50AE Posted July 9, 2010 Posted July 9, 2010 Long time ago, I tried to synthesize Sr(NO3)2 from technical SrCO3 and HNO3. I succeeded, but the product was hygroscopic and instead the white color of SrCO3, it turned brown.Now I got mre SrCO3 from the same guy. It's technical grade, but he doesn't know about its purity.I wonder if you guys know what the impurities could be. He mentioned calcium sulfate, strontium sulfate and a little calcium carbonate.If it's mainly calcium sulfate, I could purify the product by dissolving it completely, filtering it and evaporating the water. CaSO4 doesn't react with nitric.But I also wonder what is the contaminant that reacts with HNO3 and turns brown.
Arthur Posted July 9, 2010 Posted July 9, 2010 Depends on the shade of the "brown"! One sort of brown is oxidised organics, think burned sugar. Depends a lot on the concentration of the nitric acid used and the temperature at which you evaporated the solution. Have you recrystalised the brown stuff from water?
50AE Posted July 9, 2010 Author Posted July 9, 2010 It's light brown. The thing turned brown in manufacture. Concentration of HNO3 was 58%. I haven't tried to recrystallize yet.
Mumbles Posted July 10, 2010 Posted July 10, 2010 It sounds like there could be some organics perhaps then. Have you noticed any H2S evolution with the neutralization with nitric acid? A lot of the stuff we have here has SrS in it. It doesn't explain the brown color, but I was just curious.
Arthur Posted July 10, 2010 Posted July 10, 2010 At 58% the nitric could well be more of an oxidiser than you want. 30% nitric comes as pH down for some hydroponic purposes, and is generally uncontrolled as it's to dilute to do bad things with. Search Hydroponic suppliers in your locality. My local supplier is a few miles across town. not quite a walk though
50AE Posted July 11, 2010 Author Posted July 11, 2010 (edited) Sorry guys, I was wrong. The color is gray and not brown. It looks pretty much like clay.It is very fine, because most of it passes a coffee filter.The moist strontium nitrate smells like dirty socks.And no, I couldn't smell any H2S while synthesizing.The product doesn't want to dry. I think it will stay wet forever. Edited July 11, 2010 by 50AE
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