Urea sulfate synthesis (acid concentration?)

rommie

Hi all!

I am currently doing trials on different fertilizer production methods. I want to make urea sulfate crystals from fertilizer grade urea granules (46% N) and sulfuric acid. I suspect it would be a straightforward process, dissolve the urea in acid and precipitate the crystals and separate it from the mother liquor. I however have no idea what the concentration of the acid should be, I suspect it should be diluted but don't know to what percentage. I do not want to use concentrated sulfuric acid due to obvious safety reasons. Internet search has not yielded a recipe to make this either.
I did a similar experiment successfully with urea and 52% phosphoric acid, and got a good yield of urea phosphate crystals.
Any help is appreciated!!

Thanks
Rommie

chemisttree

What is the solubility of urea sulfate in water?

rommie

I can't seem to find a value, not even on msds sheets. But it's used as a liquid fertilizer in drip irrigation so I suppose its completely water soluble.

chemisttree

You can't go any further without that information unless you are willing to just guess or you intend to use too much water (too dilute acid) and concentrate it until the product precipitates.

rommie

The only other info I have is that the final product contains 25% N and 43% S.
I am still searching for solubility values....