Magnesium advice?

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My friend came across some magnesium floats the other day and I have some questions and concerns.

Having heard things about Magnesium we broke off a chunk and I started heating it with his brazing torch. It let off a ton of smoke but I was only wearing brazing goggles because of the light and breathed in a good bit of it. My throat was irritated after that so I ripped up an extra shirt wide enough to cover my nose and mouth, wet the part over my mouth and nose, and we kept on burning chunks until one float was gone. Looking around online just now I think I might have metal fume fever. I have a dry throat, my voice is hoarse, and I have a headache. Could I make a better filter somehow, or is magnesium smoke more dangerous then I think.

The other question I have is about the reaction. While I was heating it I was only able to get two of the pieces to react very violently; burning very fast, very bright, and emitting a lot of smoke (Going right into my face of course but that's beside the point). Those pieces were about as big as a credit card, but when I tried much much bigger pieces, a tad longer and as wide as an iphone, I couldn't get the same reaction. It still would burn brightly and have smaller reactions, but nothing compared to the large reactions. When I got it to react violenty I heated a good 1/2 of it until it was close to liquid, then focused on one part until it went, but when I tried the same thing on another piece the same size it didnt work. The only thing I could think of that would be different each time would be the heat, but the first ones I didn't completely max it out, whereas on the bigger ones I did. Does anyone have any advice?
 
I guess my main question is, what are you hoping to achieve with this magnesium? if its just a big reaction, why not try heating up some battery acid (not clever) and pour it of a slab of hot magnesium. My chemistry knowledge is poor but I can imagine you want to stand well back from that one.

So yeh, my main question is why are you heating magnesium?
 
I'm heating it to get it to react. Just like magnesium ribbons over a Bunsen burner, but on a much much larger scale. Like I said before when you heat it it catches on fire and emits a very bright white light, and two of the times we did it it reacted very violently and lasted for only a few seconds. Basically I want to try and make it react violently again, but I didn't know if anyone had any advice on the technique of how to do it. Apparently it reacts violently with water when it's on fire so I think I might try that, just stand very far away.

I'm going to be trying it again later on tonight and I'll see how it goes. My friend took a video of one of the reactions so whenever we have time to mess around with video we'll get one up on youtube.
 
It's probably a matter of surface area.
A piece of magnesium ribbon has only a small mass, but a huge surface area comparative to that mass. There's plenty of active sites for the oxidation reaction (that's what is happening when it burns) to take place.

With a large chunk there's greater mass and a small surface area relative to the mass. As oxidation occurs the heat is dissipated into the mass and hence the activation energy for reaction is not maintained as effectively.

This is why powders can be dangerous. A powder has a huge surface area to mass ratio, and hence they ignite very easily and will maintain a reaction (very violently in some cases with even the most innocuous of substances, e.g. why there have been explosions at Custard Powder factories.)

Basically the smaller the pieces you can cut your magnesium into, the better it will react, however, I wouldn't recommend doing it anyway, you get a very hot bright flame which is damaging to the eyes if not viewed through a protective shield. :ouch:
 
You reckon brazing goggles are enough? I thought I heard a teacher say it emits radiation damaging to the eyes, or is it just one of things like welding where it's too bright to look at without damaging your eyes without a shield.
 
The reason it is damaging is because of the rays its emitting. It's not the "light" that's hurting your eyes, it's the stuff you can't see, like UV rays and whatnot.
 
The smoke you created would be white magnesium oxide powder. Any kind of mouth and nose covering will be sufficient. Breathing it in just this once won't have done you any permanent damage, but don't do it again. Magnesium, when burned, emits a very bright white flame which can permanently damage your retina - anything which filters this out (polarising sunglasses would do, but I'd recommend a 5mm chunk of blue plastic. If all else fails, the plastic of a CD will do the trick)

Which brings me onto the next question... why were you fannying about with it without any protective gear in the first place? The questions you're asking now are questions you should have asked before you started breaking out the blowtorch...



Incidentally, my recommendation is to get lots of small chunks, heat them indirectly (no flames) until they glow and then plunge them into an oxygen-rich atmosphere (a jar containing 100% oxygen will do it).
 
Famine
Which brings me onto the next question... why were you fannying about with it without any protective gear in the first place? The questions you're asking now are questions you should have asked before you started breaking out the blowtorch...
Click to expand...

I don't really know actually, it's kinda just how we do things. We knew it was dangerous but it was just a spur of the moment type of thing. Stupid I know, but whatever.

Thanks for the advice though, I'll have to look far more into magnesium to make sure I don't kill or hurt myself.
 

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