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topic 33616, p2

"Gold Recovery for Dummies?"



1       2


A discussion started in 2005 but continuing through 2018

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, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
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
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.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
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, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
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?

Thanks,
Kevin

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

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.

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?

TRACY NEUWERTH
- mogale city, SOUTH ARICA


June 2016

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

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
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.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
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

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
Hampshire, England



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.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
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


January 30, 2018

A. Hi, for palladium recovery dimethyl glyoxime (DMG) is used.
Thanks,

Bhupesh Mulik
CAC admixtures - MUMBAI,maharashtra,india



October 1, 2018

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 9, 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?

Chris Owen
- Benton, Arkansas, USA



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