Hi, everyone welcome back to Cody's Lab so today. I'm going to be trying to extract platinum from spark plugs
I have a whole bunch of spark plugs here that I've collected from junkyards that I've been going to
you see spark plugs are laying around the junkyard all the time because people take them out of the engine block to look inside the
Cylinder to see how well the engine was running and see the condition of the engine block is before
they purchase it and usually the spark plugs end up on the ground and
Eventually they would just get thrown away
So while I'm walking around the junkyard I occasionally pick up a few so I've sorted the spark plugs that I've kept into three main
categories
These over here
Actually say platinum on them these here say
Iridium and
These over here
Don't actually say any precious metal if you look closely at the tip it actually looks like it does contain some sort of precious metal
there, so I still might be able to recover something from it my guess is these could actually be palladium
or they're just unmarked platinum the ones that just had the copper are just still sitting at the junkyard
so to get the platinum out of these I'm going to start by
cutting off
This little thing here
Just like that now this actually contains a little spot of platinum on it as well. I think
Yes, so I will keep keeping that and also this other contact
down in here
There it is
Keeping that as well those are the parts that are going to contain the platinum the rest of this is
Just is really just steel and ceramic the reason that we use platinum in the spark plugs is simply because platinum is a very
resistant Metal
Copper would actually be worn away over time by the sparks as the Sparks are
extremely hot plasma and actually eat away at the metal because it's
basically
Vaporizes it when it touches it the copper will handle it for a while
maybe after a few tens of thousands of miles the platinum can handle the sparks for a very long time before the
Spark Gap actually changes significantly
So long in fact that the platinum Sparkplug is usually outlast the car
see the gap between the positive and negative terminals on the Sparkplug need to be very precise if they're a little bit off the
Spark will either be too small to ignite
the gas
Where the Gap will be too big for the spark to even happen at all if the spark gap is not right the engine won't
run properly
And if your metal is being eroded by the spark then the spark Gap will be constantly changing which is not a good thing to
Have happen
so here's all the little platinum points from
20 or so spark plugs now. I'm just going to put these in acid to dissolve away the base metals
Some nitric acid should make short work of those pieces of metal
But it won't touch the platinum
So while that's dissolving. I think I may as well process these other spark plugs here
and extract the iridium and
Palladium from them so there's the contacts from the iridium spark plugs. I managed to save six of them
I think I started with seven one of them got lost
Here's the ones from the unknown spark plugs now these may contain palladium
so I can't use nitric acid on these I'll have to use hydrochloric acid which will dissolve them much more slowly, but
That will keep the [palladium] from being dissolved by the nitric acid
iridium there are no acids that dissolve it. So I should be able to use the nitric on this just fine. So here
We are after several days in the acid, and I believe I've removed most of the base metals see here's my platinum pieces
Zoom in on these so you can see what shape they're in
There you go. There's some like little pieces of wire, but mostly like these little round
blobs of platinum
And I think there's actually a couple of pieces of stainless steel in there still that was not able to be dissolved by the acid
here's the pieces from the spark plugs that I thought might be
palladium
The acid took a lot longer to dissolve these as I expected in fact a lot of the pieces
I just had to pull out after
The metal fell off of them here of course is the iridium pieces so now I think it's time that I dissolve the platinum
into Aqua Regia, so that I can finish purifying it and
hopefully make some
pure platinum bead that we can weigh
The palladium I'm just going to add some nitric acid to this and see if it actually is palladium
if it is palladium, the nitric acid should
Begin dissolving it almost right away, and if nitric acid doesn't dissolve it then it probably actually is platinum
All right, there's the acid now. I don't see any reaction, but I'll give it a few minutes
So I've given it some time in a bath of hot water
And it doesn't appear like is reacted with it at all
That means I don't actually have palladium here. I think it's kind of weird they wouldn't mark the
Platinum Sparkplugs, I think that would be a selling feature right, but apparently some of them
They don't mark so I'll just mix this in with my platinum
I'm actually going to just mix them all together.
Okay, so I just put in a little bit of hydrochloric acid
Now Aqua Regia get does dissolve platinum, but very slowly at room temperature if I warm it up. I can increase the rate significantly
Looks like the platinum is beginning to dissolve the solution is turning red as the platinum goes into solution. I think that over there
that's bubbling furiously is actually some of the stainless steel that was left
It shouldn't hurt things too bad update number two
it appears that all of the stainless steel is now gone
And you don't see any visible bubbles
that's because the platinum just dissolves so slowly so it's been a little bit more than an hour since my last cut
I put this on there to conserve nitric acid so it didn't all evaporate away
See we got nice Red Liquid
Pretty sure all the- Oh, that's warm, let me get something- pretty sure all of the platinum should be dissolved by now
So let's pour this off
hopefully retain the
Iridium
I'll give this a little bit of rinse later, but yeah, there's the iridium and a little bit of
Probably some metallic oxides. That didn't dissolve. So there's actually quite a few little pieces of metal in there
There's definitely a lot of the platinum ones that are dissolved
But a lot of those that I thought were palladium at first
Must have actually been iridium
Cool. I got more iridium than I thought I would so I put this large bottom dish with the platinum back into the crock-pot
To evaporate it dry. This is to actually get rid of all the nitric acid
Most of it's probably already gone
But let's get rid of it for good now that the platinum solution is completely dried out
I can turn it back into platinum metal. So now I've reconstituted the platinum with some water
To get it dissolve into liquid form again. I'm going to transfer it over into this
Steeper sided container and now to precipitate out the platinum and add in a little bit of
Ammonium chloride which I've dissolved into a little bit of water here
Now I just let the platinum ammonium chloride settle out a solution
Now that I've given it a few minutes to settle out
We should be left with a yellow precipitate on the bottom so the solution here is still a bit orange
now that could be either that it's got a little bit of platinum left in it or
It has something to do with the stainless steel that was dissolving earlier
So here's my platinum ammonium chloride on a piece of paper as I just filtered it out
Now let's put it inside this crucible. I'm going to add a little bit of borax and
A little bit of litharge, or lead oxide if you guys have seen my precious metal refining series
You guys all know that I use this a lot
to collect together the small amount of precious metals into a
Workable Metal bead while that's cooking. Let's see if we can melt down this iridium
I'm gonna have to use a torch to do it because iridium has a very high melting point
Not even sure if I can do it
Well, I actually wasn't able to melt it that iridium is just too hard to melt
Or my torch is just not good enough, so
Here's our crucible with the lead platinum alloy
Let's pour it off
Okay
That looks good
Now to remove the platinum from the lead I'm going to add it to a cupel and put it back in the furnace
Let's see if we got in here
It's warm
There it is
There's our platinum
Now it's not going to be quite done because 2,000 degrees fahrenheit is not hot enough to melt the platinum
so I'm actually going to hit this with a torch real quick to
melt it and that will drive off the rest of the lead and
instead of being a little pile of
Platinum Powder, it should be a solid bead
Well, it's a little bit smaller and a little bit less shiny, but it should be pure platinum now
So here are the iridium wires from the spark plugs. Let's see how much they weigh
set them over here on the scale
Okay, they're going everywhere but they're on the plate
26 Milligrams that's not very much, and it's even less because iridium is incredibly dense. Let's tare this
now I've got my
Platinum bead in these calipers here as you can see it's one and a half millimeters wide
Let's actually put this on the scale
And see what it weighs
There it is
41
40 40 milligrams I was hoping to get a little bit more
But I suppose that is right about 2 milligrams per Sparkplug which seems reasonable
Anyway, hope you all enjoyed. I'll see you next time