Certain compositions (like strobes) require the use of magnesium and ammonium perchlorate,and sometimes Mg needs to be protected from moisture. When these materials are going to come in contact with each other the magnesium needs to be coated with potassium dichromate. There are exceptional dangers to be aware of before attempting this process. Potassium dichromate is very toxic, you should not inhale it's dust or get any on your skin, proper protection is required. Magnesium reacts with water creating hydrogen gas and heat. This gas should be properly vented to prevent explosion. This process does not take long and is suitable for a beginner familiar with the safety measures of pyrotechnics.
Potassium Dichromate - A good rule of thumb is 5% of the magnesium by weight.
Magnesium - The smaller the particle size of the Mg the more surface area it has and the more potassium dichromate you will need.
Stirrer - I use a spoon.
Water - Somewhat hard to find, but a very useful resource...
Filters - Coffee filters work.
Containers - To mix everything in, to hold the dry chemicals, and to filter out the liquid from the mixture.
Paper - I use a heavy duty water resistant paper used for roofing, but kraft will work.
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Weigh out the magnesium. I used 500 grams for this process. Put the Mg in a container and set it aside. | |||
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Weigh out the potassium dichromate. I used a little over 25 grams from this process. | |||
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Mix your potassium dichromate with hot water (100 degrees C, or anywhere around boiling) and stir until it has all dissolved. The water will turn a funky color, a scary poisonous funky color. | |||
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Slowly pour magnesium in the solution and stir it. Add more water as needed. The Mg will react with the water and foam up, so be careful and add slowly. Hydrogen gas is being produced in this process, so it would be wise to do this outside away from an ignition source. There is nothing wrong with using an excess of water, the potassium dichromate will coat the Mg and stop the reaction just the same with or without a lot of water. |
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Keep stirring until the reaction completely stops. Stir for a couple of more minutes to ensure the magnesium is all coated. The potassium dichromate will grab onto the magnesium | |||
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Put a coffee filter into one of the containers and fill it with the slurry. Allow the liquid to drain out of the filter and pour the liquid back into the slurry. | |||
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Dump the drained magnesium onto the sheet for drying. When it is completely dry you can store it or use it in a composition. | |||
