Potassium Nitrate is a crystalline salt, KNO3; a strong oxidizer used especially in making gunpowder, as a fertilizer, and in medicine.
Potassium nitrate can be made by combining ammonium nitrate and potassium hydroxide. Potassium nitrate can also be produced by neutralizing nitric acid with potassium hydroxide. This reaction is highly exothermic
Weigh out 1 kg (2.2 lbs) of potassium nitrate to be purified. Put 500 ml of water in the 2 litre pot. Heat the pot containing the water over an electric or gas stove element and add approximately one half the potassium nitrate. Stir well to dissolve.