Combustion temperature of diamond

How hot does diamond have to get to burn?

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"Richard Henry" <rphenry@home.com> wrote in message
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What does this url have to do with diamond?
\edit\find\diamond ......no hit.....,
anyway:
Around 1000° C and up diamond does undergo a phase change
into graphite which when exposed to air will burn like any other
form of carbon. Check google. Lots of info on it.
hanson

"hanson" <[Only registered users see links. ]> wrote in message
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Try this one.

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"Richard Henry" <[Only registered users see links. ]> wrote in message
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Yeah, they showed that on CNN and Fox earlier this afternoon.
hanson

I have seen a documentary about artificial diamonds they make in
General Electric. As a fun, they also burned a diamond. They took a
diamond, placed it in a clamp and used a welding torch to heat it
untill it glowed. Then they dropped this hot diamond straight into a
dewar full of liquid oxygen. I was impressed - It did not explode, but
the burning diamond was "floating" on the oxygen and burning with
bright yellowish-white flame.

But this is a hard core. There are very few oxidisable substances that
would not burn under these circumstances.


"hanson" <[Only registered users see links. ]> wrote in message news:<VDIob.10351$[Only registered users see links. ].pas.eart hlink.net>...

"Muhammar" <[Only registered users see links. ]> wrote in message
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[hanson]
[Muhammar]
[hanson]
The binding energy between the atoms in the surface of the to be
oxidized material, here cubic bulk diamond, is a factor which determines,
in addition to temperature, the speed by which this burning takes place.
The larger the surface per mass unit, which means the finer
the powder, the more attack surface does the diamond expose to
the oxidizing medium. This fact/property/situation/process condition
poses a problem in the manufacture of synthetic diamond.

It is exquisitely EASY to produce diamond. Practically any oxidation
deficient combustion of hydrocarbon, which produces soot, will
deliver a black powder that contains nano crystalline diamond. But,
here comes the bitch, it's the best kept secret by the nanoxx diamond
producers. It's their intimately guarded recipe of how to separate the
nano sized diamonds xx from graphite and other forms of carbon
without burning oxidizing a good portion of the desired diamond.
Traditional HNO3, PbO, SnO2, CrO3, NOx, ClOx, O, O2, O3, Peroxides,
MnO2, KmnO4, etc. have all proven to be way too nonselective.
How we did it......it's still classified.
hanson

> How we did it......it's still classified.

This is not too hard to guess. Graphite makes cation-radicals when
stirred with sodium or potassium metal melt. These super-hot complexes
of graphite are very reactive toward electrophiles (like CO2, for
example).

Another alternative for removing graphite is to use F2. But I would
rather work with the K/Na alloy then messing with fluorine.

Yet another alternative is to mix conc. H2SO4 with soot in a large
beaker and add 30-50% H2O2 *very slowly*.

Btw. russians are selling TNT-explosion produced nanodiamonds quite
cheaply (100g about $500) but they cook it with H2SO4/HNO3 to get the
soot out.