What is the chemistry involved in my experience of the spontaneous combustion of aerosol sulfer at room temperature?
During December of each year I build a compost piles of fresh horse manure for its decomposition into a rich organic soil additive for the application to my garden in the fall of the next year. I sprinkle sulfur and wood ashes on to the top of the load which is still on my truck before unloading so that the additives will mix in some what as I pitch the new manure on to the new pile.
The manure is fresh and emitting some ammonia and methane as it decomposes. After spreading about five gallons of wood ashes on top of the load I then sprinkled dusting sulfur on top of that.
The dusting sulfur is sulfur is which has been processed into a very fine powder. When I sprinkled this over the manure the powder in the air above the pile which was descending slowly burst into sheet flames lasting possibly two seconds. The color was bright red/orange. I repeated this thee times and the same thing happened each time.
Afterwards, what ever the fumes I had inhaled with out noticing, evidently caused me to not be able to take a full deep breath. It was as if the muscles of inspiration would not respond with sufficient strength. This lasted about two hours.
The air temperature was around 55 degrees when the spontaneous fire took place over the manure and there was no wind. What would the chemical reaction be which would cause the sulfur to have a combustion point at such a low temperature? Or was the sulfur possibly a catalyst for some other reaction?
Any help with this question would be much appreciated...............Thanks,John