Hey guys my name is Jason with Mount Baker Mining and Metals, and this is video
part two of our lead recovery from our old Portland cement cupels. And I've
got our lead blocks here, we're gonna melt these guys down today and cupel them
again in some real bone ash cupels and see if we can recover any more gold and
silver out. So the first step here is to get our lead blocks in this little
crucible here. We're gonna use the same furnace we used for our lead recovery
from the Portland cement here. And once the lead's molten, I'm gonna try and pour
it into a couple different cupels so then we can oxidize the lead and recover
the precious metals. So these guys here are the little cupels we're going to be
using. These are pretty big cupels actually, these can absorb, according to
the manufacturer, over 300 grams of lead I think it's like 350 or 380 grams of lead.
They're made typically out of bone ash and how these work is when the lead becomes
molten and starts to oxidize on the top and the furnace the bone ash cupels
absorb the lead oxide like a sponge but the the metal stays down here in the in
the very bottom and so you're constantly shedding off the lead oxide into the
cupel. And once all the lead is oxidized you'll be left with a little tiny
precious metal bead at the bottom. And we have a bunch of lead so I'm probably
going to use four or five of these. And heat them all at once so we can
drive off the lead and hopefully end up with five little tiny beads of precious
metal.
Here's our lead down in there and it's starting to melt it's melting pretty
quick into our crucible and I have the cupels around the top of the furnace
there and they're just heating up. We'll get him up to maybe three or four
hundred degrees, I wanted to get him warm before I poured the molten lead into him
just so I didn't have any thermal shock and any breakage on the cupels.
All right so they are I got five of them in there, I couldn't fit all seven, but
uh... They're, they're in there. I really don't know what's gonna happen we might
end up with lead all over the bottom of the furnace or might end up with
five little precious metal beads. But we're gonna fire it up here and see how it
goes.
Now what we're seeing here is the lead melts at about 650 degrees Fahrenheit
but the lead oxide doesn't melt until about 1650 degrees Fahrenheit. And so on
these cupels, there's a lead puddle underneath there and now we're just
reaching the temperature where the lead oxide on top is starting to melt and
it's sloughing off and being absorbed by the cupel. Now we've reached the
temperature where the lead oxide is fully melted and has been absorbed into
the cupel. And you can see the little dark kind of bubbles of lead oxide that
are forming on the surface there, and they're just sloughing off, they're
rolling off down, and once they touch the cupel, they become absorbed and that
process continues on until all the lead is oxidized. Our lead buttons are getting
quite a bit smaller now as the lead continually oxidizes and I've kind of
experimented a little bit. I didn't want to get it too hot because in some of my
old readings I've done if you get the temperature really high you're gonna
start losing some precious metals, especially silver. You want to keep the
temperature somewhere between about 1,800 to 2,000 degrees Fahrenheit as
well as keep fresh oxygen flowing to oxidize the lead, and keep the temperature
even throughout the furnace during the process. And as you can see this cupel on
the far right-hand side here is cooler than the rest so it's a little bit hard
to do in a gas combustion furnace.
I tried my best to get one of these beads blinking over as the last little
bit of lead oxidizes. And this bead here it's a little bit hard to tell because
of the heat waves in the furnace but I think it blinks over right about now, and
we're left with our precious metal bead.
And here they are out of the furnace. I actually can't believe how big those
beads are, I thought they'd be tiny little specks. These are the four one, two,
three, four, that ended up oxidizing. The fifth one here that was right
next to the the burner didn't get hot enough to keep the oxide on top melted
so I'll have to do that one and then these other two here that I didn't have
room for. But, man alive, that's a lot of precious metals there that were
recovered from our first cupels. All right here's our seven cupels after they've
all been oxidized, all the leads been oxidized. This one here on the on the end
it fell apart when I grabbed it with my tongs, but the other six stayed intact.
And as you can see we recovered quite a bit more gold and silver. So here's our
seven little beads, and we ended up with 3.15 grams when it was
all said and done. And so I've added our seven little beads I've put, I don't know,
maybe 10 or 15 grams of lead in a cupel. And I'm gonna reuse one that just
came out of the furnace. And this is again literally just pull them all
together as one single bead, and then we can do our analysis on it. Well lookie
there the lids already melting in the (laughs) in the crucible - or in the
cupel, it's still warm enough. Okay there they are all pulled together. And that
cupel broke as well when I got it out.And you can see it's it's totally
saturated, it's that it's gray all the way through whereas this one on the left
still has some of the tan color from the original cupel. So here's all our beads
kind of conglomerated into one and I'll get this set up so we can try and figure
out the the carat of this gold. Tt looks like it adds quite a bit of silver in it
but we'll get an underwater weight and compare it with this weight and we'll
see see what kind of value we have. Okay now this is kind of goofy looking but
I'll tell you what I'm doing here. So we have the little jug of water there and
there's a piece of wire going down into the water. It's not touching
the cup in any way, it's elevated off the bottom, but it's submerged in the water.
We've zeroed the scale, and so we have the weight of the initial button, now we're
gonna weigh the amount of water that the button displaces. So when I when I put
that gold bead on that little loop on the wire, the water level will rise a
little bit and the gold is going to displace the water and we can weigh the
amount of water that we displace and then we can divide the amount of water
weight by the original weight of the button and get a karat value or a
percent gold and silver value. So there's our little gold beads sitting on that
little wire platform and you can see the weight on the scale is 0.23 grams, so
we've displaced 0.23 grams worth of water so now let's do a calculation and
figure out the density of that button. So here's our little calculation, our dry
gold button weighed 3.14 grams the amount of water we displaced was 0.23
grams and so when you divide those two we ended up with 13.65,
which is the density of that bead. So there's a bunch of charts online that
you can look up the density of the bead if it's just gold and silver and it'll
give you the karat gold and I did that online I'll post a link to the website
here in the description. But it came out to be about 13 karat gold which is
roughly about 540 parts gold per thousand. And so when you end up doing
the math on that we ended up getting 1.7 grams of gold and 1.44 grams of silver.
So not too bad out of a bunch of junk I was just gonna throw away. So a couple
more thoughts before I sign off here, I ended up cupelling about I don't know 70
grams or so of gold and all those used cupels we reprocessed and so that ends up
being about two or two-and-a-half percent loss of gold. So we didn't
actually lose that much, but I cupelled a whole bunch in the Portland cement so
that's one of the reasons why we're seeing so much gold end up
here. And another question I'm sure I'm gonna get is can you reuse the lead as a
collector metal again once it's been recovered from the cupels. And you
probably could to a point, but as the base metals start building up in the
lead that you're recovering and reusing, it's gonna get harder and harder to get
a good cupel off your buttons and get clean gold. So because
lead's so cheap, I'd just dump the lead that you recover, recycle it, and get new
lead from fishing weights or roofing or something like that so you're
using fresh lead every time. So hopefully you guys enjoyed the video. If you have
any questions or comments on what you saw today, please let us know. You can
find our contact info in the description below. So thanks for watching and we'll
see on the next one