# Pins in A/P



## rewalston (May 25, 2014)

I'm going to be doing a crockpot AP later this week on some pins I have. I'm not expecting much, but any is better than none. Would it be a good idea to incinerate the pins before putting them into AP?

Rusty


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## Smack (May 25, 2014)

It sure couldn't hurt.


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## Geo (May 26, 2014)

Unless the pins are oily or trapped in plastic, I don't really see a need to incinerate. If the pins were soldered, you may run them through a hcl bath first to remove as much tin as possible. When you incinerate things like pins, the gold shell cracks along weak points from the thermal expansion and contraction. Don't incinerate and wait to process because the gold will start flaking off almost as soon as the metal cools.


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## rewalston (May 26, 2014)

Thanks guys, I've got a few pins with just a speck of plastic, but with the amount there it shouldn't be a problem. I'll just crockpot everything with some AP and let it run. I've got a few more pins to recover from some dips witches (those are where the plastic is from). I'll post a picture once I get it "rolling". Thanks again.

Rusty


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## Pantherlikher (May 26, 2014)

Warm HCL to make sure there is no solder. Then AP with an air pump and time will work great.
Certain plastics can be a problem which will be extracted and incinerated. Some soften to a thick mush and is tough to work with.

To prolong you solution, you may want to take out the magnetics as that will fowl when enough builds up. Allot that is. I ran a bunch through mine and the only reason I treated mine as waste was because winter was coming. Anything magnetic can go into your waste pot where it will remove everything but PMs, copper and maybe tiny amounts of base metals.
Again, this depends on how much you intend on putting into the AP soak.

B.S.


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## rewalston (May 26, 2014)

I'm running about a pound of pins.

Rusty


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## rewalston (May 28, 2014)

Well, I ran all my pins for 2 days on high in the crockpot, still a lot of copper undissolved, and a lot of gold flakes. I'm assuming that I'm going to need to dissolve all the copper before I can do anything with the gold. I moved the solution to a bucket with my air pump. And added about two more cups of HCl.

Rusty


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## Geo (May 28, 2014)

If you force a volume of solution to dissolve more copper than it can hold (sounds impossible but it happens all the time) the copper metal will continue to dissolve but copper(I) chloride will precipitate out. It will look like cloudy green mud. If this happens, add fresh hcl and the solution will turn deep emerald green and go clear.


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## rewalston (May 28, 2014)

Geo said:


> If you force a volume of solution to dissolve more copper than it can hold (sounds impossible but it happens all the time) the copper metal will continue to dissolve but copper(I) chloride will precipitate out. It will look like cloudy green mud. If this happens, add fresh hcl and the solution will turn deep emerald green and go clear.



Yep it went clear. I have a bubbler in the bucket now and it's more of a greyish clear blue instead of green. Still have a lot of undissolved copper and lots of gold flakes.


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## Geo (May 29, 2014)

The thing about AP that some people overlook commonly is assuming the volume of solution needed to dissolve a certain amount is less than it actually is. I confuse myself when I'm sleepy. Theoretically, One gallon of 32% muriatic acid will dissolve around 2 pounds of copper as copper chloride. So 1 pound of pins should require somewhere around one half gallon muriatic acid as copper chloride. Starting from basic components (hcl,peroxide,etc.) nearly 100% of the acid will be needed in the reaction. Given time needed and evaporation of the solution, any evaporation of the solution below the original amount of concentrated acid and the solution will be losing acid in fumes. Diluting the hcl before starting the process is better than adding water later which will weaken the acid further and make it drop out copper(I) chloride. Also, this just accounts for the copper and nothing else. If the pins have springs or are springy themselves, chances are they will be phosphor bronze which contains tin.


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## rewalston (May 29, 2014)

> Theoretically, One gallon of 32% muriatic acid will dissolve around 2 pounds of copper as copper chloride. So 1 pound of pins should require somewhere around one half gallon muriatic acid as copper chloride.



Geo, that was what I was looking for. I haven't checked the bucket today. How long should it take to dissolve the rest of the copper? Or should I put it back into the crockpot? I have quite a bit of gold flakes and black powder but with the pins still somewhat intact, I have no way to separate the flakes and powder from the pins. They just fall through my colander.


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## maynman1751 (May 29, 2014)

In my own experience, heat definitely accelerates the process.......so I'd say crock pot.


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## rewalston (May 29, 2014)

maynman1751 said:


> In my own experience, heat definitely accelerates the process.......so I'd say crock pot.


Thanks maynman. I'm leaning towards that. I love your sig line...the only thing I would add is "you can't fix stupid...but a 2x4 helps"


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## Geo (May 29, 2014)

If theres gold still on the pins, you will have to finish the dissolution of the pins. If the gold has already come loose from the pins and now you have flakes and bare pins, you can use hcl/Cl to dissolve the loose foils. You will have to work quickly because the base metal will start cementing gold as soon as it goes into solution. With the excess chlorine still in the solution, you will have time to decant the solution from the pins before the gold cements out. If you do it this way, wash the pins twice in hcl/Cl to be sure you got all the foils.


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## rewalston (May 29, 2014)

Thanks Geo, I'm pretty sure that all the gold is off the pins and is either in the form of powder or foils. For a pound of pins how much HCl/Cl would you recommend?


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## Geo (May 29, 2014)

Since nearly all the base metal will be present, do this as quickly and safely as possible.

(1) have all the chemicals poured and handy in separate containers.
(2) add enough hcl to completely cover the pins.
(3) add 10ml's of bleach and swirl for a count of ten.
(4) add 10ml's of bleach and swirl for a count of five and immediately decant solution into an clean vessel leaving the pins behind.
(5) replace fresh hcl and repeat the steps above.

If you can see any foils or black soot when you add clean water to the pins, repeat once more leaving the water on the pins the final time.

If the pins were a good quality, there should around 1g +/- of gold from a pound.


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## dannlee (May 29, 2014)

> when you add clean water to the pins



In your list of steps.. where is water mentioned?

(I just happen to have 120g of nice pins waiting)


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## rewalston (May 29, 2014)

Thanks Geo, I'll let everyone know how I do. I'm not going to hold my breath. I'll be happy with whatever I get, it's all a learning experience and that experience is priceless.

Rusty


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## Geo (May 29, 2014)

dannlee said:


> > when you add clean water to the pins
> 
> 
> 
> ...



Water is not in the dissolution of the foils but the rinse after.


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## rewalston (May 30, 2014)

I have a quick question. I have some classifiers that fit the top of a 5 gal bucket. I can't remember what size they are, but they are plastic with stainless (I think) mesh. Would AP be a problem with these. I figured that I could stack them together (smallest size on bottom and larger on top) and take my pins that I've been working with and put them on the top screen and this should allow the sediment and foils wash through. Rather than washing them with HCl/Cl to dissolve the foils mixed with the pins.

Rusty


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## Geo (May 30, 2014)

rewalston said:


> I have a quick question. I have some classifiers that fit the top of a 5 gal bucket. I can't remember what size they are, but they are plastic with stainless (I think) mesh. Would AP be a problem with these. I figured that I could stack them together (smallest size on bottom and larger on top) and take my pins that I've been working with and put them on the top screen and this should allow the sediment and foils wash through. Rather than washing them with HCl/Cl to dissolve the foils mixed with the pins.
> 
> Rusty



Stainless steel is dissolved by AP with no problem. You would have to break the foils up small enough to fit through a strainer that the pins wont fit through. Maybe with enough agitation, the foils will break up fine enough to classify.


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## rewalston (May 30, 2014)

Geo said:


> rewalston said:
> 
> 
> > I have a quick question. I have some classifiers that fit the top of a 5 gal bucket. I can't remember what size they are, but they are plastic with stainless (I think) mesh. Would AP be a problem with these. I figured that I could stack them together (smallest size on bottom and larger on top) and take my pins that I've been working with and put them on the top screen and this should allow the sediment and foils wash through. Rather than washing them with HCl/Cl to dissolve the foils mixed with the pins.
> ...


 I don't want the stainless to dissolve :lol: I think that the size of the foils I have should wash through fine. I'm just a little nervous about adding HCl/Cl to the pins. I have some filters that I'm going to do as well (separately). Just trying to figure out an easier way to filter the pins and separate them from the foils and powder.


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## glondor (May 30, 2014)

Just a curious question, If GEO's method works, why bother with AP at all? Have you tried stripping pins with just hcl/ bleach? Might be worth a try.


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## rewalston (May 30, 2014)

glondor said:


> Just a curious question, If GEO's method works, why bother with AP at all? Have you tried stripping pins with just hcl/ bleach? Might be worth a try.


Hey Glondor, no I haven't tried it yet. I have been running just over a pound of pins for about a week in AP. I believe that all gold has been reduced either to foils or black precipitation. No gold is in solution. I was trying to figure out how to separate the gold from the pins as they have not fully dissolved. As I said, no gold in solution so all that is left is the copper pins. I don't have a way unless the screens I have will work, to separate the two factions. I'm going to try them this weekend. They are still bubbling away nicely in AP.

Rusty


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## Geo (May 30, 2014)

Mike, if the foils are still attached to the pins, it will not dissolve fast enough to stop the gold from cementing out.

I wouldn't try to use hcl/Cl just to strip the gold off of pins but since the gold is loose from the base metal and there is excess oxidizer, the gold should stay in solution long enough to just decant to another vessel. Loose foils will dissolve fast enough to accomplish this task. I don't do something like this all the time but just to fix a problem or straighten up a mistake.

Ideally, you would replace the pins and chemicals and finish the dissolution of the pins. The process I described is just something to roughly and quickly recover the gold that's loose from the pins. After doing this for awhile, you will learn that some of the things we are told not to do is because we don't know enough about it to make it work, not because it wont work.


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## glondor (May 30, 2014)

That Is what I thought. Thanks GEO.


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## johnny309 (Jun 1, 2014)

Plated gold on stainless steel with HCl/NaOCl...is the way to try....especially for the time...I mean...not so much gold ,but fast time of recovery.......

And it is only gold(if you are fast...)....nu "base" metals involved.


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## rewalston (Jun 1, 2014)

Just a follow up, I've got everything filtered. I used a mesh classifier that I have to separate out the gold/dust from the pins. All of the gold and precipitation (black dust) are in filters. I'm going to do a rough HCl/Cl to put it all into solution. Then I'll drop, do the washes and do the whole thing all over again. I don't have a lot but it's a start. Never doing pins again. I'll stick to chips and fingers from now on. The pins kept the wife happy but what a pain. I have about 2 pounds of chips and N/S to incinerate. Might incinerate them and the filters first. I haven't decided yet.

Rusty


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