Make Potassium Nitrate
Collecting bat guano from caves used to be the main way to obtain potassium nitrate - also known as saltpeter - but these days there's a much easier way to get what you need to make this basic component of science experiments, fertilizers and gunpowder. Pick up a few instant cold packs and a container of sodium-free salt and you're in business. See Step 1 to get started.
Steps
- Purchase your ingredients. You can make potassium nitrate using ingredients available at any drugstore. Make sure you read the labels on the ingredients you pick up to confirm that they contain exactly what you need. Here's what to get:
- An instant cold pack made with ammonium nitrate. You'll need 40 grams.
- A container of sodium-free salt, which is potassium chloride. You'll need 37 grams.
- If you don't already have one, pick up a small food scale so you can measure out exactly how much of each ingredient you need.
- You'll also need a coffee filter to filter the solution you make.
- Measure out 100 milliliters of water. Use a graduated cylinder or measuring cup to get the exact amount.
- Dissolve 40 grams of ammonium nitrate in the water. Pour it into the cup with the water and stir gently every few minutes until it looks completely dissolved. It shouldn't take long.
- Filter the solution through a coffee filter. Affix a coffee filter over the cup and filter the solution into a small saucepan. This will take care of any undissolved ammonium nitrate that might remain.
- Add 37 grams of potassium chloride and heat the solution. Heat it slowly, over low heat, stirring occasionally until the potassium chloride is completely dissolved. Do not let the solution come to a boil.
- Filter the solution into a freezer-safe container. Use another coffee filter to get rid of any remaining solids. You can filter it into a plastic or glass container, as long as it's freezer-safe.
- Chill the solution in the freezer. As it chills, nitrate crystals will begin to form. You can check on the solution every few minutes to see how it's progressing. When it seems as though no more crystals will form, the process is complete.
- Pour off the liquid. After the nitrate crystals form, you'll be left with liquid ammonium chloride. Pour it off and discard so that only the crystals remain in the container. Allow them to dry completely before grinding them down and using your potassium nitrate in science experiments or for other purposes.
Tips
- You can also make sodium nitrate by substituting the potassium hydroxide for 40 grams of sodium hydroxide and follow the same procedure as the video.
Warnings
- Potassium hydroxide is highly corrosive; wear gloves when working with it.
Things You'll Need
- An instant cold pack that contains ammonium nitrate
- Salt substitute that contains potassium chloride
- A kitchen scale
- Coffee filters
- Graduated cylinder or cup
- Saucepan
- Freezer-safe container
Related Articles
- Make Silver Nitrate
- Make Copper Sulfate
- Purge a Burette for a Titration
- Make Quicklime
