Lead (Pb) in Cons

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n2gold
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Lead (Pb) in Cons

Post by n2gold » Sat Dec 07, 2019 12:03 am

Any ideas on the best way to get the lead out of fine concentrates? My cleaned up cons have almost NO black sands, but are contaminated with visible, ugly lead. Even with careful panning, I can't separate the lead from the gold. Everything is classified to the same size all the way down to 40-minus mesh. I'm going to try a blue bowl, but am not holding my breath that that method will work. What about nitric acid? Or any other ideas? Appreciate any tips you folks can give.

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Re: Lead (Pb) in Cons

Post by Jim_Alaska » Sat Dec 07, 2019 12:27 am

The blue Bowl is slow, but would allow you to snuffer out only the gold, leaving the lead.
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Re: Lead (Pb) in Cons

Post by Joe.S.AK » Sat Dec 07, 2019 2:56 am

n2 - there is the "Usual Way" and a "Most Unusual Way" to get rid of Lead (natural Lead or bullet fragments, or maybe even solder pieces) from your final concentrates.

The Usual Way is by careful panning of tightly classified final concentrates. Lead has a Specific Gravity (SG) of a little over 11 (solder is SG 8.4) and that can be used to very carefully separate the Gold (SG of 19) from the Lead or solder by weight - all in a simple pan using just water.

The Most Unusual Way is to take a meticulously clean brass tray / container of some sort and "Tin" a portion of it with solder as you would do in sweating copper plumbing tubing. Then, in very small batches, CAREFULLY heat the lead and Gold, from the underside, under the tinned side, with a small torch. The heated solder "Tinning" under the concentrates melts the lead (or solder) and the liquid metal is selectively picked up by the solder tinning. Do not get excited and blow the Gold everywhere with the Propane Torch! Roll the free Gold onto the other half of the container and remove. Repeat until the contaminating loose Lead is removed.

My personal preference is just separation by panning of the classified, same sized concentrates. For my small quantities of Lead present in my concentrates it is not hard at all. If you are new to panning the process is simply perfected by practice (endless, endless, unending practice!).

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Last edited by Joe.S.AK on Mon Dec 30, 2019 6:00 am, edited 3 times in total.
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Re: Lead (Pb) in Cons

Post by Joe.S.AK » Wed Dec 25, 2019 5:06 am

Jim_Alaska wrote:
Sat Dec 07, 2019 12:27 am
The blue Bowl is slow, but would allow you to snuffer out only the gold, leaving the lead.
Jim,

Something to think about - from the beach at Nome:

The beaches around Nome were covered with miners around 1900. "Tin Cans" in that time era were soldered shut (while very hot) to allow the sterilized (usually) boiling hot contents to form a vacuum when the contents cooled. Empty cans were discarded on the beaches and after 100+ years the Tin and Steel were eaten away by the salt water. The untouched solder remained on/in the beach sand and was "recovered" in the Beach Box's concentrates.

In panning the relatively prolific, yet extremely small Gold, it just became really burdensome to pan and tap, pan and tap, pan and tap "full" pans of concentrates over and over again until they were "clean" --- and then do it all over again! It took hours!

A technique was discovered which sped up the process.

Pan and tap a little of the concentrates down to a small "golden smile" and sucker-up only the highest percentage gold first. Then take a separate sucker bottle and sucker-up as much of the pure black sand as practical from the other edge of the pan. Repeat the Pan, tap and sucker bottle technique once more and then add a little more concentrate to the pan and do it all over again.

At the end, save all the suckered-up black sands and re-run them through the equipment the next morning to catch any escaped gold from the black sands.

The solder was relatively easy to separate out by weight and so the process was even faster (yet still exhausting!)

Oh, how did I know that the cans were the source of the solder? The solder was used to seal all around the bottom of the can to the side first. The can was filled with food and fluid to the top and then a top lid ** with a small hole in it** was also soldered all around. The cans were then boiled (or baked) until heat sterilized the food, removed from the oven and immediately had the small hole closed with solder and a metal disc. Where the sides met the top or bottom lid the solder formed a uniform, inside, curve, matching the diameter of the can while the cross section of the curved solder was triangular. Small triangular bits of solder were a real challenge to pan out of the concentrates.

Worked - sorta - except that lead poisoning from the solder (among the old timers) was a real problem.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1279489/

oh, n2 - Nitric won't work but heating the bottom of a tinned brass "pan" might just do OK. Be sure to not breath any of those lead fumes - do things with lots of air flow away from you.

Joe
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Re: Lead (Pb) in Cons

Post by LipCa » Thu Jan 02, 2020 2:22 am

I might as well be the first to post in 2020!
Depending where your cons came from and what they look like, you might have platinum, not lead??
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Re: Lead (Pb) in Cons

Post by Joe.S.AK » Thu Jan 02, 2020 7:33 am

Excellent thought, Harry!

If it's Platinum then it would take a LOT of heat to melt it - 1772 degrees C. (3,132.6 F.), while Lead melts @ 328 C. (621 F.). Pretty easy to see - say holding it with tweezers, needle nosed pliers or something similar - if it took a lot of heat or not so much heat to melt a single piece sample of the non-Gold material.

Also, lead is very soft and malleable while Platinum is exactly the opposite.

So, soft and it crushes or scratches easily, is noticeably lighter in the pan or melts at low flame temperature would pretty much be a dead give-away as being Lead. I would classify to nearly the same sized particle size and pan it.

Joe
Last edited by Joe.S.AK on Fri Jan 03, 2020 6:01 pm, edited 1 time in total.
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Re: Lead (Pb) in Cons

Post by LipCa » Fri Jan 03, 2020 5:00 pm

Since Platinum is slightly heavier than gold, it's going to hang right there with gold. Making it hard to separate.
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