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topic 33616p3

"Gold Recovery for Dummies?"



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A discussion started in 2005 but continuing through 2020

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



June 9, 2019

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 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" 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,

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



June 11, 2019 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. How does one get the gold out of Aqua Regia?

Philip Badenhorst
Mining - Swakop, Erongo, Namibia



Recovering Gold and Palladium from test strips

March 11, 2020

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 14, 2020

A. If you actually have 100 pounds of pure gold and paladium, you have a substantial fortune.

Check with a reputable precious metal refiner. You can retire to the French Riviera.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina

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