# Hi all, a few questions



## samuel-a (Oct 21, 2009)

ok 
first of all, *gold precipitation* , i have made my first test batch of fingers in AP (50g of fingers) to see that every thing going as it should.
the foils came out perfect, rinsed and washed, it yielded around 0.05 - 0.1 g of foils as expected.

View attachment 1


afterwards dissolved with HCL+Cl (around 100ml of HCL and 40ml of Cl) dissolved perfect until no more bubble appear. after rinsing the glass rod i'v come up with a 150ml solution +-

now, 1st Q. - i have purchased ready solution of sodium bisulfite (SBS) 40%, and ended up needed to add 40-50 ml of SBS to the main solution until it got clear and started to drop the gold. is that normal? cause it seems a bit to much for my opinion... but, maybe i'm wrong...?
tomorrow , i'll of course test for remaining gold in the solution.


*next sobject: header pins with HCL*



i have placed a test batch of those kind in a HCL (33%) overnight, thinking only the tin solder and some other base metal (copper?) will dissolve, 
but............
the gold plating is gone as well.... and a redish color is now where the gold plating was. 2nd Q. - what happend? did the gold dissolved?how do i reclaim it? or on the other hand, i miss understand and every thing is ok... what would be the next step?


final sobject (for now  )

i have thrown in an AP solution (2:1 ratio) a mix of flatpacks (with the tin solder), PII cpu and and the kind with the gold plated pins (i think it's Pentium 75 type) and some fingers 3 days now in the bucket... i'v ended up with very turbid solution and some floating foils.... 95% of the foils are still attached, added up some more peroxide... but still, the solution is not reacting any more and i don't want to dissolve the gold...

3rd Q. - what should i do now to salvage the foils that ware separated? and what process should i choose for a better success in processing this batch?



Thank you very very much for any kind of answer
SAMUEL...


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## LeftyTheBandit (Oct 21, 2009)

> 1st Q. - i have purchased ready solution of sodium bisulfite (SBS) 40%, and ended up needed to add 40-50 ml of SBS to the main solution until it got clear and started to drop the gold. is that normal? cause it seems a bit to much for my opinion... but, maybe i'm wrong...?



Generally the use of Sodium *Meta* Bisulite (SMB) is used, and I'm not 100% sure but it is close to being pure. The idea is once the the sulfite is introduced to solution small bubbles of Sulfur Dioxide gas are created and it is this gas that causes the gold to precipitate. SBS may have less available Sulfur to create Sulfur Dioxide gas. This may be the reason you need more to create the same gas that SMB provides.

I think the link to buy SMB is http://www.chemicalstore.com/navigation/detail.asp?MySessionID=294-987651973&CatID=&id=S025, and its cheap.




> the gold plating is gone as well.... and a reddish color is now where the gold plating was. 2nd Q. - what happend? did the gold dissolved?how do i reclaim it? or on the other hand, i miss understand and every thing is ok... what would be the next step?



It is possible that the gold plating still exists but it is covered by a red sludge. Try removing the item and see if you can remove the sludge as it may be hiding the gold plating.

If you have added any hydrogen peroxide in large amounts this would dissolve gold but from what I have read it does not seem you added any peroxide.

The color red generally indicates iron. Tin and aluminum both cause problems with sludge and sludge will cover the plating and guard it from making contact with the AP. Agitation may help circulate the liquid to hopefully knock off enough sludge to expose the metal that the gold is bonded to.

AP is great on fingers because it attacks the copper (extremely well) that the gold is bonded too. If the pins are *not* copper with a gold plating, the AP *may* work, but not with the same clean result. You will have sludge factors. Try vigorous agitation see if the sludge breaks free. Be careful of the vigorous agitation as acid may splash so gear up and use your head.



> i have thrown in an AP solution (2:1 ratio) a mix of flatpacks (with the tin solder), PII cpu and and the kind with the gold plated pins (i think it's Pentium 75 type) and some fingers 3 days now in the bucket... i'v ended up with very turbid solution and some floating foils.... 95% of the foils are still attached, added up some more peroxide... but still, the solution is not reacting any more and i don't want to dissolve the gold...



What is the ambient temperature? Is it cold where you are? A heated solution works much better than a cold one. Agitation is also a major factor. You should have a fish tank bubbler as it helps provide O2 and reduces need for peroxide AND it helps agitate your solution.

Remember AP attacks copper. If you have other metals involved it is not as effective.



> 3rd Q. - what should i do now to salvage the foils that ware separated? and what process should i choose for a better success in processing this batch?



Nitric acid or poor man's AR. This will attack base metals aggressively not just copper. If you have time use very dilute nitric, saves money and works over time....


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## samuel-a (Oct 22, 2009)

lefty, thank you for your replay

1 - the SBS supplier insisted that SBS is basiclly the liquefied version of SMB, and i have read some wher on the forum here the same thing...
BTW, he gave me 1 litre (40%) for free to test
i'm not loaceted in the US, i'm in israel... i gut from them 66lb of 32% HCL for 20$, i guess it's agood price...

2 - i have read somewere that dissolved tin in acid will dissolve gold aswell, so what method should i take? beside electrolysis cell for that pins.... 
i of course don't rule out this option... but if i choose electrolysis cell, does the pins most be clean of tin silder?

3 - the climate here is pretty warm 80-104 F. i don't heat my solution, and had very little time to Agitate.... now 4 days...
i think i'll separate the components and treat each type separatly.... and treat the sludge with hcl/water washes....

3a - you mean, to put the sludge in nitric acid? or the cpu/flatpack themself?

i would love to hear more opinions, as i'm just starting my way and learning through experimenting and mistakes.... 

Thank you, SAMUEL


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## LeftyTheBandit (Oct 22, 2009)

If you have access to nitric acid then that's your best bet in my opinion.

Make sure you rinse the items exposed to HCl very well with a lot of water . If any HCL is still around when you treat with Nitric Acid you will dissolve gold.

The idea is eliminate as much base metal *before *you dissolve the gold. As LaserSteve say's, "Keep your eyes on the gold". Once you get the base metals out of the picture use AquaRegia or Acid Clorox to dissolve the filtered material (gold flakes) with your choice of precipitant.

If you are worried about your first solution dissolving your gold test it with Stannious Chloride. If positive, dilute your mixture and place a piece of copper in solution. If gold is in solution the copper will cement it out.


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## samuel-a (Oct 30, 2009)

well....

i'v decided to drop the hcl,ap,or whatever for the pins...

builted a cell, just missing the lead cathod to which i'll melt next week.

does the pins have to be clean of solder and fine wires that sometimes come out with them in the cell or it dosn't matter?

Thanks again
SAMUEL


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## patnor1011 (Oct 30, 2009)

in my opinion pins has to be as clean as possible of solder/lead. you can make lead cathode out of fish sinkers - cheapest way.


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## samuel-a (Nov 1, 2009)

thank you pantor.

but i don't know how to clean of the solder in an efficient way....

will the tin dissolve in the sulfuric acid? if so, than it's good, cous the gold isn't.... do i understand correct?


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## butcher (Nov 1, 2009)

if unsoldering dropping hot pin knocks off most of lead/tin solder,
lead passivates in sulfuric, this passivated layer protects it from dissolving in sulfuric.
HCl will attack tin, but lead is insoluble as chloride, so lead can form a powdery coating, also slowing attack, brushing or vigerous stirring can assist to remove lead chloride coating, 
HCl and 3% peroxide, will work better to dissove tin in solder, and bubbling action of oxygen from peroxide helps to clear away insoluble lead powders, air from fish tank bubbler assist's here, stirring briskly often also helps.
tin in nitric avoid unless you like to deal with messes.


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## samuel-a (Nov 3, 2009)

Thanks butcher for your insights.

but, please, once and for all, does HCL containing dissolved tin will dissolve also the gold?


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## Barren Realms 007 (Nov 3, 2009)

I think the answer you are looking for is yes the HCL w/tin will disolve gold if mixed with Clorox or other additive that is used to disolve gold. But not with just a mix of HCL/Tin.


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## markqf1 (Nov 3, 2009)

Tin dissolved in hcl makes stannous chloride (sncl2).
It is used to test for gold and other substances but, to the best of my knowledge, doesn't dissolve gold.

An hcl/cl solution will retain both gold and tin.

Mark


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## samuel-a (Nov 3, 2009)

Thank you guys for your answers.
really helped


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## butcher (Nov 5, 2009)

tin will dissolve gold in a melt even at soldering temperature's.
tin will not dissolve gold in a solution, but it will precipitate gold from solutions, as in the stannous chloride test for gold.


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## Harold_V (Nov 5, 2009)

butcher said:


> tin will dissolve gold in a melt even at soldering temperature's.


I wonder how many of the readers understand the solvent power of molten metals?

Harold


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## Barren Realms 007 (Nov 5, 2009)

Harold,

I wonder if they know how it changes the metal structures? I know little about this myself. I use to mix linotype with my lead as a hardener and then would heat treat the cast bullets to harden them further. Didn't have the leading problems you hear most reloaders have.


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## Harold_V (Nov 6, 2009)

Barren Realms 007 said:


> Harold,
> 
> I wonder if they know how it changes the metal structures? I know little about this myself. I use to mix linotype with my lead as a hardener and then would heat treat the cast bullets to harden them further. Didn't have the leading problems you hear most reloaders have.


That's an interesting approach, one I hadn't considered. 

Many of the heat treat methods employed are based on the carbon cycle. That, of course, implies an iron alloy (steel). 

There are non-magnetic alloys that heat treat by other means. While I don't fully understand the process, I have a basic understanding, being that crystals are developed in the metals, often simply by allowing time to pass. Some of the aluminum alloys are amenable to that process, although it can be artificially induced by heat treatment. 

17-4 PH stainless is one of (many) metals that does not rely on carbon for hardening. 

Harold


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## Barren Realms 007 (Nov 7, 2009)

We use to use wheel weight's for our casting. The lead from these had a BNI hardness of 18-20. When we added 10% of the linotype ( which was a tin based linotype from printers presses) it changed the hardness to around 24-26. When we went further and heat treated the cast bullets to just under melting temp and then cooled them it changed the BNI hardness to 29-32. These are the figures I remember they might be a little off it was 20 years ago that I did this. This dosen't sound like a big diffrence but belive me it was. We didn't loose much weight from the castings with the addition of the linotype. The diffrence in the bullets after the process was dramatic, penetration was a lot better and deformation of the bullet was lesss.

The heat treatment of the metal realighns the atomic structure and makes the metal more dense if I'm correct. This is also being done by super cooling items as well.

In iron the carbon makes the metal stronger. And if the metal is treated like the old oriental swords made where it is layered and carbon added between layers and folded many times. The diffrent layers in the fold make the metal srtonger and more flexible because you have many layers working together to resist opposite forces rather than one single layer. You can also get a better edge on the sword because you are feathering many layers rather than one.

If I'm not correct on the following let me know. Pure Platinum jewelery is not used because it is too brittle. Pure gold is too soft and bends.

JMHO, I'm probably wrong in these assumptions and this post will probably look stupid to me in a week or two when I read it again. So I cannot be held responsable for my actions. :roll:


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## Harold_V (Nov 7, 2009)

Barren Realms 007 said:


> If I'm not correct on the following let me know. Pure Platinum jewelery is not used because it is too brittle. Pure gold is too soft and bends.


Pure platinum is anything but brittle. It is very ductile. I have a ribbon of platinum that came from my refining experiences. It's about 18" long, and came from just a small percentage of an ounce of platinum. It is the small coil shown in the picture, below.

Platinum is not used in the pure state for the same reason gold isn't used in the pure state (not commonly, anyway). It's because it, too, is too soft and is easily deformed. 

Harold


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## Barren Realms 007 (Nov 8, 2009)

Thanks for clearing that up for me. I take it that the three glass jars are diffrent states of platinum. I'v seen it discussed about gold craking on the edges because of work stress. Does platinum do this as well? And that is a nice looking coil, I guesss you rolled this yourself?


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## Oz (Nov 8, 2009)

Platinum can become brittle even if pure, if it is melted with an acetylene torch.


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## Barren Realms 007 (Nov 8, 2009)

Oz, does it do any harm to the metal other than making it brittle? I use an acetylene tourch with a turbo tip set up. Does it do any damage that would effect the sale of a nugget?



Oz said:


> Platinum can become brittle even if pure, if it is melted with an acetylene torch.


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## Oz (Nov 8, 2009)

Acetylene flames tend to be dirty with carbon and it is this carbon that contaminates the platinum that makes it brittle.

Most platinum buyers would prefer to buy platinum in sponge form since it is easier to put into solution for checking purity or making compounds. Ever try taking a decent size platinum button into AR even under heat? Set aside a good bit of your day. 

As to a brittle button affecting sale value, it may if part of how they are judging the purity of your platinum is its ductility. Very slight contamination of other elements affects the normally malleable nature of pure platinum.


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## Harold_V (Nov 8, 2009)

Barren Realms 007 said:


> Thanks for clearing that up for me. I take it that the three glass jars are diffrent states of platinum.


Correct. Left one is the platinum as recovered with ammonium chloride. Middle one is the calcined material (platinum sponge) and the right side is a melted button. 



> I'v seen it discussed about gold craking on the edges because of work stress. Does platinum do this as well?


I did no annealing with the coil in the picture---but the slightest contamination can cause platinum to "alligator". It can be caused by carbides that form when melting the platinum (read what Oz said), or by traces of other elements, primarily silver.



> And that is a nice looking coil, I guesss you rolled this yourself?


Yes, with the set of power rolls I used to own. When I retired and moved to Washington, they were sold to one of my customers. The platinum coil was my first attempt at refining platinum. 

For the sake of clarity, the button shown in the picture (front, center) is slightly larger than a troy ounce, and, like the coil, is still in my possession. 

Harold


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## Barren Realms 007 (Nov 9, 2009)

Oz said:


> Platinum can become brittle even if pure, if it is melted with an acetylene torch.




Ok that brings up a couple of questions then.

Does this mean you can't use an oxy/acet tourch to melt platinum? 

Does an oxy/acet tourch get hot enough to burn the carbon and not contaminate the platinum?

If oxy/acet is ok to use here is my next question. The acet tourch I use has a tip like a brazing tip on an oxy/acet but bigger around(size of pinky finger). When it is opened up the flame is close to the tip like an axy/acet barzing tip. This burns hot enough to silver solder up to 1" copper for this tip. A lot hotter than a mapp gas tourch too( I use both of them on a regular basis). With it burning at these temps would it rule out competently using it to melt platinum with out contaminating it just because it is acet ?


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## Barren Realms 007 (Nov 9, 2009)

Harold_V said:


> Barren Realms 007 said:
> 
> 
> > Thanks for clearing that up for me. I take it that the three glass jars are diffrent states of platinum.
> ...



All 3 of those look nice Harold. The roll looks very good. Do you remeber how many times you ran it thru the press? I take it that it was a button when you started with it.

And the carbides that form that can be from carbon or any other elemental contaminant in the atmosphere then. Ok am I correct in understanding that it is recomended that platinum should be melted in a vacume? Or can an inert gas like argon be injected into a crucible to get a similar desired effect?

Sorry about getting off thread. :roll:


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## Harold_V (Nov 10, 2009)

Barren Realms 007 said:


> All 3 of those look nice Harold. The roll looks very good. Do you remeber how many times you ran it thru the press? I take it that it was a button when you started with it.


Correct. I don't recall the actual weight now, but it was in the neighborhood of a third of an ounce. Needless to say, it started out as a button. As a result, it was run through the rolls several times. That's normal for rolling. Its not accomplished with single passes, but a series of repetitive passes, each one making the material thinner than the last. Perhaps a half dozen passes total for the strip. 

The material isn't flawless---there's a little open place or two where there was a low spot in the button, and there's a hint of aligatoring on the very edges. A sign that the platinum was not perfectly clean, nor did I expect it was. It was simply my first experience, and I wanted to explore how it turned out. 



> And the carbides that form that can be from carbon or any other elemental contaminant in the atmosphere then. Ok am I correct in understanding that it is recomended that platinum should be melted in a vacume? Or can an inert gas like argon be injected into a crucible to get a similar desired effect?


What is recommended is a hydrogen torch, which eliminates introduced carbon. An inert atmosphere certainly wouldn't hurt, but isn't a requirement. 
I melted all of my platinum with a torch, using natural gas, or oxy/acet. You can get away with that setup so long as you use an oxidizing flame instead of a reducing flame. It's just the opposite of what you'd want when melting alloy gold or silver, but it also yields the hottest flame, which is important when melting platinum. It's pretty hard to melt much more than an ounce and achieve good results with a torch. Induction melting is the way to go, but few have that luxury. Even fewer have enough platinum to make that a concern. I accumulated only about 75 ounces of platinum in my more than 20 years of refining, and I handled a considerable amount of dental alloy in my years. 

Harold


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## Barren Realms 007 (Nov 10, 2009)

What supprised me about the platinum you rolled out is that it dosen't look like it spread out sideways just length wise. Did you do somethign to it to make it spread that way?


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## goldsilverpro (Nov 10, 2009)

> What supprised me about the platinum you rolled out is that it dosen't look like it spread out sideways just length wise. Did you do somethign to it to make it spread that way?


That's the way it always works when you put metal through a set of rolls.


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## Harold_V (Nov 11, 2009)

goldsilverpro said:


> > What supprised me about the platinum you rolled out is that it dosen't look like it spread out sideways just length wise. Did you do somethign to it to make it spread that way?
> 
> 
> That's the way it always works when you put metal through a set of rolls.


Yep! If you want it wider, you must start with a wider button or ingot, or you must send it through the roles to widen it to the desired width, with a little excess. It is then rolled @ 90° to the width, to the desired thickness. From this, you can conclude that the button from which the ribbon was rolled was roughly the size of the ribbon. It tapers on each end, just as the button diminished in width at each end. 

Harold
Edit:
It's fun to watch the rolling process. The outgoing metal is moving at a faster rate than the ingoing metal. The metal is displaced in the process of rolling, making the ribbon ever longer as it gets thinner.


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