Urea Purification

Urea Pu rifica tion

Disclaimer: This tutorial comes from www.goldrefiningforum.com and can't be copied or reproduced without my authorization. This CAN'T be sold. By reading this, you agree to these terms. I'm not responsible of what you do with this stuff. This tutorial is only for informative purpose. Remember: Always wear good protection if you deal with chemicals. At the minimum, chemical resistant gloves and a respirator with acid gases cartridges.

Sa fety : Urea is not considered as corrosive. Toxic ammonia gases can be released when heating Urea.

Parts list: -Your Urea -One 4 liters bottle -One measuring cup (1000ml or more) -Coffee Filters -Funnel -Hotplate (optional but recommended) -Mortar and Pestle ------------------------------------------------------------------------1. First of all, put 500ml of Urea in your measuring cup and add hot water until you reach the 1 liter line. Swirl until all the urea dissolves.

2. When everything is dissolved, let sit 1 hour (you want the particles to settle). Your liquid will be very brown and will clear a little when it settles.

This is the sediments you don't want ;) 3. Now filter the liquid but try not to disturb the sediments. Don't expect getting a clear liquid with coffee filters. If you have lab grade filters, you may get better purity. You should get a brown liquid with little or no sediments.

Interesting thing: I've let a coffee filter dry over night and look, Urea crystals have grown !

4. You now have two choices. You can keep the liquid and use it like this to neutralize the acid, or get back the Urea. Personally, I do both. I think the best way to recover the Urea is to evaporate the liquid with a vacuum. But I do not own a vacuum bell so I had to heat the liquid. The thing is, Urea decomposes at 120°C so you must be careful. It releases CO2 and ammonia when it decomposes. So if it smells ammonia, you know you are heating too much. But even if you go higher than 120°C, you won't loose that much Urea...

Ok dried crystals should look like this (or better):

Now, put all that stuff in your mortar and crush it with your pestle. (Maybe one could use a coffee grinder but I did not tried)

It looks much better right ?

Final pr oduct !:

I hope you enjoyed this tutorial. More will come soon. Feel free to Donate to help maintain this Forum. PM me (Noxx) for more info.

Copyright 2007, GoldRefiningForum.com