Black powder is composed of charcoal, sulfur and a nitrate salt. The charcoal and sulfur serve as fuel and the nitrate is the oxidizing agent.
However, wouldn't it be cheaper to leave out the sulfur, thus having only charcoal as fuel?
Wikipedia says about this (emphasis added):
Black powder is a granular mixture of
- sulfur (S), which, while also serving as a fuel, lowers the temperature required to ignite the mixture, thereby increasing the rate of combustion.
I guess after this initial research my question boils down to: Why is sulfur required as an ingredient in gun powder, and how does it lower the ignition temperature of the mixture?