Coal, carbon, charcoal, graphite...

[Externet]

What are the important differences in use interchangeability among coal, carbon, charcoal, graphite ?

As to be used in a battery cell electrode; would a rod made of reasonably pure (~85%) 'natural' coal behave like a carbon rod ?

 

Question 2 : Seen chinese machinery manufacturers advertising extruders to make rods and hollow rods from coal/charcoal. What is the main use for such product ? Is it used in USA ?

 

----> www.alibaba.com/showroom/coal-rods-extruder.html

[John Cuthber]

My best guess is that the coal rods are for fuel rather than anything else. Perhaps as a way of using coal dust which is otherwise a messy nuisance.

 

According to this

http://info.ngwa.org/gwol/pdf/722500216.PDF

(P39) The resistivity of coal varies a lot.

[Enthalpy]

Charcoal and coal are hydrocarbons (with much C and little H) which allows them to burn, as opposed to graphite. Very different. Not interchangeable. Rods of coal can't replace graphite, I expect, and must be a fuel, yes.

 

Charcoal is pyrolysed wood. Coal is extracted in mines and normally pyrolysed before use - names change in this process.

 

Carbon is the element and is also a synonym for graphite, though some people make differences, with graphite being more heavily heat-treated.

 

Fun: nobody knows precisely the properties of graphite, hence carbon, because it's so inconsistent. Different processes (pyrolytic, and so on) make different properties (paramagnetic), and even the same process results in different densities for instance. And it can also be amorphous, vitreous, polycrystalline and the like.

[John Cuthber]

Coal and charcoal are complex mixtures which contain carbon as well as a whole lot of other compounds. (Incidentally, you missed out the nitrogen, sulphur and other things.)

"Charcoal and coal are hydrocarbons (with much C and little H) which allows them to burn, as opposed to graphite."

That's the sort of thinking that gave us this

http://en.wikipedia.org/wiki/Windscale_fire

 

Graphite burns well enough- it's just a bit hard to light.

 

Also, if you roast coal you get coke which is much closer to pure carbon (almost all the O, N, H, and S are removed) but which is still used as fuel.

"Coal is extracted in mines and normally pyrolysed before use"

Not really, most of it is burned. Some is turned to coke, but since the other products i.e. the gas and tar are valuable this process is just as much "using" the coal as setting fire to it.

 

"Carbon is the element and is also a synonym for graphite" and also for diamond and C60

The properties of high purity well ordered graphite are reasonably well known. The properties of mixtures like charcoal are, of course, different and more variable.

[canoncity]

hi- do you know the process to convert hard coal to coke ?

 

would it be like wood to charcoal ?

 

I am looking for the best carbon for G P rockets...

 

I am CANONCITY

[Enthalpy]

The properties of high purity well ordered graphite are reasonably well known.

 

I've never found two suppliers of graphite giving similar measures for their products, so if books happen to give identical figures, then only because of copying on an other, or as a result of some computation of a material nobody has ever produced. Differences are disturbing for an element, like several % for the density.

 

I stand by my claim that graphite doesn't burn. Mainly because I couldn't light an air suspension of graphite particles, about 50nm in size (lubricant), in a flame. I consider a material that doesn't burn under such conditions won't as a block. MSDS tell the same. The regular use of graphite as an oven liner, as well.

At the provided link http://en.wikipedia.org/wiki/Windscale_fire in paragraph "Wigner energy" they tell:

"uranium fuel caught fire — not the graphite moderator as is widely assumed. A 2005 inspection showed that graphite damage was localised around burning fuel elements".