Best way to process this

Hi,
I have some Milspec space application gold plated housings. . Some are large (8"x11") and complicated (~2" high and cavities on both sides), lots of walls, holes, cutouts etc.

I am planing on using a sulfuric cell but looking for other ideas or suggestions.

How deep can the sulfuric cell be? Because of the size how large a power supply would it require?

There is no rush so if there is another less intensive static process I would do that- Iodine?

Will this deplate evenly with all the different machined areas? How long would something like this take to deplate?

Would the cell generate a lot of heat? If so, can the bottom of the cell be connected (like a drain) to another container- the acid, along with the gold, can drain into it, the gold settle out, the acid cooled and returned to the cell constantly to reduce the heat and also the cell would not need to be disturbed for cleanout.

Please let me know whatever you are thinking

Thanks
GSH

i would chop that up with a band saw.

if you don't have one, try your local high school. they will chop it up for free

You want to use the least amount of sulfuric as possible with a cell. That acid scares me. And yes it will heat up depending on how big the volume is, the amp draw, how long the part is stripping, etc. all your answers are covered in the search box. Chopping it up would be the best way to deal with. But I would check that base metal isn't something like Berillium copper which makes some very toxic dust when cut.

Ebay would probably bring in the most money.
They buy everything for far more than it's worth.
You just want to estimate the worth for your reserve.

Jim

if it is a mil spec from a space project, copper would be to heavy, i say its 6061 t6 aircraft alloy. or something like it.

6061-T6 aluminum is commonly used in aircraft construction. Although primarily used in private rather than commercial aircraft, its strength-to-weight ratio is very high, making it ideal for large parts that need to be very light, such as the plane’s fuselage and wings. This light weight also made 6061-T6 aluminum the best choice for the famous gold-anodized plaques that were mounted on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft.

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http://www.sapagroup.com/en/na/profiles/6061-t6-aluminum-properties/

It looks like aluminum base metal. If it is and the gold is plated, there has to be a copper layer first before the gold is plated.
A quick wash in nitric acid dissolves the copper but leaves the aluminum and gold unaffected.
After the piece has been washed in nitric and the gold foils are loose you was the aluminum in water, then it's a simple matter to collect the gold foils from the wash water and the nitric.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177&start=20#p194541

Göran

g_axelsson said:

It looks like aluminum base metal. If it is and the gold is plated, there has to be a copper layer first before the gold is plated.
A quick wash in nitric acid dissolves the copper but leaves the aluminum and gold unaffected.
After the piece has been washed in nitric and the gold foils are loose you was the aluminum in water, then it's a simple matter to collect the gold foils from the wash water and the nitric.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177&start=20#p194541

Göran

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i would like to suggest that the title in linked post be fixed, there is no searching that spelling (sorry)

Once, at a University where I was on Staff, we acquired some Ballistic Missile logic units that were encased in Beryllium. They were very similar to what was shown in the image. The Gold plating was to prevent oxidation of the Beryllium, which is a severe health hazard. The reason Beryllium was used was that it protected the logic modules from Thermal Neutron Radiation from the Warhead. Sawing it or putting it in solution would be a very bad thing to do. JM won't even accept material that even has a trace of Beryllium in it. I suspect other refineries have a similar policy.

Beryllium is very light and might be mistaken for an Aluminum Alloy.

Irons said:

Once, at a University where I was on Staff, we acquired some Ballistic Missile logic units that were encased in Beryllium. They were very similar to what was shown in the image. The Gold plating was to prevent oxidation of the Beryllium, which is a severe health hazard. The reason Beryllium was used was that it protected the logic modules from Thermal Neutron Radiation from the Warhead. Sawing it or putting it in solution would be a very bad thing to do. JM won't even accept material that even has a trace of Beryllium in it. I suspect other refineries have a similar policy.

Beryllium is very light and might be mistaken for an Aluminum Alloy.

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great information, i never would have known. thanks again Irons !!

Hi,
Its aluminum, electroless nickel than gold plate. No copper or Beryllium.

If I have to cut it up I will but would like to avoid that, A lot of metal to cut. Not afraid of the acid, will take necessasry precautions. I was thinking of a cell like below. Just thinking.

Has anyone attempted something this large in a cell? If there are issues then I will resort to cutting it up

Not looking to sell it, just want to recover the gold for my own satisfaction

I, for one, wouldn't want to continuously pump concentrated sulfuric. I can't see what you would gain. Why not just use the bottom tank sitting in ice as the stripping tank and forget about the circulation.

I wasn't sure how hot it would get and also wouldn't have to take it apart as often to clean out the gold.

Wondering if anyone has ever tried to strip this large a surface with a cell and how big a supply it would require.

What are the dimensions of that piece?

I think he said 8in x 11in. Big piece for sure. So much acid either way unless you cut it which could be bad.

Berillium copper is also used in the oil and gas industry for wireline service tools. Like MWD (measuring while drilling) or LWD (logging while drilling). Those tools usually have a neutron source and must take high heat and pressures. Makes sense.

Apparently the company I work (I'll call the company Big Red, nickname) for has a big vault of radioactive sources for those wireline tools. Had some training on it a few weeks ago.

Just a thought. If I had that I would get some purple power degreaser or grease lightning degrease and soak it in that.

If it is aluminum with a nickel plating under the gold score the plating in some spots so the degreaser get to the aluminum.
I believe the degreaser oxidizes the aluminum and the plating will release because of the oxidization.

Search the net for removing anodized coatings from aluminum parts. To understand what I am talking about.

Its ~ 8"x11" with the cavities on both sides, see photo in 1st post.

I have many other plated pieces so I think I just need to make a cell and see how it goes.

I will look up the degreaser angle and see how that might work

Any other suggest are welcome

Thanks for the info

goldscraphobby said:

Its aluminum, electroless nickel than gold plate. No copper or Beryllium.

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According to http://wwwchem.uwimona.edu.jm/courses/nickel.html nickel is soluble in dilute nitric acid so it ought to work to dissolve the nickel to release the gold.
At least I would test that road before building a large sulfuric cell.

I don't have any Al-Ni-Au object so I can't test it myself but I would like to know the outcome if someone tests it.

Göran

Thanks,

Any thoughts on a source of nitric? I'm near philadephia.

I do have some very old nitric, around 16 oz. It was lab grade but has been sitting around a long time.

What is considered dilute and how to go about it?

Thanks

Guys it's Aluminium.

Aluminum was an spelling error made by Noah Webster in 1828 that has somehow "stuck" in the US.

Sir Humphry Davy actually settled on the name Aluminium in 1812.

I've got my tongue planted firmly in my cheek when I say this but us Brits all find it funny that you guys keep mis spelling and mis pronouncing the name of this element. :twisted: :twisted: :lol:

You may be able to make what you have work. Using a plastic tub as a cell and a piece of stainless steel as the cathode and your work piece as the anode, the nitric you have may work ok as the electrolyte. The electrolyte should work ok at around 10% tech grade. It should work quicker than a passive bath would. I would go with low voltage and low amps and increase until the stainless starts looking like copper.