# AP Gold pin process question



## PARKER113 (Aug 22, 2018)

Hello everyone. 
I'd like to start a new thread called AP Gold Pin Process question. 
I've only started reining on a small scale for a few months. I have done a few small batches of low grade (25 grams), medium grade (35 grams) and my last batch, high grade gold pins (60 grams) All mixed non magnetic.

The first few batches were a bit tedious while separating the foils from the pins. 
The base metals would dissolve about 50% and 85% of the pins would be stripped.
I would pour off as much as I could through a filter which emptied into a used AP jug, then I would transfer the filter to a water rinsing container and spray the gold pin bearing container through the filter. 

But as you guys probably already know it's tough to separate gold foils from small dissolving pins. And adding water to these pins only created white crystals which dissolved with a bit of hcl. Since I have a few 1 liter jugs of used AP I now use them to add more liquid to the high grade pin container to decant. I now swish it around and decant into the foil beaker. And do that a few times until the majority of the foils are out.
Then added more Hcl to dissolve the remaining foils. A few days later when 99% of the base metals from the pins dissolved I decanted and picked out the 3 or 4 small pins that didn't dissolve.

With the last batch of high grade gold pins (60 grams, non magnetic mixed pins) I just let them sit for a few extra days until 99% of the pins had dissolved. (4 days in total)
I didn't filter any of the solution, after reading more on here I thought it wise to only use the filter once after dissolving the gold. 
I ended up decanting the pin bath several times into my 1000 ml beaker, using the used AP solution and then sprayed out the container with water into the same beaker. 
After waiting a day I still see lots of gold floating through out the solution. Could you guys suggest a way for the gold to settle?
And if my procedures were incorrect and inefficient please do shine some light.
I plan on dissolving the foils in this beaker and dropping the gold with Smb. Saving the powder until I find the means to melt efficiently.

Ps. I bought this beaker at a brewery supply store for $17. It doesn't say Pyrex, or anything to do with heat. Is anyone familiar with this beaker, and it's it safe to boil with?

Thanks!
Peter


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## goldsilverpro (Aug 22, 2018)

Beaker
https://www.veegee.com/products/glassware/beakers/20229-50-vee-gee-50-ml-beaker-847.html

Erlenmeyer flask
https://www.veegee.com/20231-1000-vee-gee-1000-ml-erlenmeyer-flask.html


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## PARKER113 (Aug 22, 2018)

Sheesh, that was of course a few clicks for me to find myself. Thank you for finding that! Looks to be just as good if not better (cheaper) than Pyrex. I'll see what I can do about getting a few different sizes of this type.


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## UncleBenBen (Aug 22, 2018)

PARKER113 said:


> Could you guys suggest a way for the gold to settle?



Hit the floaters with a mist of water from a spray bottle. If they are still too oily to sink you can dab a tiny amount of dish soap onto the end of a stir stick and just touch it to the surface of the solution. It will lower the surface tension and you should see the foils drop pretty quickly.

A quick incineration prior to processing will burn the ois off the pins and take care of the problem beforehand.



PARKER113 said:


> safe to boil with?



Sure, but keep in mind that with the narrowing neck of the flask that a vigorous or runaway reaction will boil over A LOT faster than it would with a straight sided beaker.


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## goldsilverpro (Aug 22, 2018)

PARKER113 said:


> Sheesh, that was of course a few clicks for me to find myself. Thank you for finding that! Looks to be just as good if not better (cheaper) than Pyrex. I'll see what I can do about getting a few different sizes of this type.



I was showing you those links because what you were calling a beaker was not a beaker. it's an erlenmeyer flask. A beaker is much easier to pour out of (decant) and also much, much easier to remove the solids. The beaker is more general purpose and the flask is good for specific things - it will concentrate the heat better.


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## bigpagoda (Aug 22, 2018)

I never fill my Erlenmeyer more than 1/4 full. Beakers are also easier to clean. Unclebenben's drop of soap and a spray bottle works for me.


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## PARKER113 (Aug 23, 2018)

Thanks for the reply guys.
Hehe I did not know the difference between a beaker and Erlenmeyer flask. It makes a lot of sense to use a beaker for the majority of the e scrap process. I need to modify my glass stir sticks so they don't damage the glass. Rubber tubing from aquarium pump I'm thinking. 

As far as the gold settling. Thank you for your suggestions. But the fine gold seems the same weight as the solution almost. As in a small amount of foils are suspended all the way up. It's now been about two days. Is possible the solution has too many metals?

Also I have no means as of yet to incinerate.. Unless I can make something with some basic ingenuity. What I did with the last batch of pins wash wash them in 70% alcohol. Hoping that would remove the majority of grime.

Thanks!

Peter


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## UncleBenBen (Aug 23, 2018)

PARKER113 said:


> small amount of foils are suspended all the way up.



I see. Floating in, not on. Then yes, your solution is getting saturated. Good chance there is some tin gelling it up a bit. Hard to completely avoid when dissolving whole pins. If a drop of water creates a white cloud of 
copper(I)chloride, it's saturated with copper and time to decant and replace the acid. Filter to catch the floating foils. Save them to add with the majority of foils when you get done dissolving all the pins.

The alcohol wash will help. By incinerate I mean just put the pins in an old skillet and play a light flame from a propane torch over them to burn off organics. (Never use the skillet for food again!)

Good luck, Peter. Stay safe.


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## FrugalRefiner (Aug 23, 2018)

UncleBenBen said:


> By incinerate I mean just put the pins in an old skillet and play a light flame from a propane torch over them to burn off organics. (Never use the skillet for food again!)


As Ben said. I like a stainless steel skillet/fry pan. You can pick one up at the Goodwill/St. Vincent DePaul/second hand store for a few dollars. In a perfect world, you can put it on an old propane burner like the ones used as a side burner on a lot of propane grills. Get it well heated, then play a torch over the top. You don't want it so hot that things melt, just a dull red heat to burn off all the organics.

Dave


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## PARKER113 (Aug 23, 2018)

Hi Dave, 
I have a large stainless steel shallow skillet that would work wonderfully. I don't have a barbeque but if I layer the pins thin enough on the skillet the flame should incinerate the majority of the organics. Then maybe shake it up and go over it again.

Thanks for your input!

Peter


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## FrugalRefiner (Aug 23, 2018)

That will work.

I'm a charcoal man myself. Never used a propane grill to cook food. But since I've been refining, I've acquired a couple. People throw them away or give them away all the time, often for minor problems. The side burners on the ones I've gotten have always worked. It's a frugal way to get a propane burner. 8) 

Dave


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## acpeacemaker (Aug 23, 2018)

When I was doing foils I would use a charmin plug to get the floaties. I know a drop of dish soap has been recommended a lot through the forum. But if you dont ridden the foils later on of excess soap. You can make some foam or potential boil over with sparkles.

If you dont have a grill or even a cheap torch. I got a small toaster oven as a burnout oven, for $5 at a goodwill. Wal-Mart, Kmart, Goodwill, and other places with baking stuff had mini stoneware breadloaf pans. Only $3....They work really well and slicker than snot. Good for incinerating powders too.

Andrew


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## PARKER113 (Aug 26, 2018)

Thanks for the recommendation guys! I do have a max pro torch so that should work. Also I have a decent electric burner. 
New person question probably.. I finally got the TIN II (100 grams)stannous chloride from the chemical supply store $140.00 with the hazardous handing charge.. I'll attach a pic. But how do I make the test solution? I added about a gram of it to some hcl and dissolved it. Tested it on some gold solutions and it didn't react. After further reading.. Do I need to add tin pieces and distilled water aswell?

Thanks,

Peter


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## FrugalRefiner (Aug 26, 2018)

Yes, you should add some distilled water. Lou suggested 1 gram SnCl2 dihydrate, 5 ml HCl, and 20 ml distilled water. Add some metallic tin to keep the solution in good condition.

That's a crazy price for stannous chloride.

Dave


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## PARKER113 (Aug 27, 2018)

Thanks Dave!


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## nickvc (Aug 27, 2018)

FrugalRefiner said:


> Yes, you should add some distilled water. Lou suggested 1 gram SnCl2 dihydrate, 5 ml HCl, and 20 ml distilled water. Add some metallic tin to keep the solution in good condition.
> 
> That's a crazy price for stannous chloride.
> 
> Dave



Agreed the money would have been better spent buying some decent glassware, he could have got some tin solder or fishing sinkers for a few dollars and made his own :shock:


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## goldsilverpro (Aug 27, 2018)

https://www.ebay.com/itm/Stannous-Chloride-Anhydrous-99-8-1-4-lb/312222149574?hash=item48b1e3ebc6:g:VRcAAOxyoahSWxR~

I think this is the guy I bought from the last time. About $20 including shipping for 113g


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## g_axelsson (Aug 28, 2018)

The price is probably due to "Certified ACS suitable for mercury determination".

Interesting note, it also says "Will absorb oxygen from the air, and convert to the insoluble oxychloride. Keep tightly closed."
This is what happens in solution too when stannous goes bad.

Göran


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## PARKER113 (Aug 29, 2018)

Thanks for the insight guys. 
I did invest in a few more good glassware items a few days ago so I'm pretty happy about that! Also bought a corningware piece that had held up to the element quite well. 
I tested it with water first and wasn't able to bring it to a boil with the set up I have. Not that I'm looking to boil, but I don't know if I'm getting the high temperature I need to wash the gold. Bubbles appear at the bottom and come up well. The solution is hot. (I think it's due to the sand I'm using) gold mining sand still.
I ended up dissolving the foils I got from my 60 grams of high grade pins a few days ago with bleach and let it sit for a day. 
Then used my element to heat up the solution to better drop the gold. The first time I tried nothing was dropping (It's 10 degrees Celsius) outside. So I heated it up and it worked well. Maybe a gram or so of gold.

Well I'll never buy the stannous chloride for that much again! Way to expensive. Should last a few years though.


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## PARKER113 (Aug 29, 2018)

g_axelsson said:


> The price is probably due to "Certified ACS suitable for mercury determination".
> 
> Interesting note, it also says "Will absorb oxygen from the air, and convert to the insoluble oxychloride. Keep tightly closed."
> This is what happens in solution too when stannous goes bad.
> ...



Would putting in an oxygen absorber be useful?


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## Shark (Aug 29, 2018)

As long as I am using an electric hot plate AND corning ware AND good lab glassware, I don't use sand. Corningware made some very tough stuff just be sure it is the correctly rated stuff. There is a thread on the forum all about it and well worth the read. I have used a propane stove and heated some of mine hot enough to see the red glow in full daylight, something that you don't need, but was good to know. I am not sure how many I have, but I use different types for different processes so have several pieces comes in handy.


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## PARKER113 (Aug 29, 2018)

I tested the solution today and it came off as light brown I believe. Is that positive for Au or Pt?


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## PARKER113 (Aug 29, 2018)

Thanks Shark! That's good to know. Maybe I'll lay off with the sand after I determine the corning ware is good quality. Red hot hey? Wow that's some strong stuff!

Regards,

Peter


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## 4metals (Aug 29, 2018)

Did that color show up immediately or develop after you added the stannous? I would say the red color would be Platinum except for the fact that pins are rarely if ever Platinum plated. 

Do you have a prepared positive gold acid standard that is about 5 ppm? If so what does that stain look like? Whatever the stain is, it isn't much!

As far as prices for a limited quantity of refining related supplies, check out Carolina Biological Supply. They are, for the most part, dealing with schools who don't pay the crazy prices Fischer Scientific charges.


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## PARKER113 (Aug 29, 2018)

4metals said:


> Did that color show up immediately or develop after you added the stannous? I would say the red color would be Platinum except for the fact that pins are rarely if ever Platinum plated.
> 
> Do you have a prepared positive gold acid standard that is about 5 ppm? If so what does that stain look like? Whatever the stain is, it isn't much!



Yes the color showed up right away! I tested a few other used AP solutions and my last AR liquid and they all turned clear. Meaning no metals I suppose. 

I do not have a gold solution to test it with. But I will get on that pronto. I have a few 999 bars. .5 of a gram haha.

Thanks!

Peter


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## PARKER113 (Aug 29, 2018)

Here's a picture earlier this evening of the all of the gold that settled overnight. I noticed some darker, finer precipitate. I believe I read on here it's either dirtier gold, or base metals dropped from too much Smb. I'll have to re dissolve, and melt it next spring. As this is it for now with refining. I'll be indoors working on the recovery side!


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## 4metals (Aug 29, 2018)

It is always good to have a positive gold standard for gold to test your stannous. 5 ppm is a dilute standard which is 5 milligrams of gold in 1000 ml of solution. At today's prices that is about 19¢ per liter. But a dilute standard will show you the sensitivity of the stannous test solution.

To put that more into perspective, if you dissolved 7.5 ounces of 14k plumb jewelry it would take about 1 liter of aqua regia. After filtering and rinsing it will be about 1.5 liters awaiting precipitation. If you use 1 drop off the end of a glass rod to drip on a paper towel for a stannous test, that drop contains 17¢ worth of gold at $1200 gold. Pretty pricey drip!


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