Answer:
Black powder has 3 main ingredients: Sulfur ([tex]S[/tex]), charcoal ([tex]C_{7}H_{4}O[/tex]), and potassium nitrate ([tex]KNO_{3}[/tex]).
Charcoal is basically just burnt wood and potassium nitrate can easily be displaced.
Keep in mind that this is BLACK POWDER and not actual gunpowder. The difference between the both is significant since gunpowder has a lot more refining processes it has to go through to be actually used in firearms and such.
The percentage composition of black powder should be 75% Potassium Nitrate, 10% Sulfur, and 15% charcoal.
Should be noted that black powder is not a safe compound to deal with, as static friction could ignite it.
There are other alternatives to Black powder such as nitroglycerin (used in dynamites) which is way more powerful and useful in doing mines and exploration but is an extremely tricky and reactive substance to work with.
I do hope this is just for educational purposes because you need to be certified to even just experiment with this (and there are laws to synthesize such as well, which I won't take any responsibility for)
