Re: drying carbon powder

Uncle Al <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
> Ben wrote:
> > 
> > A bit of safety advice needed here
> > 
> > I have some carbon powder which has some sort of coating or surfactant
> > on it. At the moment it is granulised; however, I want to get rid of
> > the coating and whatnot by heating in an oven to ~250-300°C in air. I
> > expect that this might result in some very fine (~20nm) carbon powder
> > becoming loose. Does which represent an explosion hazard? I have
> > breathing apparatus so I'm not worried about inhahation of the dust,
> > just the risk of explosion.
> 
> Finely dispersed carbon oxidizes or spontaneously ignites in air when
> heated.  Better to do it under inert gas (nitrogen or argon).  
> Pulling a hard dynamic vacuum and then heating is excellent but... you
> will have a right proper pisser of a problem with lofting particulates
> in the breeze.
> 
> It requires quite a bit of stuff in air, percentages, to form a dust
> explosion hazard. Coal dust is well documented; finer particulates
> will be more reactive.  The simple cover your butt is to do it under
> argon.
> 
> 20 nm dust won't be stopped by a mask.  Nanotubes could be an
> inhalation cancer hazard in the manner of asbestos and fiberglas
> microfibrils.  Non-pointy stuff doesn't have those problems.

Hmmm, the lofting of the particles is probably going to be a problem.
Since the purpose of doing this is to actually use the material after
I've got rid of the coating I think I'll be making an even bigger
problem for myself by baking off the organics. Time to make up plan B,
I think.

thanks for the advice

Ben