Do this procedure in a well ventilated area as chlorine gas is formed. You do not want that stuff in your lungs.
Potassium chlorate is a very reactive oxidiser and is a favourite among pyrotechnics. It’s the key ingredient in many types of flash powder, and here I’ll explain how to make it using nothing but household bleach and potassium based salt alternatives.
Get high chlorine bleach and pour it into a heat resistant glass or ceramic bowl (not metal), bring it to boil to evaporate the water and also to decompose the sodium hypochlorite into sodium chlorate and Sodium Chloride.
Keep heating until crystals of sodium chloride begin forming then take it off heat and allow to cool, placing in a fridge for best results. When cool, pour off the remaining liquid and discard the solid precipitate.
Next, measure out an equal amount of lukewarm water and dissolve into it your potassium based salt alternative (sold alongside regular table salt). After the water is saturated, ie: when no more can dissolve into it, pour it into your leftover bleach/sodium chlorate solution.
The sodium chlorate and potassium chloride will react to form potassium chlorate and sodium chloride.
Equation for this reaction:
KCl + NaCLO3 => NaCl + KClO3
The newly formed potassium chlorate will precipitate into crystals due to a difference in solubility, and then all you need to do is collect these crystals; most likely by running it through a coffee filter. Discard the liquid and admire your lovely white highly dangerous potassium chlorate.