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Q&As since 1989
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Gold Recovery for Dummies? p2
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"Recovering Precious Metals" by George E. Gee (2002)
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"Refining Precious Metal Wastes" by C. M. Hoke (1982)
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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
February 5, 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.
Thanks
James
- New Mexico, USA
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?
BONNIE STARRgold smelter - Dyer, Indiana
March 30, 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 [on eBay or Amazon]; 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 aqua regia. There are a couple of other leaches but they are far more dangerous than the one I described.
Jeff Massey- Decatur, Alabama
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
June 23, 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 lanecrap - Illinois usa
October 24, 2012
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 3, 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 eBay thing. Just want to see if I can do this.
What solution do I need?
Thanks
- Lancaster, New York, USA
February 14, 2013
A. Hi Rich. I don't know what you mean by "the eBay thing" ... buying gold recovery equipment [adv: that stuff on
eBay], buying gold-bearing scrap [adv: gold scrap on
eBay], selling scrap to eBay?
If you feel that you know enough to safely experiment, no one can stop you. But things that seem dirt simple often aren't really quite that simple :-)
When you are doing electroplating, you're not moving tiny bits of gold metal from the anode to the cathode (that's not possible), what you are doing is dissolving the gold into the solution as a gold salt, moving the gold ions in the salt from anode to cathode, then oxidizing the gold salt back to gold metal. So to create even the poorest gold plating deposit for subsequent refining requires that you use a solution which is capable of dissolving the gold as a salt and keeping it in solution. That is hard to do without a "hazardous solution", usually based on deadly cyanide -- it's not something you are going to do with table salt.
"Gold Refining"
by George Gajda"
on AbeBooks
or
eBay
or
Amazon
(affil links)
which explains what can be achieved by de-plating, and on which substrates. Strong sulfuric acid, S.G. 1.65, with some sort of cooling to make sure it doesn't go above 100 °F should work. But the gold does not plate out, rather it precipitates as a mud, probably requiring further refining to be saleable.
Luck & Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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 24, 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 you are 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 forever remain techo-babble, leaving you with 3 choices: to stop, to live very dangerously, or to commit yourself to studying & learning the subject. George Gajda's wonderful little book "Gold Refining" [adv: this book on
eBay ,
Amazon,
AbeBooks]
covers every aspect of the whole subject and is very understandable.
If you want to just try to scrape the gold off with an Exacto knife
[on
eBay or
Amazon] be 100% sure to never do it without wearing good, real, safety glasses [on
eBay or
Amazon]. Best.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 25, 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 14, 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 just jump from step 5 to step 16 in one leap :-)
Luck & Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 15, 2013
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 5, 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
December 21, 2013
Recovery of gold from cyanide solutions that have sodium chloride?
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.
- Bogota, Colombia
January 21, 2014
PGC electrowinning/recovery
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.
- Bogota, Colombia
January 21, 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.
Process Engineer - Malone, New York, USA
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 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 :-(
- Bogota colombia
A. Hello Daniel,
If you refer to the posting on this thread dated Jan 7, 2012 by C Wilford, it will give you step by step instructions.
process engineer - Malone, New York
Is potassium cyanide the best electroplating substance?
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 Moorebuyer - Austin, Houston, Texas
November 21, 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.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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 Woodsonbuyer - Austin, Houston, Texas [returning]
November 28, 2014
A. Hello again Jones.
silly :-) You seem to have forgotten your name between your two postings, while your IP address says that you're not even posting from the continent you claim you're on ... we hope your experiments with these highly toxic chemicals haven't turned you into a mad hatter already. We warned you they were dangerous! :-)
I think the next question/suggestion after haz-mat certification, and before you de-plate, and thereby lose track of the gold, is: "how will you measure the amount of gold on the spoiled computers". There's no point in even trying a recovery method until you can accurately track the gold -- without that you have no idea how much gold you're recovering vs. how much you're just pouring down the drain, and which steps it is most important to improve.
Be careful. Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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 an easy cheap flocculant to knock the gold out? And will I still have silver and other metals dropping out as well?
Thanks,
Kevin
Hobbyist/Recycler - Merritt Island
September 19, 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?
cac admixtures - Mumbai, India
October 18, 2015
Ed. note: Thanks Bhupesh, insightful question! Flocculants don't help settle dissolved salts, they only help settle precipitated solids.
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?
- Surabaya, Indonesia
October 30, 2015
A. Hi SAPI,
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.
CAC admixture - Mumbai, India
Hydrazine hydrate concentration for gold recovery
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.
- 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
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.
CAC admixtures - Mumbai, India
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
May 25, 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, don't add urea.
CAC admixtures - Mumbai, India
Q. What would be the easiest way to recover gold from concentrate and with WHAT chemicals?
TRACY NEUWERTH- mogale city, SOUTH ARICA
June 4, 2016
? Hi Tracy. Please pardon my ignorance and tell me exactly what "gold concentrate" is.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. Hi Tracy,
Gold concentrate may be gold dissolved solution.
Ferrous sulphate [on
eBay or
Amazon] is better chemical for reducing gold.
CAC admixtures - Mumbai, India
August 15, 2016
Immersion Gold on Gold Plating
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 ChaseHobbyist restorer - Baker City, Oregon, USA
June 16, 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.
- Benton, Arkansas, USA
June 20, 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
- Quebec, Quebec, Canada
July 6, 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
Hampshire, England
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.
Student - Manila, Philippines
July 30, 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 may be achievable. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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 4, 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
- spanaway, Washington USA
October 13, 2017
A. Hi, for palladium recovery dimethyl glyoxime (DMG) is used.
Thanks,
CAC admixtures - MUMBAI, Maharashtra, India
Q. Hi I have a scrap gold from computer components containing small amount of copper. If I were to put an electronical charge though this mixture in the same way as you would in copper plating is it possible to remove the copper without affecting the gold? Thanks.
Sid strong- London England
October 1, 2018
A. If I understand your situation correctly, the answer is no.
What is the source of the metal? What form is the metal in now? Powder? Bar? What? What is the approximate weight?
- Benton, Arkansas, USA
Q. Hi, my name is Charles. I have some metal alloy plates and will pass on a scratch test with 14 karat gold testing acid and metal detector too. Is this possible and how can the gold be extracted?
Charles Nelson- Tulare California usa
June 9, 2019
A. Hi Nelson. When you say "metal alloy plates" that have passed testing, it sounds like you are describing solid metal, not a plating. If you are confident enough in your testing to go further, I would take one of the plates to a scrap metal dealer who has a scrap sorter [on eBay or Amazon] X-ray fluorescence machine so they can tell you what you have. Because, unless you are highly experienced it is usually impractical to attempt to recover gold without knowing what you have -- there are several sequential steps in the process where you separate the wheat from the chaff and you'll have no idea at which steps you threw away how much of your gold as waste if you don't know what you started with. Good luck :-)
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2019
Q. How does one get the gold out of Aqua Regia?
Philip BadenhorstMining - Swakop, Erongo, Namibia
June 11, 2019
Recovering Gold and Palladium from test strips
Q. My name is Kevin, What to do with 1 Million gold, and 500k palladium test strips? I even have the solid gold and palladium full uncut sheets ... about 100 pounds in all. Should I take it to be processed? Or try this myself? I'm a laser engineer who designed the lasers to originally cut the strips, not a chemist. Thank you
Kevin Davis- Hazel Park, Michigan USA
March 11, 2020
A. If you actually have 100 pounds of pure gold and palladium, you have a substantial fortune.
Check with a reputable precious metal refiner. You can retire to the French Riviera.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
March 14, 2020
I have A Clear green so what am I not doing to get the gold from there
- Tucson AZ US
May 21, 2020
Q. I bought 5 lbs of smelted computer parts, smelted with borax [on eBay or Amazon] . If I repeat smelting with borax will it get any more pure? It now tests at less than 9%
mark gibson- calexico california
May 23, 2021
Q. We are working on e-waste recycling using aqua regia solution but because of lack of information we added more urea in it and also more smb. Now when we look at our solution after one day we found that a lot of smb is collected in the bottom. When we try to melt that in order to obtain gold precipitate from it, it is taking lot of time and upon heating a crystal starts to form. Is there any other way to separate smb and gold? Or any idea how we can get optimum benefit? We are school students.
Anikesh singh
- Kosamba Gujarat
June 4, 2021
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