# Best method for processing 4.5 lbs of pins.



## stihl88 (Apr 3, 2012)

Well Ive spent a month of Sundays individually snipping these pins from their host...

Ive got hands that could crush Hercules nuts after all the snipping Ive done. In total there are individual 12 pins per connector, i had 4000 connectors.
Each connectors pins were snipped off in 4 snips meaning Ive done 16,000 individual snips...

In total their are 48,000 individual pins in that jar.

I'd sit on the recliner for an hour or two a night and slowly whittle away at these connectors. I'm just glad it's a hobby cos I'd be flat broke working at this rate 


What would be the preferred method of processing these pins? They appear to be copper based.
Ive got about 5 liters of nitric acid and Ive also got a sulphuric cell with a copper basket at my disposal which is about the same size cell we typically see here on the forum in the Pyrex dishes.


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## Harold_V (Apr 3, 2012)

Sulfuric cell, assuming you can keep them from leaking from the basket. 

Harold


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## Geo (Apr 3, 2012)

the component that you cut the pins from, what is that? is it some sort of relay? have you busted one open? it looks like the gold extends all the way inside. you may have snipped for nothing if these can be crushed and theres more gold inside. if its a relay, there could be silver too.


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## dtectr (Apr 3, 2012)

For the risk harold stated, I would use PoorMan's AR, using INCREMENTAL additions of your nitrate of choice - I use potassium, myself. FWIW


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## gold4mike (Apr 3, 2012)

An alternative method for getting the gold off of them, since there appears to be no tin, is "poormans" nitric.

I'm processing roughly 40 pounds of pins for a percentage of the gold and am using battery acid ($28.00 for five gallons locally) with sodium nitrate. I put about an inch or so (depth) of pins in the beaker and add two or three inches of sulphuric acid, then 2 heaping teaspoons of sodium nitrate.

Cover with a watch glass, wait until no more brown fumes, add another teaspoon, etc. After 4 or five additions of sodium nitrate I dump all the liquid, including the foils, into a bucket with a quart or so of water already in it. I let it cool overnight then pour through a filter.

Add more pins to the partially dissolved mass, add acid, sodium nitrate, etc. I'll continue until all the pins are dissolved and then process the foils and filters.

I found that the water bucket was necessary because, if I left the contents in the beaker, I was left with a solid blue chunk of copper nitrate that slowed my progress. If you have enough water it will stay in solution.

I'm now using an electric griddle as a hotplate, with a half inch or so of sand on it. I can fit four 2 liter beakers on it at a time.


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## rewalston (Apr 3, 2012)

I have a question about pins. Most of the posts I've seen talk about using Poorman's Nitric to rid the base metals. I have some sulfuric acid but cannot get any nitrates. I don't have all the parts yet for the acid cell, still lacking the copper mesh and a charger. So I'm wondering if I could use AP for the pins, I know that it would put a lot of copper into the solution but right now AP is the only process that I have available. Also when you pre-treat the pins in straight HCl to remove the solder, after filtering out any possible silver from the solder. I know you can keep using the HCl until it's saturated with tin but what do you do with said acid. I'm assuming you would not want to put that into your stock pot because of the problems with tin in other reactions. I might be wrong but that's why I'm asking.

Rusty


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## martyn111 (Apr 3, 2012)

rewalston said:


> I have a question about pins. Most of the posts I've seen talk about using Poorman's Nitric to rid the base metals. I have some sulfuric acid but cannot get any nitrates. I don't have all the parts yet for the acid cell, still lacking the copper mesh and a charger. So I'm wondering if I could use AP for the pins, I know that it would put a lot of copper into the solution but right now AP is the only process that I have available.



You could use the 'crock pot' method, warm to hot hydrochloric acid will dissolve away the pins leaving either gold flakes / foils or gold tubes. 
This method could also be used to reduce steps if your pins have solder on them.


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## rewalston (Apr 3, 2012)

martyn111 said:


> rewalston said:
> 
> 
> > I have a question about pins. Most of the posts I've seen talk about using Poorman's Nitric to rid the base metals. I have some sulfuric acid but cannot get any nitrates. I don't have all the parts yet for the acid cell, still lacking the copper mesh and a charger. So I'm wondering if I could use AP for the pins, I know that it would put a lot of copper into the solution but right now AP is the only process that I have available.
> ...



Once the acid is saturated does everything (after filtering of course) go into the stock pot?

Rusty


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## martyn111 (Apr 3, 2012)

I would have thought that once the acid is saturated with copper anything of value would have been pushed out of solution by the copper, as would be the case with values dissolved in AP.
I would hope that someone with a deeper understanding of chemistry will chime in if my assumption is incorrect.


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## stihl88 (Apr 3, 2012)

Harold, the mesh is quite fine and wont allow the pins to fall through. (It's from Lazersteves site)

Geo, they are just a plug/connector component, not a relay. Ive investigated the internal part of the pin and they aren't plated inside except for the side walls
so i made the decision to sacrifice that 5% of internal gold and just snip the pins.

I think i will try these two methods.

-I'll run a batch through my sulphuric cell and see how they turn out, pretty straight forward.

-I'll weigh 10 or even 100 grams of pins and then figure out how much Nitric is required to dissolve 10g of copper and go for it.
At this stage I'm hoping the copper will dissolve leaving me with nice little floating foils, actually sinking foils would be better  

I'm hoping I'll get at least 10g of gold for all my troubles. 
These pins were in individual containers of 100 in each, each container was labeled "ERICSSON" so i assume they were manufactured by Ericsson's. 
The pins appear to be quite heavily plated compared to flash plated stuff so I'm hoping Ive got a good rich batch but will find out soon.

Stay tuned for more pictures.


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## Marcel (Apr 3, 2012)

stihl88 said:


> I'm hoping I'll get at least 10g of gold for all my troubles.
> .



1% fine gold yieldfor high grade goldplated pins is standard, let´s see if these pins can beat this.....


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## maynman1751 (Apr 3, 2012)

martyn111 said:


> I would have thought that once the acid is saturated with copper anything of value would have been pushed out of solution by the copper, as would be the case with values dissolved in AP.
> I would hope that someone with a deeper understanding of chemistry will chime in if my assumption is incorrect.



Copper in solution will not cement out values. Only solid metallic copper will do that. I think that is what you're asking!!??


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## gold4mike (Apr 3, 2012)

Rusty,

I get my Sodium Nitrate from Duda Diesel's website. I'm not sure if they ship to Canada but it's worth checking. You should also be able to get it from your local farm supply store.


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## martyn111 (Apr 3, 2012)

maynman1751 said:


> martyn111 said:
> 
> 
> > I would have thought that once the acid is saturated with copper anything of value would have been pushed out of solution by the copper, as would be the case with values dissolved in AP.
> ...



Not quite what I was asking, the copper (in solid form) being dissolved by the hydrochloric acid will cement out the values as it is taken into solution was what I was saying.


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## rewalston (Apr 3, 2012)

gold4mike said:


> Rusty,
> 
> I get my Sodium Nitrate from Duda Diesel's website. I'm not sure if they ship to Canada but it's worth checking. You should also be able to get it from your local farm supply store.



I've checked the local farm supply and they won't even talk about sodium nitrate.

Rusty


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## Acid_Bath76 (Apr 3, 2012)

try SPECTRACIDE. They make a tree stump remover powder that is 98% potassium nitrate. Worst case scenario, you could probably order it online without the hassle of purchasing "labelled Sodium Nitrate".


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## dtectr (Apr 4, 2012)

AP was actually my 1st choice - it's slower but fewer "issues". Make sure to read lazersteve's "CuCl II" document on his website. 
"Nitric" = "No-No" until you have more experience with acids and their unique reactions with e-scrap.


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## stihl88 (Apr 4, 2012)

dtectr said:


> AP was actually my 1st choice - it's slower but fewer "issues". Make sure to read lazersteve's "CuCl II" document on his website.
> "Nitric" = "No-No" until you have more experience with acids and their unique reactions with e-scrap.



If your going to run AP then it should be made mandatory that the AP user invests in an air bubbler, it works wonders.


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## goldenchild (Apr 4, 2012)

The cell is the easiest and cleanest way to do this period. You'll be done in a half hour or less. If you use any other method there are down falls.

AP - inevitably some gold will go into solution and since there is so much copper it will plate out. So you will not only have to remove and filter the foils from all those tiny pins but also have to be on the lookout for a terribly fine black dust in a very dark solution. Time.

Crockpot - that’s a good amount of copper to try to dissolve with an acid that’s not very good at dissolving copper. You'll probably have to keep adding acid to it also. The pins would also have to be damaged in order for the acid to effectively get at the copper. Incineration comes to mind. Time.

Poor man’s nitric - the waste stream will be quite large for such a small amount of material. You'd also have to contend with the blocks of nitrate and copper sulphate like mentioned by gold4mike. Incineration. Time.

Using the cell would be a breeze compared to these other methods and since you have a cell at your disposal you should use it. Knowing what I know now if I didn’t have a cell available yet I would put the scrap to the side until I got one.


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## rewalston (Apr 4, 2012)

Thanks for the replies guys. As I said I have almost everything for the cell, just lack the funds to finish it. I'm hoping that I can find the rest soon. I'm still pulling things apart anyways.

Rusty


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## jack_burton (Apr 4, 2012)

Having just done pins that look exactly like these, sulfuric cell is the way to go. Just fashion the basket from the sheet of L.S. copper and you are off to the races. There's a video, actually, I made for a client on my you tube channel, [stt]but I don't have access to the link right now. I think you can click on the video on the main page of my site and it will take you to Youtube and you can see my channel there.[/stt] Hope that helps.

Here's the link: http://www.youtube.com/user/dominionrefining
EDIT: Added link.


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## johnny309 (Apr 4, 2012)

Your choice considering material in hand(aka ...acids,setup,etc).

1.The sulphuric will work faster,but you will not have all the gold out(the pins must to have good electrical connections to let the electricity thru)
2.with nitric ...you generate a lot of waste solution,but the material seem clean
3.AP is good but...it will take you about 2 week with this amount and lost of gold in filters.

I'd say to go with nitric acid(which you already have).....use distiled water.....and pleanty of open air(just for the safety)......
I take the risks and "bet" on 12.8 grams of gold.


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## dtectr (Apr 5, 2012)

2 problems with the cell for pins :
1- no way will you be done in short amount of time, even with tumbler- outer layer of pins will form a Faraday shield - outer pins will overstrip, while inner ones will barely be touched. If you do leave the pins in long enough to strip inner ones, outer ones will strip down to copper, loading acid with base metals and overheating it, as well. Even with a tumbler, stripping will be uneven. I, for one, wish to get ALL my gold.
2- remember we are dealing with a newer member, without our universal experience (if you believe that, I have some land to sell you in Cocao Beach! Lol) if I were doing them, I would use Poor Man's AR, but its m8 me - its our friend here. When the guru me the cell recommends another process for pins, I listen. 
That's just me, FWIW


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## Marcel (Apr 5, 2012)

Some here will beat me for this, but I will still suggest to think about:
Using a furnace you could melt the whole batch. Gold will sink to the bottom. Dont pour the molten metal out, heat it for at least 30 minutes at melting temperature,let is slowly get cold , then remove it.
The Gold will have sunk to the bottom, copper and other metals will stay on top, so then you just need to saw off the bottom and have your gold.
Of course some of the gold will be lost, but not too much and there will be losses in chemical process for most of us amteurs as well.
Now I have to duck and hide... :lol:


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## goldenchild (Apr 5, 2012)

dtectr said:


> 2 problems with the cell for pins :
> 1- no way will you be done in short amount of time, even with tumbler- outer layer of pins will form a Faraday shield - outer pins will overstrip, while inner ones will barely be touched. If you do leave the pins in long enough to strip inner ones, outer ones will strip down to copper, loading acid with base metals and overheating it, as well. Even with a tumbler, stripping will be uneven. I, for one, wish to get ALL my gold.
> 2- remember we are dealing with a newer member, without our universal experience (if you believe that, I have some land to sell you in Cocao Beach! Lol) if I were doing them, I would use Poor Man's AR, but its m8 me - its our friend here. When the guru me the cell recommends another process for pins, I listen.
> That's just me, FWIW



I would have brought up AR but those are bad word's in these parts when it comes to anything other than karated gold. It's bad EVEN when talking about karat gold for that matter, even though it's really the way its done on the outside.



Marcel said:


> Some here will beat me for this, but I will still suggest to think about:
> Using a furnace you could melt the whole batch. Gold will sink to the bottom. Dont pour the molten metal out, heat it for at least 30 minutes at melting temperature,let is slowly get cold , then remove it.
> The Gold will have sunk to the bottom, copper and other metals will stay on top, so then you just need to saw off the bottom and have your gold.
> Of course some of the gold will be lost, but not too much and there will be losses in chemical process for most of us amteurs as well.
> Now I have to duck and hide... :lol:



No.


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## dtectr (Apr 5, 2012)

I just re-read my post from last night I wish to reiterate that I'm using a dumb smartphone and t9 input so it sometimes finishes words for me, i.e. "of" and "me" are both spelled by the same keystrokes- but it "remembers" which word I used last and if it gets too late for the old man I don't catch it, if what I write comes out too unintelligible let me know and I'll try to correct it, I don't want to pass on bad info even unintentionally.


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## Harold_V (Apr 5, 2012)

johnny309 said:


> 1.The sulphuric will work faster,but you will not have all the gold out(the pins must to have good electrical connections to let the electricity thru)


Not true. One does not dump the pins in and assume they get stripped. They should be stripped, then dumped and poured in a second time. The chances that any gold will be left behind is exceedingly small. Do remember that the removal process is not an electrical process directly---gold is dissolved by the creation of persulfuric acid in the proximity of the anode, so pins that aren't truly conducting will still be subjected to some of the acid. A second running will pretty much ensure all gold is stripped. Leaves the owner with scrap that is readily marketable, as a bonus.



> with nitric ...you generate a lot of waste solution,but the material seem clean


Three issues with the use of nitric. It is far more expensive. It yields a total loss of the base materials. It creates a huge volume of gasses. One is far better served to strip the pins, assuming a stripping cell is at one's disposal. 



> I'd say to go with nitric acid(which you already have).....use distiled water


Unless silver is involved (it isn't), the call for distilled water is unwarranted. Certainly not a bad choice, but not necessary. Tap water serves perfectly well. The only possible argument against tap water is that it contains some chlorine, thus the risk of dissolution of values. Ain't gonna happen with so much base metal present. 

Harold


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## Harold_V (Apr 5, 2012)

Marcel said:


> Some here will beat me for this, but I will still suggest to think about:
> Using a furnace you could melt the whole batch. Gold will sink to the bottom. Dont pour the molten metal out, heat it for at least 30 minutes at melting temperature,let is slowly get cold , then remove it.
> The Gold will have sunk to the bottom, copper and other metals will stay on top, so then you just need to saw off the bottom and have your gold.
> Of course some of the gold will be lost, but not too much and there will be losses in chemical process for most of us amteurs as well.


Please do not post such nonsense. Those with a lack of understanding assume it to be true, then we spend all of our time trying to undo the damage created. 

Gold, once alloyed, will not "settle out". It is *extremely unusual *for metals to stratify upon cooling.. otherwise it would be unnecessary to process chemically. 

There are some metals that will not alloy readily with other metals. Gold, copper, zinc and tin are all very willing to do so and are not separated easily once alloyed. 



> Now I have to duck and hide... :lol:



You damned well will if you post such nonsense again. We have a strict policy about _*misinformation*_ on this forum. 


Harold


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## stihl88 (Apr 5, 2012)

Thanks for getting things back on track their Harold, i couldn't believe some of the suggestions that were starting come about (come on guys you should know better, if not, read Hokes and study the forum)

-Now getting back on track.

I conducted a small test with nitric using 100g of pins. I had some very nice foils floating and to my estimation might equate to approx 1g of Au.
After i dissolved in AR, evaporated, diluted then dropped it looked like i had a nice dark precipitation. After drying the precipitated Au out i
proceeded to melt it, but to my surprise it didn't really melt like usual the Au never quite came together, when it was cooling as usual i tried to pluck
the button from the melting dish but it hadn't solidified yet, this wasn't right i thought, ah I'll re-heat it then wait a little longer for it to cool.
But i waited for a long time, until the Borax started to cool and crack (you know the sound) and it was still molten.

The only thing i can suggest is that they are Tin plated Also?

Anyway, my intention of the Nitric was to determine the amount of Au per pound of pins.
I will be processing these in my Sulfuric cell from now but wont be able to determine the amount due to the cell already having Au in it...


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## goldenchild (Apr 5, 2012)

On a side note. What's going on with the subscribe feature? It used to be that you could mark a checkbox and any thread you posted to would automatically subscribe. I don't even see where you can subscribe to threads anymore.


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## jimdoc (Apr 5, 2012)

goldenchild said:


> On a side note. What's going on with the subscribe feature? It used to be that you could mark a checkbox and any thread you posted to would automatically subscribe. I don't even see where you can subscribe to threads anymore.




It probably has to do with this;

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=64&t=13308#p133480

Jim


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## dtectr (Apr 6, 2012)

stihl88 said:


> Thanks for getting things back on track their Harold, i couldn't believe some of the suggestions that were starting come about (come on guys you should know better, if not, read Hokes and study the forum)
> 
> -Now getting back on track.
> 
> ...


I usually try to avoid quoting as it tends to hog up space, but I want to make sure the point I'm addressing is clear - if pins are bronze or close relative, it will contain from 5 to 7% tin in the alloy - no way around it - no tin, not bronze. 
So, in your 100g sample of pins, you had about 5 to 7g of tin, which turned into a roughly equivalent amount of metastannic acid. Even on higher grade pins, your yield would be, approximately (I don't have my yield data handy, so running off memory which is a dangerous proposition) 1.5 to 2.5g per kilo. 100g = 0.1 kilo. 1/10 of yield leaves 0.15 to 0. 25g of gold, best case - assuming there is none lost in the tin goo. 
That amount would be barely visible, let alone recoverable. If you had enough powder to melt, them very little of it was gold. The lower temp at which it stayed molten sounds more like lead or zinc to me though I'm not sure where it would have come from. 
Bottom line, IMHO pins in nitric is usually a bad idea.


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## Geo (Apr 6, 2012)

i never heard of bronze being used to make connector pins. normally its either copper or brass. bronze is more corrosive resistant than brass, but thats why they coat them in gold. im not saying its not bronze, just that i dont think it would make much sense for them to use bronze instead of brass.


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## Harold_V (Apr 6, 2012)

I'd have to agree that the common pin isn't bronze. While I didn't accept escrap for refining, I ran my share through the years, in particular when it was available to me and was run strictly for my own benefit. Judging from my experience, they were made of yellow brass, which, when cut, often is mistaken for gold, through and through. The largest batch I ever processed was 180 pounds of material from wire wrap pin production. I stripped those with cyanide, and sold the remains as scrap brass. 

Harold


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## dtectr (Apr 12, 2012)

Geo said:


> i never heard of bronze being used to make connector pins. normally its either copper or brass. bronze is more corrosive resistant than brass, but thats why they coat them in gold. im not saying its not bronze, just that i dont think it would make much sense for them to use bronze instead of brass.


Then Geo, I suggest you learn to use either the "SEARCH" button or Google (That's where I found this document over a year ago ) and posted it here : http://goldrefiningforum.com/phpBB3/download/file.php?id=9036 .
Do a search for "phosphor bronze" while you're at it. You'll (hopefully) find that it is the alloy of choice when repeated insertions and removals (don't say it, Frank! Lol) are expected, as in backplanes and other edge connector applications. Brass is harder, but more brittle than bronze. The phosphor is for fluidity of the molten metal, if I recall correctly. 
And just because the scrap man PAYS you for "brass" doesn't mean it IS "brass". Honestly, I wouldn't trust my previous one to differentiate between brass and gold, especially when its close to quitting time. 
Now that we can put the posturing aside, can we begin giving TRUE, as well as ACCURATE info to questions? If you process most edge connectors, at least the older, profitable ones in nitric, especially if heat is involved, you will likely encounter METASTANNIC ACID, in addition to more run of the mill issues.


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## Geo (Apr 12, 2012)

dtectr, i certainly didnt mean to offend you. if i did i apologize. i said i had never heard of it, and now i have. i did a series of searches to try and enlighten myself. the pins that are bronze is in specific applications but theres no way to visually detect from one pin to another whats what if they are already removed from the connector.theres a good chance that in any amount of pins there will be bronze pins in the lot. you may be able to separate the types while they are still in the plastic connector, but thats seems like a lot of trouble unless you can identify without doing a search for each one.its easier to assume that theres some of these pins in every batch that you do.

thank you for the information.


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## dtectr (Apr 12, 2012)

Geo
You're right - I did take offense at the continued refusal of many on this forum to ignore facts if they haven't personally encountered them - in this case, tin content of base metal solutions. 
The problem is, I took it out on you, and for that I apologize. 
This is a bigger deal than many will acknowledge - if a novice encounters it and follows only the "expert" advice offered on this issue, he will never achieve complete or satisfactory extraction of values. If you have a variety of feedstock, no problem. If these are all you have, then what? 
Hoke, a genius on all else was off on metastannic acid. 
Sorry to make it personal.


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## Barren Realms 007 (Apr 12, 2012)

dtectr said:


> Geo said:
> 
> 
> > i never heard of bronze being used to make connector pins. normally its either copper or brass. bronze is more corrosive resistant than brass, but thats why they coat them in gold. im not saying its not bronze, just that i dont think it would make much sense for them to use bronze instead of brass.
> ...



Damn party pooper..... :lol: 

See this is where I need my ROFLMAO thread back ( just kidding Harold 8) ).



> This is a bigger deal than many will acknowledge - if a novice encounters it and follows only the "expert" advice offered on this issue, he will never achieve complete or satisfactory extraction of values. If you have a variety of feedstock, no problem. If these are all you have, then what?



Big understatement.


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## gold4mike (Apr 16, 2012)

I'm in the middle of processing many pounds of good quality pins and have been careful to pre-process those with solder to eliminate as much tin as possible before dissolving them in poorman's nitric. 

Those that have no solder showing have gone straight into the nitric. I'm finding that there is a significant amount of tin showing up in my filters even with the extra care I've taken. I am convinced that there is tin in some of them since I'm running some pins that have never been soldered.

I have four buckets with colanders and coffee filters running 24/7 so the slow filtering isn't a problem. I'll incinerate the filters when this large run is done and then use HCl to remove the leftover base metals.

Using the cell wasn't desirable to me for these pins since they're not mine and removing ALL of the gold sludge from the cell is cumbersome at best.


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## NobleMetalWorks (Apr 16, 2012)

dtectr said:


> For the risk harold stated, I would use PoorMan's AR, using INCREMENTAL additions of your nitrate of choice - I use potassium, myself. FWIW



The more base metals you can dissolve BEFORE you use AR, the better off you are, always. AR is used to refine, and only in a few cases should it be used to recover. You COULD use AR, but you would be wasting Nitric Acid/HCl if you are not using Poor Man's AR, and with Poor Man's AR you would be wasting Sodium Nitrate and HCL. 

I am using a sulfuric cell, if you have a lot of pins it can take awhile, using one cell, to process them all. I am doing 1/2 lb at a time so that my volt/amp draw isn't so much that it blows the fuse. I also make a nice ice bed for the Sulfuric Cell in a larger Pyrex dish. Keeping the Sulfuric Cell cold should keep most of the metals that were not used as plating, from reacting and also being stripped. When you see the amp meter read down to or close to zero, you are probably finished deplating the gold.

I have tried using HCl on a small amount of pins, thinking I could dissolve base metals (they are what I call 50/50 pins, they came out of old tub amp connectors and seem to be made mostly of silver/gold) It didn't work because these particular pins have a fair amount of silver, and since silver has a lot higher reduction potential than hydrogen gas, it doesn't work. Sulfuric and Nitric Acid will dissolve silver. 

My point is, if you are not sure what metals the pins are composed of, you might want to test small amounts first. After a test you will better understand which process to use. This is exactly the point I try to make about all in one systems compared to processes. You can be dynamic enough to see the reaction and know if you want to process your material that way, or a different way. With a system that does all this for you, you really don't have a choice.

If you insist on using AR to dissolve your pins, at least give them a nice soak in Nitric Acid before, so that you are not dealing with so much base metal.


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