cocktail76 Posted February 27, 2007 Share Posted February 27, 2007 How hygroscopic is Strontium nitrate if at all? Why do so many formulas use Strontium carbonate? What are the advatage of disadvantage of each? in red star formulas? Link to comment Share on other sites More sharing options...
DeAdFX Posted February 27, 2007 Share Posted February 27, 2007 Hmm.. This isn't a great answer but. I just recieved an order for SrCO3 and Sr(NO3)2. I assume that the nitrate is hydroscopic because it is very lumpy while the carbonate isn't. Take a look in the flash powder thread and you will notice the differences in reds between SrCO3 and Sr(NO3)2 Link to comment Share on other sites More sharing options...
Frozentech Posted February 27, 2007 Share Posted February 27, 2007 How hygroscopic is Strontium nitrate if at all? Why do so many formulas use Strontium carbonate? What are the advatage of disadvantage of each? in red star formulas? Strontium NItrate is very hygroscopic. I don't know a 'measurement' for it's hygroscopicity, but I have had best results using it after drying it at 100C for 2 hours, then rescreening it through 100 mesh. Strontium Carbonate is practically insouble, not hygroscopic at all. Strontium Nitrate, in addition to being a red colorant, is an oxidizer in pyrotechnics. It also is liable to give the same nitrate / aluminum reactions that KNO3 does. That said, as an oxidizer, it's more hazardous to ship. Strontium Carbonate is a weak base, which means it can dual do dual use as a buffering agent in certain comps. It's more stable and safer to work with as well. Link to comment Share on other sites More sharing options...
gomis Posted February 27, 2007 Share Posted February 27, 2007 In my experience, the source of pyrotechnic chemicals has A LOT to say regarding the qualities of the compound. I have been using Sr(NO3)2 that got a "non-hygroscopic-look" same as SrCO3. I use to keep a silica bag in every jar in order to keep them dry, and till now I have been using Sr(NO3)2 along with magensium with no problems. Many misunderstandings resgarding the Mg-Sr(NO3)2 compos and dangers can be read and found out there. Most of them, opinions given like laws by folks that did not had thouse chemicals in their hands ever. In the specific case of Mg and Nitrates (we keep the amoinum nitrate case apart for obvious reasons...), the ONLY problem that you can focus is that the water contained in the nitrates will react SLOWLY (that slowly is more than seconds, minutes, hours and days...), generating NOT an exotermic reaction. Generation of gases like hydrogen or oxides will be produced after some time, affecting the performance of the pyrotechnic composition. When you go through all the literature out there, it seems that you mix Mg, you mix Nitrates and....oh man! you're dead !! like if an espotaneous ignition will happen after a couple of miliseconds... Of course coating Mg is a good way to avoid any damage of the composition if gonna be stored a reasonable period of time. I do not know if someone has had any problems related with unexpected reactions. Link to comment Share on other sites More sharing options...
ewest Posted February 28, 2007 Share Posted February 28, 2007 How hygroscopic is Strontium nitrate if at all? Per Shimizu page 98...... Strontium Nitrate is soluble in 100gr of water: 40.1gr at 0 deg C89.4gr at 35 deg C93.4gr at 60 deg C96.9gr at 80 deg C104.9gr at 105 deg C When the caked strontium nitrate is heated to 200-300 deg C, it becomes a dry powder again. Link to comment Share on other sites More sharing options...
al93535 Posted February 28, 2007 Share Posted February 28, 2007 In my experience, the source of pyrotechnic chemicals has A LOT to say regarding the qualities of the compound. Thats exactly right! Sr nitrate itself is not that hygroscopic at all. Its the cheap material that comes with alot of sr chloride in it that is hygroscopic! I have real high purity sr nitrate and it does not cake, it does not absorb water, and in fact, you can use water and dextrin to bind it and it dries just like any other star. But of course, your location will affect results. If you live where its 90% RH all the time, your cheaper grade Sr nitrate will be almost unuseable. However if you live in a dry climate, you will find your cheaper sr nitrate quite useable and wonder what the fuss is all about Link to comment Share on other sites More sharing options...
fizeau Posted February 28, 2007 Share Posted February 28, 2007 Now I understand what you talking about. My Sr nitrate was never hygroscopic, it is homemade from HNO3 and SrCO3 and contents no chloride or other admixtures. Isn´t it possible to soluble your contamineted Sr(NO3)2 and recrystalize it, to get the chlorides out?OK, I think it´s painful to clean pounds of Sr nitrate in this way. And I´m not experienced in this operation, I´m only cleaning so my NaNO3. Why do I waste good HNO3 for simple nitrates? In my crazy country you can´t buy any nitrates unless NH4NO3, they are all very afraid of hobbyists, but HNO3 is cheaply availible... Link to comment Share on other sites More sharing options...
al93535 Posted March 1, 2007 Share Posted March 1, 2007 They would rather you make high explosives then fireworks. I mean gee, fireworks can start fires.. Link to comment Share on other sites More sharing options...
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