melting foils

[teclu]

Hello everybody!

Dissolving more types of pins in nitric acid, - I've already told you about a few types here on the forum - I got approximately 400 g of foils. Here are a few pictures of these:

http://i39.tinypic.com/n4eoll.jpg
http://i42.tinypic.com/6xk9ko.jpg
http://i40.tinypic.com/2qg5h5d.jpg
http://i42.tinypic.com/388h7ch.jpg

As I already mentioned, I want to melt these foils and offer them to a refiner. I could use some advices from you in the matter of melting. I got this electrical furnace, which has a graphite crucible (1 kg capacity), here is the picture:

http://i42.tinypic.com/2672m4g.jpg

Who can tell me which are the steps in working with this melting method (electrical furnace) for me not to lose the foils obtained by sweat and a lot of fume.... of course.
What about melting fluxes?
I would want to melt in smaller amounts (max. 1 troy oz). Can I drop the melt in a bowl with water? The casting form is not so important for me.
Any advice is welcomed!

Thanks a lot!
teclu from Transylvania

 

[4metals]

Fill the crucible in the melter about 2/3 full with the foils, they must be dry. As the melt heats up the level of the foils will shrink in the crucible and you can add more dry foils until they are all in the crucible. If the foils melt completely before you add more do not add any more foils to molten metal. You can push the foils down to compact them by using a graphite rod but this is only a preference not a necessity. When the foils are all in the melter you can add a teaspoon full of borax to the top of the melt, this will help the molten metal flow out completely when you pour.

When the foils are molten pour them into a pre-heated mold, if the mold is anything but graphite, carbonize it to prevent sticking.

You will be better served if you intend to sell it to a refiner if you pour it into a bar so you can drill it and assay it so you have an idea of its worth.

 

[goldsilverpro]

You have nitric and muriatic. Why not purify (refine) them in AR before melting? It's easy. I can guarantee the foils aren't pure gold. They contain small amounts of cobalt or nickel used to harden the gold.

How much weight do you have?

 

[lazersteve]

I'm with GSP, dissolve the foils in HCl and Clorox in a matter of minutes, filter clear and precipitate with SMB. For about an hours worth of work and a few dollars work of chemicals you can refine the foils. Then melt the properly washed powder in your furnace.

Steve

 

[AurumShine]

Goldsilverpro and Lasersteve ask right .

 

[teclu]

Fill the crucible in the melter about 2/3 full with the foils, they must be dry. As the melt heats up the level of the foils will shrink in the crucible and you can add more dry foils until they are all in the crucible. If the foils melt completely before you add more do not add any more foils to molten metal. You can push the foils down to compact them by using a graphite rod but this is only a preference not a necessity. When the foils are all in the melter you can add a teaspoon full of borax to the top of the melt, this will help the molten metal flow out completely when you pour.

When the foils are molten pour them into a pre-heated mold, if the mold is anything but graphite, carbonize it to prevent sticking.

You will be better served if you intend to sell it to a refiner if you pour it into a bar so you can drill it and assay it so you have an idea of its worth.

4metals,
Many thanks!

You have nitric and muriatic. Why not purify (refine) them in AR before melting? It's easy. I can guarantee the foils aren't pure gold. They contain small amounts of cobalt or nickel used to harden the gold.

How much weight do you have?

gsp,

Yes, I know that the foils aren't pure gold, but I'm not interested in refining because I can be obtained, here in my country(my sale price), maximum 85% of KITCO.
Now I have 430 grams of dry foils, but I have also aprox. 20 kg of pins for processing.




steve and aurumshin, however many thanks!


teclu from Transylvania

 

[goldenking]

Hello teclu Nitric acid is expensive not cheap you waste nitric acid on pins as water . How much dollar you waste on pins ?

 

[teclu]

Hello teclu Nitric acid is expensive not cheap you waste nitric acid on pins as water . How much dollar you waste on pins ?

goldenking hi,

I pay $2,5/1kg HNO3-69% and $30-$100/1 kg pins.

teclu

 

[teclu]

Hello everybody!

After I analyzed in detail and, of course, listening to your advices regarding the next steps for the foils, I have to admit, that dissolving them is the most indicated solution (before melting). As I said, I have 69% nitric and 37% muriatic. Until now I didn’t work with AR, that’s why tomorrow I want to begin the process on smaller amounts of foils. Regarding the temperature, is it enough if outside is 30 C, or the solution must be heated?
From the subjects posted by you, this is how I understand AR works: I add 4 ml muriatic on 1 gram of foils, afterwards I add 1 ml of nitric. I’ll take some pictures of what I’ll work tomorrow, but until then, please tell me have I mistaken in something like: percentage of the two acids, does it need water, is the stirring necessary when I add nitric?
I remain profoundly indebted to you!

teclu

 

[lazersteve]

Teclu,

You can dilute the AR with an equal volume of water to keep the fumes down. If you use nitric add small amounts to be certain you don't over add as excess has to be removed ('denoxxed').

Heating speeds up the process.

HCl-Cl plus lots of stirring will do the job also and save valuable nitric acid, plus there is no need to denoxx the solution.

Steve

 

[teclu]

Teclu,

You can dilute the AR with an equal volume of water to keep the fumes down. If you use nitric add small amounts to be certain you don't over add as excess has to be removed ('denoxxed').

Heating speeds up the process.

HCl-Cl plus lots of stirring will do the job also and save valuable nitric acid, plus there is no need to denoxx the solution.

Steve

Hi Steve!

Thanks for your quick answer, I'll let you know about the work progress. By the way, I realise, that I'm just a few steps from "El Dorado" or "The Yellow End", even if at the beginning I didn't thought I'll make it this far. Fortunetly procurring the chemicals (nitric too) isn't yet a big problem here in my country.

teclu

 

[goldenking]

Hello teclu Please tell us your country name you are living in china or any Asian countries because acid is very cheap in those countries who is neighbor of china .

 

[teclu]

Hello teclu Please tell us your country name you are living in china or any Asian countries because acid is very cheap in those countries who is neighbor of china .

goldenking Hi,

Transylvania-Romania-Europa.... and China is not even first neighbor for me.

http://en.wikipedia.org/wiki/Transylvania

The nitric is not free here,...for some can be cheap and expensive for others, depending on what kind of material/pins process.

teclu

 

[goldenking]

Hello teclu I am very afraid with youu......becauus..e you...rr vampire .
whole forum is afraid with you .Next time you neve..r sho..w yourrrr country..yy because i am very nervous . you show your living on Moon same me . AHHHHHHHHHHHHHHHHHHHH Vampire :shock: :shock:

 

[teclu]

Hello everybody,

I put in AR 2 grams of mixed foils from five types of pins, after that I put water, and here are the results:
(pictures are made at 2 hours after that)

http://i43.tinypic.com/xhyjt.jpg
http://i39.tinypic.com/256ui5e.jpg
http://i41.tinypic.com/289kif.jpg
http://i42.tinypic.com/sof9ty.jpg

Solution is not so clear and something like a gray mud are on the bottom of erlenmayer, of course this little mud are very fineness and in pictures not see well(the mud) .

Waiting your opinions and suggestions.

Many Thanks!

teclu from Transylvania

 

[AurumShine]

Hello teclu

The mud is silver and insoluble particles of dust in acid. save this mud because it is silver some pins is 24 k plated but some less karat plated. Filter this mud and then neutralized your acid with urea or evaporation evaporation is good for large batch for experimentally use urea because urea is fast but urea method loss some gold then use smb and stir well solution is goes to black put this flask on aside for two day(my suggestion is that put this black solution in beaker ) after two days whole black powder is settle out in the bottom then siphon off upper solution with medical syringe remove niddle attach a noon flexible mini pipe because siphoning is main key of your purity of gold then add distill water in beaker boil them because distill water dissolve any nitrates three time wash with distill water and siphon off then add HCL until HCL not discolored and boil them and siphon off then add water repeat three times and siphon off and then add ammonia hydro oxide for removing any silver Siphon off then add water and siphon off and dry this mud with low heating (so painful) when you get 2 or 3 gram of gold powder then melt it .start your large batch with 10 grams or less if you put your whole gold flakes you may loss gold because it is your starting .

 

[goldsilverpro]

I doubt that the mud is silver, since I can see no source for it. Maybe it is tin, in the form of metastannic acid. Was there any solder on those pins? I guess there could be some silver, however, in the newer non-lead solders.

Gold plating is used on electronics primarily because of it's high conductivity, non-corrosiveness, and it's solderability. Since gold is very soft, very small amounts of cobalt or nickel are added to the gold plating bath to make the gold deposit harder. This is used primarily on places where there could be wear, such as pins and fingers. The resulting deposit contains a minimum of about 99% gold purity and is usually about 99.9%, with the remainder Co or Ni. A less pure gold would result in lower conductivity, which is undesirable. Although there is no technical advantage to this, these harder golds tend to produce a shinier deposit than the pure gold (9999+) that is used on such parts as CPU packages. In the electronics industry, the purity of gold plating is never expressed in karats. I know of no electronic gold plating that contains silver. I can think of no technical reason to use it.

Gold plating on jewelry is different. The jewelry industry wants different shades or colors of gold and these are expressed in karats. In actuality, the gold content of these "color gold" deposits are higher than the karat shade of gold that is produced - don't ask me why. To produce a green gold, silver is added to the bath.

 

[lazersteve]

The mud is likely just debris from the pins or as GSP suggested insoluble solder compounds.

You should filter the yellow auric chloride solution through a Charmin plug setup to remove the fine particles and then precipitate the gold and wash as normal.

Steve

 

[teclu]

Hello teclu

The mud is silver and insoluble particles of dust in acid. save this mud because it is silver some pins is 24 k plated but some less karat plated. Filter this mud and then neutralized your acid with urea or evaporation evaporation is good for large batch for experimentally use urea because urea is fast but urea method loss some gold then use smb and stir well solution is goes to black put this flask on aside for two day(my suggestion is that put this black solution in beaker ) after two days whole black powder is settle out in the bottom then siphon off upper solution with medical syringe remove niddle attach a noon flexible mini pipe because siphoning is main key of your purity of gold then add distill water in beaker boil them because distill water dissolve any nitrates three time wash with distill water and siphon off then add HCL until HCL not discolored and boil them and siphon off then add water repeat three times and siphon off and then add ammonia hydro oxide for removing any silver Siphon off then add water and siphon off and dry this mud with low heating (so painful) when you get 2 or 3 gram of gold powder then melt it .start your large batch with 10 grams or less if you put your whole gold flakes you may loss gold because it is your starting .

Hi Aurumshin,

Thanks for your detailed explanation, surely it will be very usefull for me.

teclu

I doubt that the mud is silver, since I can see no source for it. Maybe it is tin, in the form of metastannic acid. Was there any solder on those pins? I guess there could be some silver, however, in the newer non-lead solders.

Gold plating is used on electronics primarily because of it's high conductivity, non-corrosiveness, and it's solderability. Since gold is very soft, very small amounts of cobalt or nickel are added to the gold plating bath to make the gold deposit harder. This is used primarily on places where there could be wear, such as pins and fingers. The resulting deposit contains a minimum of about 99% gold purity and is usually about 99.9%, with the remainder Co or Ni. A less pure gold would result in lower conductivity, which is undesirable. Although there is no technical advantage to this, these harder golds tend to produce a shinier deposit than the pure gold (9999+) that is used on such parts as CPU packages. In the electronics industry, the purity of gold plating is never expressed in karats. I know of no electronic gold plating that contains silver. I can think of no technical reason to use it.

Gold plating on jewelry is different. The jewelry industry wants different shades or colors of gold and these are expressed in karats. In actuality, the gold content of these "color gold" deposits are higher than the karat shade of gold that is produced - don't ask me why. To produce a green gold, silver is added to the bath.

Hi GSP,

The pins which I processed were NOS, I think you're right, it is silver, because between those processed pins I had some Russian ones, and the producer's catalog indicates the presence of silver in the plating. Thanks for your other informations about the "secrets of the yellow" too.

teclu

The mud is likely just debris from the pins or as GSP suggested insoluble solder compounds.

You should filter the yellow auric chloride solution through a Charmin plug setup to remove the fine particles and then precipitate the gold and wash as normal.

Steve

Hi Steve,

Short and to the point, as usual. Many thanks!

teclu

 

[goldsilverpro]

teclu,

Someone mentioned some Russian pins awhile back that had silver plating underneath the gold. I ran some very high-grade (1 tr.oz. of gold/pound) pins from the 30s or 40s that had the same. The problem with this is that, eventually, the silver will migrate up through the gold and will form tarnish on the gold surface. For this reason, I don't think this combination is used any longer, at least in the U.S. I have never run across pins plated with a gold/silver alloy. I used to work for a large company that sold at least 100 (maybe, 200) different varieties of gold plating baths. We had a gold/silver bath on the list but, I don't ever remember our selling any of it.