Warning: This experiment deals with extremely high temperatures, flammable materials and molten metal.
This should be performed outside with appropriate fire safety precautions.
Greetings fellow nerds.
In a previous video I showed various ways for making iron oxide for use in thermite.
In this video weíre going to make thermite and test all the iron oxides we created.
So here we have the various sources of iron oxides.
Starting from the left we have rust that was made from steel wool.
We have wet chemical iron oxide that was made from a solution of iron chloride salts.
And we have electrolytic iron oxide that was made by electrolysis of iron nails in a salt water solution.
For comparison purposes Iíve also included pottery grade iron oxide that can be easily bought online as a pigment for pottery use.
And i have laboratory grade iron oxide which is extremely pure and used for scientific research.
All of these samples have a mass of 60 grams except for the rust which has a mass of 30 grams.
I have less rust because i didnít make enough.
Anyway, letís get started.
Now in order to make iron oxide and aluminum thermite you need to use one gram of aluminum for every three grams of iron (III) oxide.
You donít need to be extremely precise as thermite is somewhat forgiving of the ratio.
Since i have 30 grams of iron oxide rust here iíll be using 10 grams of aluminum powder.
Let me mix that up.
Now weíll need a container. Obviously a glass beaker will shatter at the extreme heat of the reaction.
So weíll use this clay flower pot which has a convenient drainage hole that weíll drain the molten iron through.
Now we canít have the thermite mixture draining before the reaction even starts so we put in some aluminum foil to block the hole.
The molten iron will then melt through the aluminum foil and drain out.
Okay weíre ready. Obviously iím not going to light this in my fume hood as it will melt right through.
So weíre going to do this outside in a highly sophisticated thermite testing rig.
And this is our highly sophisticated thermite testing rig. (heheheh)
Now to ignite the thermite iím going to use some sparklers that iíve wrapped in magnesium ribbon.
I find this method more reliable than either sparklers or magnesium ribbon alone.
Just insert the magnesium wrapped end into the thermite and light the other end with a torch.
And there it goes.
Only 40 grams total of thermite and it was hot enough to crack the flower pot.
Let me get in closer.
You can see some of the red hot globules of molten iron.
The rest of the iron has drained through the hole.
Weíll let that cool and examine it later.
Here we are a couple of hours later.
You can see here three shiny globules of solidified iron metal.
And on the brick we have the rest of the iron.
Now most of this is actually a slag of aluminum oxide.
So we have to smash out the iron with a hammer and chisel.
A lot of people mistaken the red hot molten liquid as pure iron when theyíre actually looking at the slag.
Okay there we go. And there is our nugget of iron.
We can test it by holding a magnet near it.
Iron has a very strong attraction to a magnet.
The aluminum oxide slag might have a small attraction from tiny amounts of residual iron, but this is very weak.
Alright, letís move on to our next test, wet chemical iron oxide.
Now originally this came in large chunks so i smashed into smaller particles with a hammer.
Itís very important to use as small a particular size as possible to as the more surface area you have, the faster and smoother the reaction.
While it is possible to use larger chunks,
itís extremely difficult to ignite and you usually have to start it with a small batch of fine particle thermite to get it going.
Okay, since i have 60 grams of iron oxide iíll use 20 grams of aluminum this time.
Here we are and iíve already placed and lit the magnesium wrapped sparklers.
Chemically, whatís happening is the iron oxide is reacting with aluminum metal to produce iron metal and aluminum oxide.
In this case the aluminum is the fuel that accepts oxygen and the iron oxide is the oxidizer that provides oxygen.
Ideally the reaction produces no gasses so it canít lose heat that way,
all the heat stays in the products and thus it can become extremely hot.
Aluminum is an extremely energy rich fuel so its oxidation generates a lot of heat.
Combined, these two properties allow thermite to easily reach molten iron temperatures.
Looks like our reaction is completed. We got a very nice formation of molten aluminum oxide and iron.
All of our material has drained through so letís wait for this to cool down before recovering the iron.
Here we are. Looks like it once again destroyed the flower pot.
Let me see if i can break it offÖ oh there we go.
HmmmÖ. looks like iíll have to use the hammer and chisel again to separate the iron and slag.
Okay, letís me start work on it.
The iron, being much denser than the aluminum oxide slag sinks to the bottom while the slag floats on top.
This is actually very useful in the metal industry because the floating slag actually protects the molten iron from being reoxidized by the air.
And here we go, weíve recovered several nuggets of iron from the wet chemical iron oxide.
Theyíre separate nuggets rather than one big nugget because the thermite wasnít hot enough for long enough to have them coalesce.
We also need a better receiving container than this brick but oh well.
Letís move on.
Now weíre going to try electrolytic iron oxide.
Here we are. 60g of electrolytic iron oxide mixed in with 20g of aluminum powder and lit with a magnesium wrapped sparkler.
Aluminum is the fuel of choice for thermite as it produces a lot of heat energy when it reacts with oxygen
and it boils at very high temperature of around 2500 degrees celsius.
By having a high boiling point it can react at high temperature without boiling away and being lost.
Magnesium metal is also very energetic as a fuel but has a boiling point of around 1000 degrees celsius.
So it canít reach a higher temperature without being lost to boiling.
Okay, looks like weíre done.
We have a nice complete reaction with most of the mixture drained out.
And there is our pool of iron and slag.
Once again weíll wait for it to cool and recover our iron.
And here we are. Letís see what we got.
If youíre just after molten iron and less interested in high temperatures.
Then you can spike your thermite mixture with bits of raw iron like nails.
Some of the heat energy will go into melting the raw iron so youíll get more molten iron at a somewhat lower temperature.
Be careful of adding too much iron though or else it wonít melt.
Anyway, here is our recovered iron.
These nuggets appear to be larger and better formed than the impure wet chemical iron oxide i was using.
Okay, letís move on and try pottery grade iron oxide.
This is probably the easiest type of iron oxide to buy.
And there it goes.
Now thermite is not restricted to just iron oxide and aluminum.
You can also use other metal oxides like copper oxide or chromium oxide and obtain copper and chromium respectively.
But be careful, those compositions may burn at faster rates and copper oxide thermites in particular burn with an almost explosive speed.
I donít recommend testing alternative thermites without thorough research beforehand.
Okay, looks like weíre done.
Performs just as well as our other iron oxides.
Alright letís let that cool and hack out our iron.
When making thermite itís important to have dry powders.
So it helps to heat them up to drive off any water.
If theyíre not dry then as the thermite reacts the absorbed moisture quickly converts to steam and can blow apart the thermite,
sending bits of molten metal all around.
Thatís why i have a crude contained testing rig to direct any flying metal away from nearby things i want to protect.
Fortunately, all my thermite was well behaved.
Okay here we are, nice big nuggets of iron.
As you can see the pottery grade iron oxide is pretty good so donít recommend making your own iron oxide if you can easily buy pottery grade iron oxide.
Anyway. Now letís try laboratory grade iron oxide.
Iím using two flower pots to contain the greater heat iím expecting.
And there it goes.
Now in addition to sparklers and magnesium ribbon,
thermite can also be ignited with a mixture of potassium chlorate and sugar, better known as rocket candy.
Iím told that potassium permanganate and glycerine also works but i never tried that one myself to know.
In anycase i still prefer sparklers and magnesium ribbon for their reliability.
Okay looks like this thermite worked very well.
Interesting, it didnít fully react.
I donít think it was because of lower quality, actually i think the opposite happened.
The reaction was so fast that it melted through the aluminum foil and drained out before it could spread to the rest of the mixture.
Nonetheless most of it reacted.
Letís wait for this to cool and recover the iron.
And here we are. We can see a small amount of unreacted thermite.
Despite being an incomplete reaction and having two flower pots, the laboratory grade iron oxide was still hot enough to crack them both.
I donít have enough laboratory grade iron oxide to try again,
but if i did, i would keep the reaction going longer by using an iron sheet to plug the hole in the flower pot rather than aluminum foil.
The iron would take longer to melt and hopefully the reaction would spread throughout the thermite before draining away.
Wow look at that. At least the laboratory grade thermite was hot enough and pure enough to coalesce into one solid piece of iron.
I think Iím going to keep this as souvenir.
Anyway, there you have it. Testing various sources of iron oxide for themite.
They all work reasonably well so use whatever iron oxide is easiest or cheapest for you to obtain.
Thanks for watching.
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