Sciencemadness Discussion Board

urea and potassium nitrate

cyanureeves - 11-12-2010 at 16:05

last year i bought hi-yield brand potassium nitrate stump remover and it was white as snow and so was their compost starter(urea). this year i can smell a difference in both and also see discoloration in both products.msds for both products remain the same though. does it take a while for companies to inform the public of their products?or is it google not keeping up?msds still shows that they are very pure. cas# are still the same. they show nothing else as other ingredient.

spong - 12-12-2010 at 00:50

It might not be a change in the ingredients, they may just be new batches of raw materials or they've tried to cut costs by buying lower grade materials. Also, pay little attention to the msds for purity, pvc primer says "MEK 1000ml/L" whena glance at the bottle shows it's loaded with a red dye and even without that Its still not 100% MEK.
A recrystalization should clean them up however :)

hkparker - 12-12-2010 at 11:12

It also depends on how you store them. If the cap is on loose and their in the sun, and its been a year im not surprised. Especially if you store then in closed areas with other chemicals, because gaseous impurities might get in and react over time. Either way, like spong said, a recrystallization will do it:)

cyanureeves - 12-12-2010 at 12:20

recrystalization? the urea how?isn't crystalization just heating and letting cool down?won't that do the same for the accompanying contaminants?i read urea doesn't dissolve in alcohol but 3lbs. of urea would call for alot of alcohol and what if the contaminants are also not alcohol soluble?i'd love to to purify my urea. it would save tons on shipping charges on e-bay which is where i had to go eventually.the only reason i bought hi-yield compost maker was because i recalled it being white as salt when i used it on my compost heap 2 summers ago.

cyanureeves - 12-12-2010 at 15:43

urea solubility is 51 grams/100ml water.at 68 deg.f. should i filter solution after i dissolve.

franklyn - 12-12-2010 at 16:32

Quote: Originally posted by cyanureeves  
urea solubility is 51 grams/100ml water.at 68 deg.f. should i filter solution after i dissolve.

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No , it's more like 100g urea per 100ml water. See PDF page 12 here
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1989001...

Filtration is always done first to separate out insoluble matter.
The soluble matter which is not urea will remain in the water
when urea crystalizes out.

http://www.sciencemadness.org/talk/viewthread.php?tid=2415&a...

Google this forum , the search is more detailed

.

cyanureeves - 12-12-2010 at 17:50

thank you gentlemen. i will try to purify and use to make potassium cyanate. at least silver nitrate did not find chloride in the urea. i'd rather use this oily looking urea if possible instead of my purer urea for potassium cyanate as sometimes i miss on the heating time and temp.all this sounds like the fast food burgers claiming 100% beef because 30% percent of the total patty is 100% beef.