cyanide (REALLY TOXIC STUFF!), a dash of 35% Hydrogen Peroxide [linked by editor to product info at Amazon] makes it work faster. Then you can electroplate out the gold.the solution is reusable just add a little more cyanide if it quits working. Another method is digest the metal in 50% nitric acid this will leave pieces of gold leaf behind which you can filter out. Gets kinda expensive unless you have a cheap source of HNO3. As far as the gold on pottery goes you would have to process a heck of a lot since it's only a few millionths of an inch thick. You can kill the cyanide with calcium hypochlorite for disposal. I once got about 3 oz of gold off mil spec connector pins but I had to process about 27 pounds of them. Good luck and be very careful with the cyanide.

Jan S [last name deleted for privacy by Editor]
- Dallas, Texas

November 19, 2009

A. Well Cory I am an Engineer for a large gold mine. You have a good idea here... The Chemistry problems are real, as you know. And I'm sure you know that I WOULD NOT LEACH AT MY HOUSE or try to make any CN product without being in a proper lab or a place designed for it. Always keep CN solutions at a pH of 10.5, realize that if your pH hits 9.3 your gassing of half of the CN in your solution...BAD NEWS. At 10.5 your only losing <1%. If the pH gets over 11 the solution has a hard time picking up gold.

With that said you can get gold out of anything and they are right NaCN works great for a lot of "host" materials, but do NOT use it where acids or S's are present. Also realize that in our leach pads we use a basic rule: 150 micrograms takes 45 days in a leach pad with cyanide consecration of .2 lbs/ton and an application rate of .003 GPM/ft^2 (you will be much high on both of these numbers). The big problem is cyanide the problem is you will have to make it; no one will sell it to you. You're a chemist and probably can think of ways to make it. (to help make sure no one gets hurt I'm going to let you do some of the Engineering work) But one way is NaCl, C (flower will work) and N2(g) from a welding store, e's are involved, you get the picture.

When extracting make sure your CN Solution has flow, the amount of gold is directly linked to CN concentration, the overall solution can (when ratios are right) hold 500 oz gold / ton of solution.
Remember pH pH pH

You can skip any carbon loading for concentration and go straight to electrolysis. Start with 6V don't use a Cu cathode, use gold, this will keep you from having to refine with acids and some other headaches.
Remember pH and do NOT pour the CN solution down the sink. If you're going to pour make sure the CN is totally killed with something like CaO, Baking soda
Anyway stay safe, good luck, Gold may hit $1500 + in 2010. A lot of the big companies are planning on it.
Anyway there are a lot of in's and out with gold extraction, have fun.

B Mat Chap
- Elko, Nevada

Recovering Precious Metals


Q. I am currently researching on methods which I can use to recover gold from electronic components, mainly IC chips. I have also researched that using aqua regia to dissolve the gold might work but how would I then precipitate out the gold? I would also know the standard ratio of hydrochloric acid to nitric acid to use in aqua regia. Thank you.

Hashvin P [last name deleted for privacy by Editor]
student - Singapore


Q. I want to know the gold recovery through eco-friendly from the gold ornamental working places. This question arises because the gold loss cost will be the part of product cost. Compared to the other metals, gold is the costliest metal which is used as an ornament.
Is there any easiest method for gold recovery from various dusts without using acids and chemicals?


Employee - Tamil Nadu, India


A. It is becoming My experience that the Most Profitable avenue for you would be to split all your "scrap" into manageable "Lots" & sell it on ebay to others! I am so far just buying and trying to Recover & Refine:
Computer Scrap ~ one, two & three pound lots.
Jewelry ~ 15 to 100 gram lots.
Allow others to "enjoy" the illusion of easy money & get paid for the most part top $$$.

Richard Hardeman
- BHC, Arizona

February 12, 2008

Q. Hi, I'm really interested to know how to recover gold from the computers motherboards, IC's, microprocessors and all that is related with electronic circuit boards. Any ideas will be appreciated. Thanks in advance.

Jorge Fajardo
- Bogota, Colombia

February 13, 2008

! Folks: E-waste is a huge worldwide environmental problem, and two pieces of the problem are:
- Doing the process in uncontrolled environments whereby the toxins become spread everywhere.
- "Cherry picking" the gold, which leaves the remainder of the waste of insufficient value for anyone to ever attempt to collect and recycle.

Mankind has advanced beyond killing a whale for a barrel of sperm oil or an elephant for a few pounds of ivory and leaving the rest to rot. Every environmental organization in the world is begging us not to follow the same path with e-waste, trying to recover a smidgeon of gold, at the cost of leaving acres of highly toxic electronic components polluting the earth. Please view a couple of the dozens of videos on "ewaste" on YouTube before proceeding, and do your best to recycle responsibly.

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

Recovery And Refining Of Precious Metals

March 11, 2008

Q. HI,



March 13, 2008

A. Please realize that these items were not "dipped" in gold in the fashion of chocolate covered strawberries, Andy. They were nickel plated for brightness and then electroplated with a very very thin layer of gold, probably less than 20 millionths of an inch thick. Look at a feeler gauge 2 thousandths of an inch thick, if you can find one that thin, and recognize that the gold is less than 1/100 of that thickness. You will certainly not recover it as a "shell" of any sort. Sorry.

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

April 28, 2008

Q. I want to find gold; I know it is in computer boards and other electronics. What else has it in it. Maybe glucose test strips? Do they contain gold also?

Lonnie Keith
curious, seller - Meigs, Georgia

Refining Precious Metal Wastes

September 30, 2008

Q. I have old computer parts that I am scrapping. I have been tearing them down and taking them to recyclers who say that they send them out to other plants because of EPA regulations. I am having trouble believing them and also making any money. Metal is way down and I have a large amount of plastic to get rid of. Anybody know the rules about chemically removing the gold and platinum?

Steve Pruitt
computer recycler - St Regis, Montana

October 4, 2008

Q. I would like to ask this question: Are the contacts in the mylar strips on print cartridges gold plated?

James Mills
- Big Spring, Texas


A. Hi, James. At a small risk of oversimplification, yes, if a low voltage electrical contact is the color of gold, it is gold plated.


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

April 7, 2009

Q. I was attempting to electroplate out the copper and nickel from circuit board connectors. I am using a vinegar and salt mix for my electrolyte. the connectors are used as the anode. A sheet of copper approx. 6" x 3" is my cathode.
Power is a 12 V 2 A transformer.

My theory was that the Acetic acid with added sodium chloride would dissolve the copper and nickel allowing it to plate onto the copper sheet while the gold would sink to the bottom.

The first attempt seemed to follow this theory; however, I did not notice any change in the thickness of my cathode. I figured this was due to how little copper plated out prior to the gold flaking off.

Repeating the process with the already saturated mix resulted in the mix taking on more of a milky white appearance. I am guessing this batch must have had a different metal in it somewhere but I am unsure what metal would cause such a reaction. the solution also seems to have particles of corroded copper (dark green) floating on it.

my questions are: 1. any theories on what would cause this? 2. why am I still not seeing the cathode getting thicker after almost 4 weeks of total run time?

Joshua Wert
hobbyist - crescent city, California

November 19, 2009

! Dear readers! If you overheard doctors discussing an appendectomy, you would not try one based on what you heard :-)

Please remember that internet forums are a "one-room schoolhouse" where you will read snippets on subjects that may be dangerous to dabble in if you are not trained in that field. The idea of anyone who is not a trained professional chemist with haz-mat certification trying to make cyanide is frightening.

CaO or baking soda does NOT destroy cyanide; cyanide treatment requires alkaline chlorination.


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

October 28, 2010

Q. I have a bunch of unopened bottles of precious metal glazes for ceramics.
Each says it has a net weight of 1 gram of gold or platinum.
Is there a way to recover the metal from these liquids?

Cory Christensen
hobbyist - SLC, Utah, USA

October 19, 2011

Q. Sir, I am doing the scrap gold. I got a problem in gold recovery that is, actually I am using the method of collecting the gold coated material and adding the nitric acid and giving the heat. After boiling the acid, the gold layer appearing the top, collecting the gold layer, when I try to heat that gold it becomes nothing. All coated material gone. Any suggestion on this? One problem is nickel; a extract in this method I believe that nickel combines with gold; this my case.

Mulka Kalidas
gold worker - Hyderabad, India

October 30, 2011

Q. Metal recovery from Philosophers Stone after conversion. I have been working on this process for sometime, I am not 100% certain of the yield as yet as the conversion process is a little messy - basically what is left after extraction is a fine white powder a little like talc then this is converted to metal form, it maybe more beneficial to keep in the white powder form for the properties it contains, however once converted back precious metals show and this has the higher market value at this point. Is it better to have someone else extract the metal elements from this powder rather than if I do this myself, are there any decent metal recovery company's I could send this to in Australia.

Andrew Ruselle
Opportunist - Australia

January 7, 2012


For every ounce of scrap gold you are going to refine you will need a capacity of 300 milliliter container for the aqua regia solution.

1. Place impure gold to be dissolved into a glass or plastic container.

2a. Aqua regia - Mix one part nitric acid to 3 parts hydrochloric acid. OR
2b. To the container, add 30 milliliter of nitric acid for every ounce of metal.

To the container, add 120 ml of hydrochloric or muriatic acid for every ounce of metal in the container.

3. Allow impure gold to dissolve for an hour to overnight for complete dissolution.

4. Once all gold is dissolved, filter out any particles out of the acid solution containing the liquified gold into another glass container using a fine stainless strainer. The remaining particles should not be discarded as these may contain other precious metals!

5. The acid containing the dissolved gold will be an amber to emerald green color depending on the purity of the gold and should be clear (not murky or cloudy). If the acid solution containing the dissolved gold is murky, it may contain particles and should be re-filtered with a finer grade paper filter.

6. Slowly, add the water/urea (urine ) to the acid solution containing the dissolved gold. The acid solution containing the dissolved gold will foam with the addition of the water/urea (urine). Do not add the water/urea (urine) so quickly that the acid foams out of its container. When the acid solution containing the dissolved gold stops reacting to the addition of water/urea (urine), stop adding the water/urea (urine). You've just raised the pH of the acid from 0.1 To 1.0, killing the nitric acid but not the hydrochloric.

7. Add precipitant ( sodium bisulfite ) slowly in minute amounts to the acid solution containing the dissolved gold, immediately the acid solution containing the dissolved gold will change to a muddy brown appearance as brown particles of gold form in the solution. Occasionally agitate the solution with a glass stir rod, as the brown particles continue to form they will sink to the bottom of the container, this brown "mud" is, despite its appearance, pure gold.

8. Allow precipitant ( sodium bisulfite ) to fully draw out all the gold out of the solution, test for gold in the remaining solution, if it tests positive for gold, you may have to add more precipitant ( sodium bisulfite ).

9. To test the solution for remaining gold, first immerse the end of the stirring rod in the acid. Remove it and touch that end to a paper towel to make a wet spot. Put a drop of gold detection liquid on the wet spot on the paper towel. If any gold is still dissolved in the acid, the wet spot will turn a purple-black or a purple-brown. If you see this color change then give the precipitant more time to work and/or add more precipitant.

10. Now all the gold should be drawn out of the solution and the acid should now be a clear amber color with a brown mud settled at the bottom.

11. Using a fine paper filter, pour off the acid into another container allowing the mud to stay in the filter. The mud is pure gold.

12. When all the acid is poured off, return the mud to a container for rinsing, add tap water to the mud. Stir and let the mud settle. Using a fine paper filter, pour off the tap water into the container with the acid. Do not pour off any particles of brown. Repeat this rinsing 3-4 times or more.

13. After completing the final tap water rinse, rinse once again with aqua ammonia ( %10 ammonia to %90 distilled water ) white vapors will appear. The aqua ammonia cleans impurities from the gold mud while, at the same time, it neutralizes any acid still clinging to the gold mud.

14. While in the fine paper filter, give the mud on last rinse, this time with distilled water until mud and filter is clean.

15. Take filter with clean gold mud and gently squeeze of any excess water and place filer with mud into crucible for melting.

16. Once melted, the gold will again take on the appearance of metal. If you've followed the instructions carefully and used filters, the gold will be 999.5 % Pure with virtually no losses.

17. Platinum- If you had platinum in your gold, it will not dissolve, to any appreciable degree, in the room temperature aqua regia. It will be left behind when you pour off the aqua regia, prior to precipitation. To insure high purity of the platinum, you will need to re-refine this material. Put this material in a fresh aqua regia bath. This time, however, heat the acid to simmering. Continue heating until all the platinum is dissolved (that may take 1-2 hours). When completely dissolved at 1 ounce of ammonium chloride for every ounce of dissolved platinum. The platinum will precipitate as a red mud. If you want to leave the iridium in the platinum, then wait for it to precipitate before recovering the platinum. Iridium will precipitate as a blue-black mud after the platinum precipitates. Platinum group metals will also show up on the stannous chloride test. Platinum turns red, palladium Palladium turns orange and iridium turn blue-black.


January 16, 2012

A. Philosophers stone? Alchemy? When using nitric acid to remove base metals in gold recovery it is very easy to misplace your gold. On electronics that use gold for shielding (such as RF shielding) the gold can be very thin and instead of coming off in foils will separate into finely divided particles and will get lost in trash. Another cause for missing gold recovered this way is bad work habits. Dirty glass that has been cross contaminated will hold chemicals that can't be seen. Did you use the glassware for any solution that contained a HCl acid solution? If so, remember that you can't rinse acids from materials. If you use a container for a HCl solution and then rinse well, and then use it for a nitric acid solution a weak aqua regia will form and dissolve values. A small amount of HCl will make quite a bit of AR solution. As far as the philosophers stone, the only one I can think of is the one in the Harry Potter stories. Values that have been precipitated have distinct colors and as far as white powder goes metal salts can be white if crushed finely enough. If you would like some help, put the witchcraft aside and let me know what you did to get what you have and I will try to give some advise on what it is and what can be done with it.

Jeff Massey
- Decatur, Alabama, USA

February 5, 2012

Q. What chemicals are used to decay gold from ore so that you can extract 90-100%? I would like to extract 100% of gold from its ore -- what chemical can be used to insure all the gold within an ore is extracted?

Abdulkarim a
- Cottbus, Germany

March 12, 2012

Q. My first couple of batches with AR (aqua regia) worked out great and got really clean gold out of it after melting. I tried sub zero the last few times and it has left me a mess! I know there is gold in it I should have about a half oz somewhere in my buckets. After dropping the gold with smb it turns brown and eventually developed but unlike the first few batches with nitric acid it is reacting like pd during the wash and is nearly impossible to pour off. After boiling in distilled water to help bond it together through out the many washes it is turning black and has edges on it and melts to a dark silver lead color. What is going on? I have read that too much smb will drop lead and other metals with the gold but it is brown at first and is super buoyant. Is this large brown sponge good? Should I just wait it out till it settles and not boil it? I have distilled some of this brown sponge but by the time it dries it is not brown anymore! I am very confused and frustrated. Also with the nitric I didn't get the return I was expecting but at least I got some gold out of it! Will the aluminum foil drop the gold and all if I end up having to start completely over? I tried another batch of AR with this black substance powder and still no luck! Is it the sub zero or just a mistake on my part? Please if anyone can help! I thought it would be easy after the first couple batches but now have way too much money invested to not be getting a return.

James Snipes
- New Mexico, USA

March 30, 2012

Q. I have removed gold connectors and other gold pieces. I need to know the simplest way to smelt it and where I can purchase the products. Can you please help me?

gold smelter - Dyer, Indiana

June 3, 2012

A. Chemical extraction of precious metals from ore is a very long and tedious process. First, the ore has to be roasted to a red hot temperature and held there for 20-30 minutes; this reduces the sulfides to sulfur dioxide and the organic carbons to carbon dioxide. Next, you need to mill the material to about 200 mesh. The first chemical leach will need to be ferric chloride; this will remove iron; heating the material speeds this process up. After the solution turns black, decant and rinse well several times with water. Next, add diluted sulfuric acid and stir; heating the material speeds this process; this removes any iron oxides left from the ferric chloride wash. Rinse with water with several cycles. Now you are left with a good material fit for leaching with AR. There are a couple of other leaches but they are far more dangerous than the one I described.

Jeff Massey
- Decatur, Alabama

June 23, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Certain easy steps to refine gold from old cpu using Nitric acid or AR?

Hello. I started my refining process since two weeks before, I am stuck up in the nitric acid process. I am able to see the golden foils in the bottom of the glass jar along with other metals, which I am not able to separate. Kindly help in this step.

Syed Nooruddin
- Bangalore, Karnataka, INDIA

October 24, 2012

Q. Hi I recycle computers. I want to know is there a way to get gold without dangerous chemicals? If I could learn without danger to my life?

larry lane
crap - Illinois usa

February 3, 2013

Q. I am an avid treasure hunter and I find lots of gold plated, gold filled, and silver plated items yearly. I know they do not have a tremendous amount of precious metal on these items yet if I could recover it inexpensively it would eventually add up. I also have several pounds of gold plated electronic scrap I would like to recover the gold from. So my question is simply what is the most cost effective, safest and simplest method of doing this. I have an extensive background in both OSHA and EPA regs. and have spent many hours in chemical environments. Is this a viable idea / hobby that will allow me to make a few bucks without investing a fortune with no hopes of a return?

Ralph Waldrop
- Seymour, Tennessee, USA

February 14, 2013

Q. I want to use the electrolysis method -- reverse plating!!
I have gold covered items mainly leaf over paper. I also have computer parts.
I would just like to be able to actually use a glass fish bowl type - 4 gallon capacity - what type solution would help the transfer of the gold from the host to the anode?
I would prefer no hazardous solution - I also have already made arrangements for a scrap yard to recycle left over scrap materials.
This is a hobby type endeavor. I don't want to do the e-bay thing. Just want to see if I can do this.
What solution do I need?

Rich Orbza
- Lancaster, New York, USA

June 24, 2013

Q. Hi. I am trying to get gold from cell phones. There is lots there and I am grinding the gold off, then using sulfuric acid. It is getting most of the stuff to dissolve the silica but the copper is still there? I have seen your posts on different ways to extract gold and lots of techno-babble. I am dyslexic but not dumb. Need to know safe and productive way to retrieve gold. There are lots of phones out there and money to be made. Any help would be good, thank you.

Logan Yeates
- Mission, BC, Canada

June 25, 2013

A. Hi Logan. Do you know the thickness of the gold plating, so you have some idea of how much gold is there? You'll never know whether your process is efficient or wasteful and just pouring most of the gold down the drain until you start with that. Good luck.

This page includes the step-by-step instruction you seek (for example, the 17 steps generously offered by C. Wilford), please don't dismiss them as "techno-babble". People have told you there is no safe way for someone with no chemistry knowledge and training to dabble around in complex chemical recovery operations involving cyanide and aqua regia, so there is no "safe and productive way". Sorry.

Complex chemistry can't be made simple. If you don't learn the relevant chemistry it will remain techo-babble. You really have but 3 choices: stop, live dangerously, or commit yourself to studying & learning the subject. Best.


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

October 14, 2013

Q. I have a question. How to get the gold out of the liquid after using Muriatic acid and Peroxide? It is green from copper. OK. But it has a lot of gold in that liquid.

L. Kiss
- Tucson, Arizona

October 15, 2013

A. Hi L. Please try to phrase your question in terms of the step-by-step instructions that C. Wilford posted. You can ask for clarification of a step that you don't fully understand, but you can't reasonably ask how to skip steps 6 through 15, and jump from step 5 to step 16 in one leap :-)

Luck & Regards,

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

December 5, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi friends!
There is no e-waste recycling company in our country. I have the question of how to recover gold from discarded cell phones. I need to learn a complete process to recover gold and other precious metal from them. Please somebody help me.

Himel Jahan
- Dhaka, Dk, Bangladesh

December 21, 2013

Q. My uncle is also getting into this. Anybody have ideas to extract gold from rocks and circuit boards? Is there any way to do this like smelting? Any chemicals or etc.? Please post if so.

Cory Mill
- Belton, North Carolina, US

Recovery of gold from cyanide solutions that have sodium chloride?

January 21, 2014

Q. Good afternoon. I wonder if anyone knows how to recover gold from cyanide solutions when the solution containing gold has also added sodium chloride?
What happened is, trying to recover gold from PGC salt (potassium cyanide and gold), which was dissolved in water and carried electrolysis but by mistake addition of sodium chloride which changed the color of the solution to a pale yellow, then added potassium cyanide to improve conductivity but did not recover anything in electrolysis, and nothing that I could form compounds with sodium chloride. I think that when you add the sodium chloride of the gold PGC AuCl4 step.

Mauricio Bernal
- Bogota, Colombia

PGC electrowinning/recovery

January 21, 2014

Q. Good afternoon ,

We tested the effectiveness of the PGC recovery through the electrowinning process but we are having complications; we used our existing equipment to recover 446.7 grams of PGC , which was dissolved in 35.4 liters of water and processed for 4 hours. Seeing no apparent results, we added 150 g of sodium chloride dissolved in 800 milliliters of water with the idea of breaking the link of cyanide -- this process took 3 hours, the color of the solution changed to yellow and the cathodes changed their color to copper. Because of this, we assume that the brass was being attacked; we added KCN 705 grams dissolved in 1.7 liters of water and left for 7 hours, but so far there is only a small gold layer on the cathode.

We do not know if they could have made another compound which is not compatible with the recovery process; we think that may have formed AuCl4 gold tetrachloride, sodium cyanide, PGC in solution, or sodium hydroxide .

The main question is: which compound is formed by adding sodium chloride to dissolved PGC? The result of this reaction? And how to recover the gold contained in it?

We appreciate your kind cooperation.

Daniel Barrera
- Bogota, Colombia

January 23, 2014

A. Hello Daniel,
Your first run with PGC and water would not work at all because there are not enough "throwing" salts in the PGC to plate with. I don't know what, if anything, sodium chloride would do to hamper your efforts on the second run. What I do know is that you will never get your money's worth trying to electrowin gold. You will never plate all the gold out of solution because once the concentration of gold drops to a certain level, the current efficiency suffers dramatically. This matter is worse if you don't adjust the current on the rectifier accordingly as you go along. when you had PGC in salt form you could have easily sold it back to the supplier, or a local shop that plates gold. This is easy to do especially if the PGC is still sealed in its container. Now you have choices to make that will cost you more money because you will have to have it refined. You can drop the gold out of solution with aqua regia, or run it through a resin column designed for gold recovery or use a gold bug. Sorry, I cannot explain precipitation with aqua regia because it should be left to professionals that have done it before, and have the proper safety equipment and facility to do it in.

Mark Baker
Process Engineer - Malone, New York, USA

February 7, 2014

Q. Thanks for your answer, we already made the aqua regia procedure,IF SOMEONE WANTS TO DO THIS PLEASE BE CAREFUL: CIANHIDRIC ACID [hydrogen cyanide] IS PRODUCED IS EXTREMELY HARMFUL.

200 ml were taken, by titrating the amount of free cyanide was determined. Based on this a few drops of hydrogen peroxide was added to remove free cyanide, thereafter rechecked and with only a single drop of silver nitrate liquid changed color. Then added 100 ml of aqua regia, let it warm up until boiled over, then we add urea to adjust the hp, and then 5 grams of sodium metabisulphite dissolved in 20 ml of water to precipitate the gold, allowed to decant. Black colored precipitate appeared which was filtered and melted but did not show gold, according to the concentration should be 1.6 grams.

We are still having problems :-(

Daniel Barrera [returning]
- Bogota colombia

February 11, 2014

A. Hello Daniel,
If you refer to the letter on this thread dated Jan 7, 2012 by C Wilford, it will give you step by step instructions.

Mark Baker
process engineer - Malone, New York

Is potassium cyanide the best electroplating substance?

November 21, 2014

Q. Hello. I am getting into the electroplating business. I actually have tons of computers and someone told me in order to get off the gold from within the computer components, I could get potassium cyanide. But from my findings and comments on this site, it seems expensive. So I want to know if that is the best way to get off the gold. Any other suggestions? I will like to get answers or someone who can sell potassium cyanide cheap.

Jones Moore
buyer - Austin, Houston, Texas

November 2014

A. Hi Jones. Potassium cyanide is one of the fastest acting and most potent poisons known. Please make sure you have enough chemical knowledge, and a secure and well-equipped enough industrial facility to deal with it safely. The grass is always greener on the other side of the fence, and the path to riches always seems to involve the fields we know little about. Good luck, but I wouldn't buy potassium cyanide until I completed a haz-mat training course.


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

November 28, 2014

Q. I got quality potassium cyanide from an online store. They gave me instructions on how to handle potassium cyanide. I am still undergoing an intense training on how me and my team can use the product on the vast room of spoiled computers I have. Thanks again. Any other suggestions will really help me on how to handle it and how to do my electroplating.

Jones Woodson
- Austin, Houston, Texas

November 2014

A. Hi again Jones.

I think the first question/suggestion after haz-mat certification is how will you measure the amount of gold on the spoiled computers. There's no point in trying a recovery method until you know how to accurately track the gold, because you'll have no idea how efficiently you are operating and where the gold losses are taking place.

thumbs up sign You seem to have forgotten your name, and your IP address shows that you're not posting from the continent you say ... we told you cyanide was dangerous! Either that or you're not very proud of the recovery operation you're running :-(

Be careful. Regards,

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

Gold in suspension

September 19, 2015

Q. Hello, I've acquired a property with a vast amount of computer components. The components were originally purchased at a NASA auction, so they have a high amount of precious metals. I've attempted selling, but since the parts are antiquated there is not much interest. So I've been attempting to recover some of the precious metals.

I've been using a mix of 50/50 32% hydrochloric acid and 3% hydrogen peroxide. I've been extracting excess copper with electro-less crystallization with stainless steel.

After extraction, I'm having a lot of gold, and I'm assuming other precious metals in suspension. After washing, I've been using a surfactant and still have inadequate precipitation. Is there a easy cheap flocculant to knock the gold out? And will I still have silver and other metals dropping out as well?


Kevin Curl
Hobbyist/Recycler - Merritt Island

October 18, 2015

A. Hi kevin ,
basically which flocculant you use in gold deposition?
I can definitely solve your problem only if you share which process you applied?
Is it flocculation process or precipitation of gold?

bhupesh mulik
cac admixtures - mumbai,india

October 25, 2015

Q. Hello,

I have been doing aqua regia, but the gold that came out is not pure 99%, it is always 97-98%. How do I increase the purity?

Sapi Meu
- Surabaya, Indonesia

October 30, 2015

You are doing something wrong in your process; after aqua regia process you should get minimum 99.1 to 99.5% gold purity as per my experience.

bhupesh mulik
CAC admixture - Mumbai, india

Hydrazine hydrate concentration for gold recovery

May 3, 2016

Q. I have a job of gold recovery from cyanide solution, waste scrap of jewellery, etc. I have a problem with this.
When I complete aqua regia, I add a little amount urea. After that I add hyrazine hydrate solution 80%. I dilute it with 100 ml hydrazine and 400 ma water. After addition of it, precipitation occurs, but gold that precipitates is in the form of dust, not in a spongey big ball.
What the problem is I can't understand.
And when I filter it with filter paper some amount of gold dust filters out at bottom of flask. So please help me what is the problem I'm facing.

Ritesh Parmar
- rajkot, India

May 3, 2016

A. I've been refining for 50 years and I have never worried about what the precipitated gold looked like. As long as I got it all out (as confirmed by testing the solution with stannous chloride), I wasn't concerned about the appearance. It always looks a little bit different, even if you split the solution and precipitate the 2 halves separately.

Chris Owen
- Nevada, Missouri, USA

August 15, 2016

A. Dear sir,
I had gone through your problem; while forming nuggets, your water temp should be low. Maybe your water quantity is low, so you're pouring hot melted metal increases the water temp.
And rotate your water in clockwise direction and pour your melted metal in anti-clockwise direction.

bhupesh mulik
CAC admixtures - Mumbai,india

May 25, 2016

Q. My question is about gold recovery. I am facing a problem during its final stage. When I make aqua regia it becomes muddy. After that I filter it with paper. Then also it becomes muddy. Now I add urea and hydrazine. So gold becomes precipitated. But when I filter the solution precipitated gold also filters out. I don't know what is the problem. Please help to solve it.

Ritesh Parmar
- rajkot, India

August 15, 2016

A. Hi, Ritesh Kumar
I can solve your problem. As per my past experience, you are recovering gold from either polish or carpet burned dust. This problem will not occur in filing dust.
Main root cause is addition of urea; don't add urea and check. Urea lowers the acidic pH. Hydrazine also is a base pH.
So lower concentration of gold, do't add urea.

bhupesh mulik
CAC admixtures - Mumbai,india

June 4, 2016

Q. What would be the easiest way to recover gold from concentrate and with WHAT chemicals?

- mogale city, SOUTH ARICA

June 2016

? Hi Tracy. Please pardon my ignorance and tell me exactly what "gold concentrate" is.


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

August 15, 2016

A. Hi Tracy,
Gold concentrate may be gold dissolved solution.
Ferrous sulphate is better chemical for reducing gold.

bhupesh mulik
CAC admixtures - Mumbai,india

Immersion Gold on Gold Plating

June 16, 2017

Q. In immersion plating with multiple different ions competing with gold ions by first extracting the ions above gold on the electromotive scale with say lead. Then plating out the gold ions using gold plated metal or pure gold strips? If it will work would it just plate until the surface is covered or would it continue to plate until it exhausts all the gold ions in solution.

Chuck Chase
Hobbyist restorer - Baker City, Oregon, USA

June 2017

A. Hi Chuck. I don't understand your question about competition and extraction with lead, but no, you will not get any immersion plating onto gold strips at all because there is no electromotive-force battery to supply the electrons necessary to reduce gold ions to gold metal. Please start by describing what you are trying to do. Thanks.


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

June 20, 2017

A. Assuming the series is written so the more reactive metals (Al, Mg, etc) are at the top of the list (some lists are reversed), any metal that will drop out the metals between gold and the metal used will also drop out the gold at the same time.

Your best bet is to use copper, which is only slightly above gold on the scale. It will drop out gold and anything below it (Ag, Pd, Hg, etc.) but will not drop out anything above copper.

The general rule is: a metal will drop out (cement) all metals below it. However, the metal used must be able to dissolve in the particular solution that is used. For example, it is quite common to use copper metal to drop silver out of a nitrate solution. For each 3.4 grams of silver that is dropped out, 1 gram of copper will dissolve into the solution.

Chris Owen
- Benton, Arkansas, USA

July 6, 2017

Q. Hi,

Is it possible to deposit a selected metal at the cathode from a sludge containing Au, Ag, Cu, Fe? Knowing that the cathode and anode are made of graphite.

As an example: If I solely want to plate the cathode with gold (E0 Au+/Au = 1.69V) in order to recover it, will the application of a constant overpotential of -0.2V work?
assuming that E0 of Ag+/Ag, Cu+/Cu, Fe2+/Fe and Fe3+/Fe are 0.79, 0.34, -0.44, -0.04V), It seems to me that only gold will be reduced hence separated. Am I right?

Thank you.

Pall Assim
- Quebec, Quebec, Canada

July 8, 2017

A. Hi Pall
You do not say how you propose to get your sludge into solution but assuming that you do it should be possible to separate the metals electrolytically provided there are no complexing agents present

The problem is to control the overvoltage and to do this requires a potentiostat that is both expensive and requires some skill,

I would suggest that the most practical course would be to sell the sludge to an experienced recovery company.

geoff smith
Geoff Smith

July 30, 2017

Q. I am processing gold ore using NaCN or sodium cyanide, but this certain gold ore is really giving me a big problem. During processing the gold-copper ore it eats or consumes too much cyanide because of the high copper content. At the end of the process I've lost; I expend more money than I recover due to high cyanide consumption.

I read some article about using H2SO4; and also know as sulfuric acid can help to solve my problem.
I try to soak the gold-copper ore with the sulfuric acid to dissolve the copper.
But still not working well.

I also read a certain procedure using flotation but I actually can't understand it due to lack of education, and lack of chemicals and equipments.

Can anyone help me and can teach me regarding this matter.

Jason Lee
Student - Manila, Philippines

July 2017

A. Hi Jason. I can't help you with an improved process, but I can tell you that if you don't know what you have, no one can suggest whether any process will be economically viable. Has anyone assayed this ore to give you an idea how much copper, how much gold, and how much other stuff is in it? Without that I doubt that you can get anywhere even with education, chemicals, and equipment because there will always be ores with too low a gold content for practical processing; whereas, possibly, viable copper recovery is achievable. Good luck.


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

October 4, 2017

Q. How do I check acid solution for gold? Had a friend doing gold reclaiming in my garage, he took off, left me with a container, so I need to check it: it's green, dark green (was told darker the better). Help please.

daniel barnum
- millington, Michigan usa

October 13, 2017

Q. I have some (rocks) ground to dust. I would like to refine the (gold/silver/palladium/Pt). I have used Ar. ^Aqua Regia I would like to use Nitric acid and Al to reduce the Pd.

Can you help me?
Thank you

Reginald Brook
- spanaway, Washington USA

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