Re: Black powder

That sulphur will not react pyrotechnically with charcoal by itself
does not rule out the possibility that it might function as a
secondary oxidizer in black powder. Bear in mind that saltpetre mixed
with sulphur alone will scarcely sustain combustion, and no one
disputes that saltpetre is an oxidizer.

Whether a redox reaction is pyrotechnic depends on its thermodynamics.
Aluminum gives off enough heat in burning that it can sustain a
reaction in which iron oxide is the oxidizer, as we see in thermite.
Carbon does not give off enough heat, and so its redox reaction with
iron oxide must be sustained by an outside supply of heat, as we see
in the smelting of iron ore.

In black powder the saltpetre is obviously the primary oxidizer, but
some of black powder's reaction products suggest that sulphur is not
only a fuel but that it (or one of its compounds intermediary in the
reaction) functions as a secondary oxidizer as well. How else do we
end up with potassium polysulphide, K2Sx, in the solid products of
combustion? Its presence is easily shewn by the evolution of hydrogen
sulphide when those products are mixed with an acid. If you want an
effective demonstration, try washing fired black powder cartridge
cases in vinegar. If sulphur served purely as a fuel, one would not
expect this, since it would all be oxidized and dissipated in the
gaseous products as SO2.


On Apr 2, 3:22 pm, robg...@xxxxxxxxxxx wrote:
On Apr 1, 8:53 pm, "hhc...@xxxxxxxxx" <hhc...@xxxxxxxxx> wrote:

In this particular situaotin, its sulfur being milled with charcoal,
an that is a very dangerous combination. at least for me.

Many newbies don't realize the days long forgotten when a mixure
consisting of only sulfur and zinc dust fueled our early  rockets.
Cutting to the bottom line, the role of sulfur as an oxidiser should
not be ignored.

So go ahead, try to ignite a confined charcoal-sulfur mixture.

.

Relevant Pages

  • Re: Black powder
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