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How do they melt carbon?

by cragar
Tags: carbon, melt
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cragar
#1
Nov6-09, 12:22 AM
P: 2,466
If carbon has the highest melting point of any of our known elements , then how do they melt it , the only thing I could think of is containing it in a magnetic field and maybe using like an electric arc furnace.
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Pengwuino
#2
Nov6-09, 12:45 AM
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What do you see as the problem?
cragar
#3
Nov6-09, 12:58 AM
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so what container do they put it into , and how do they keep the oxygen away from it .

Pengwuino
#4
Nov6-09, 01:09 AM
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How do they melt carbon?

I can imagine it can be contained in containers that have high melting points due to the alloys used. Though, not my field of expertise!
cragar
#5
Nov6-09, 01:29 AM
P: 2,466
ya i dont know , carbon has a higher melting point then brick and some rocks
which are pretty high .
Borek
#6
Nov6-09, 02:50 AM
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You don't have to use a container. Take a block of substance and heat it in one point at the top - when it starts to melt it doesn't melt in the volume, but just in the place it was heated. This way substance itself works as a container

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cragar
#7
Nov6-09, 04:02 AM
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ok i could see that , how do we keep oxygen away from it so it doesn't burn.
alxm
#8
Nov6-09, 06:05 AM
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Quote Quote by cragar View Post
ok i could see that , how do we keep oxygen away from it so it doesn't burn.
You do it in an oxygen-free environment? That's a pretty easy part.
Borek
#9
Nov6-09, 07:10 AM
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Quote Quote by alxm View Post
You do it in an oxygen-free environment? That's a pretty easy part.
Agreed. Vacuum or inert gas. Both used in commercial applications on the large scale, so no problems with implementation.

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windwitch
#10
Nov10-09, 12:34 PM
P: 18
Different carbon compounds have varying melting points so perhaps you melt carbon by placing a carbon compound in a container comprising carbon compounds with a higher melting point?
SeanB
#11
Nov15-09, 09:59 PM
P: 4
its very simple. you need a controlled environment. remove the O2 and substitute it with an inert gas. bring the environment up to ( ) pressure and introduce an plasma or ( ). why would you want to know this anyway? are you looking for a challenge? NASA Challenge?
cragar
#12
Nov15-09, 10:12 PM
P: 2,466
I was just thinking about it one day , thanks for the answer.
lightarrow
#13
Nov16-09, 01:22 PM
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Quote Quote by cragar View Post
I was just thinking about it one day , thanks for the answer.
Of course you know that carbon doesn't melt at standard pressure, it sublimates.
SeanB
#14
Nov16-09, 04:17 PM
P: 4
The reason I responded to this, this way is because Im in my prototype stage of production. I’ve tested several different theories and im stuck on this one. So we will see. Thanks again and very good question. At least for me.
PhaseShifter
#15
Nov16-09, 04:25 PM
P: 272
Quote Quote by cragar View Post
ok i could see that , how do we keep oxygen away from it so it doesn't burn.
Quote Quote by alxm View Post
You do it in an oxygen-free environment? That's a pretty easy part.
Quote Quote by Borek View Post
Agreed. Vacuum or inert gas. Both used in commercial applications on the large scale, so no problems with implementation.
Considering that carbon sublimes at ambient pressures, I would go with the "inert gas" option.
DrDu
#16
Nov17-09, 02:36 AM
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Would there be really be a difference between vacuum and inert gas atmosphere as far as subliming vs. melting? The relevant pressure seems to me to be the partial pressure of carbon and not that of an inert gas.
PhaseShifter
#17
Nov17-09, 03:49 AM
P: 272
Quote Quote by DrDu View Post
Would there be really be a difference between vacuum and inert gas atmosphere as far as subliming vs. melting? The relevant pressure seems to me to be the partial pressure of carbon and not that of an inert gas.
To some extent you are correct, however, there is the difference between evaporation and boiling--pressure will prevent bubbles from expanding within the liquid.
SeanB
#18
Nov17-09, 10:06 PM
P: 4
Ok. So this is what I did. Pressure is important and so is replacing the “air” with an inert “gas”. Have you ever welded? or brazed?. If not you will have to picture a steel frame which is lined with plexi/glass which is also lined with fire bricks. On the top part you have a regulator which is attached to your inert gas and the bottom part a valve exhaling air which is heavier then your inert gas. You need to do the math... volume in = volume out. Also the specific gravity of your gas and air. Once the air is replaced shut off your volume out and keep your volume in running until you have achieved you desire pressure. You are protecting the carbon and preventing oxidation. With out it carbon explodes or should I say porosityis created. That’s why tig welding mild steel is tough. then melt with plasma or electrical field. This information should not be considered true and unless you are an expert do not try this experiment. All information is considered read only and is not intended for practical use.


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