Discussion

jaggederest: For extraction, you'd want to use different solvents that have different dissolving properties - usually something like water, ethanol, DCM, acetone, MEK, methanol, toluene or whatever.For strontium, it looks like it's relatively soluble in short chain alcohols (methanol/ethanol) compared to the other two, so you'd crash out the potassium perchlorate by dissolving the mixture in water, then reducing the temperature to cause perchlorate to drop out of solution, then mix in a moderate amount of methanol to crash the potassium nitrate out, being left with a reasonably pure strontium nitrate, that you could then hot filter and recrystallize in anhydrous methanol if you wanted >90% purity. One or two rounds of recrystallization will leave you in the high nineties, probably above 97%.This is a classic chemistry workup kind of problem and there are interesting engineering challenges embedded in it.Of course... practical people just buy technical grade strontium nitrate and make fireworks out of it directly, as the article says.

brazzy: Um... some context? What even are road flares? And why would I want to extract strontium nitrate from them?

red_admiral: (Road) flares aka. "pyros" are like fireworks that stay in place and give off bright light and heat. Their intended use is to warn others of accidents, or for a ship in distress, to help a coast guard helicopter find it. As safety devices, they're not hard to get in some countries/states.Extracting strontium nitrate lets you .. build explosives from readily available materials? Or it would except, as the page shows, you need a pretty good chemistry set and knowledge to do this, at which point you probably don't need pyros.I don't know if it's just a Europe thing, but pyros are illegally used a lot at soccer (EU: football) matches and other sporting events. Picture on this page: https://scottishfsa.org/pyros-burn-young-dundee-fan/

rob74: I'm from Germany, and I have never once seen a road flare used on an actual road. Not sure if they're even legal in the EU (sounds like a bad idea to carry explosive or highly combustible stuff around in your car?), here in Germany all you as the driver have to do to secure an accident site is set up a reflective "warning triangle" at a specified distance and wear a safety vest when outside the car. I have seen plenty of pyros at football matches, although I'm not sure those are being sold as "road flares".

jimnotgym: You can however buy 'distress flares' in most of Europe, since many seagoing craft are recommended or indeed required to have the nasty, dangerous things.

jimnotgym: >Some older flare formulations also had things such as pitch, asphalt, wax, tallow, potassium chlorate and black powder. Those are not likely to be part of modern flare formulations.Most of the formulations in the table have charcoal, potassium nitrate or other oxidiser, and sulfur. Surely, to say they don't contain black powder is semantics, when they contain the ingredients of black powder?

fergie: I'm missing some context here: Why do we want to extract strontium nitrate anyway?

dmurray: The author's home page reveals that he has an interest in amateur rocketry. Strontium nitrate doesn't sound suitable as a propellant, so I suppose he wants it to generate visual effects.https://spiegl.org/unsorted/unsorted.html

jfim: They're not typically used for passenger cars, but semi truck drivers and first responders use them since they're visible from farther away in both regular and low visibility situations like fog, rain, and at night.

bookofjoe: https://www.amazon.com/Visibility-Eco-Friendly-15-Minute-Saf...>Specified and approved by the Bureau of Explosives and Underwriters Laboratories. No expiration date on road flares, the date shown on the flare is manufactured date. Orion flares will burn in all weather conditions, waxed Flare w/Plastic Cap. 15 Minute Burn Time — Non Perchlorate Formula

Kuinox: They are not used in europe. The first time I saw one was in Japan last week.We have portable triangle reflector in Europe that are in every truck or car.

throwup238: Because we don’t have a Sigma Aldrich account.

flal_: They are mandatory on boats, even for smaller ones, and that's how you can get some in Europe.

NoSalt: I've always wanted to activate a road flare. It looks so cool when they do it on TV and the movies.

mikestew: Amazon and your local auto parts store both sell them, they’re not expensive, so what’s holding you back? Just remember that they burn for 20 minutes or so, and you can’t extinguish them. (Well, a bucket of sand works.)

NoSalt: To be honest, I would be slightly nervous about getting into trouble with the law.

dylan604: For what? What are you planning on doing with a lit road flare that would get you in trouble?

NoSalt: I thought it would be equivalent to calling in a "fake" emergency, or abusing the 911 system, or something like that.

lazide: Only if you do it in a place you’d otherwise not be able to have a fire. I wouldn’t recommend your living room, or the stairwell of you apartment complex.

jaggederest: And more importantly we don't want to pay.. $360 a kilo for reagent grade. Yikes.

tlavoie: How does your car move around _without_ containing explosive, highly combustible stuff?

rob74: Yeah, but that stuff is in a hermetically closed, impact-resistant container, and the flares are probably not...