Sulfur reaction with metals

[sundriedtomato]

Dear all

I have 250g of Copper 250g of Tin and 250g of Sulfur.
Everything is in powdered form.
Heated up in closed container wit surrounding nitrogen flow to avoid contact with Oxygen.
Heating ramp is 3 hours to 1000K.

What reaction will be the leading reaction?
How to calculate how fast will S react with Metals and at what temperatures?
If there is excess of sulfur - in what form will it leave the vessel - S4, S8?

I am afraid that there will be huge formation of sulfur vapor and it can damage the oven and everything else.

I am still searching for a good book on Sulfur Chemistry and process engineering. If there is a good literature - please advise.

 

[Astronuc]

Has one tried writing the thermodynamic equations?

Cu + S = CuS
Sn + S = SnS

Also, one should apply on molar basis rather than mass.

250 gm of S is likely an excess of S. 250 g of S, would be about 7.8 moles.

250 gm of copper is about 3.9 moles Cu, 250 gm of tin is about 2.1 moles Sn.

Whatever their source, copper sulfides vary widely in composition with 0.5 ≤ Cu/S ≤ 2, including numerous non-stoichiometric compounds.
http://en.wikipedia.org/wiki/Copper_sulfide

 

[sundriedtomato]

So the next step would be to use thermodynamic databases to find values and calculate reaction energies? Will try that.

The trick is as Astronuc mentioned is that there are a lot of possibilities for Cu_xS_y and Sn_xS_y binaries formation. And it is quite hard to pinpoint the right amount of S for everything to go into the right side of euqtion. There is constantly increasing temperature, that should guide the process.

Rephrasing the question:
If I have slightly less S in the system - will ~3 hours be enough time for metals and sulfur to react?