Stuck solution

[Harold_V]

In my mind if you need urea for much more than fertilizing the grass your doing something wrong.

It can have it's uses and I used it extensively when I was refining commercially because the information now so freely available on here just wasn't easy to come by. I refined much on a toll basis but fast returns of metal were required and frequently in karat form so speed was of the essence, not sure I'd use it now I know better but it was a case of needs must at the time. Even now with some jobs where you have an unknown amount of values to dissolve and over use of nitric is almost inevitable I will use it, it's never caused me problems and for speed it's hard to beat unless you have a few buttons spare to consume the nitric but for most of the processes talked about on the forum I agree it's use is for just testing to see if all the nitric has been used before attempting to precipitate your values or whether evaporation is needed.

All I can say is I refined for more than 20 years, strictly on a toll basis. I never used urea once, nor would I endorse its use. Following GSP's advice to use nitric sparingly, or using it according to a formula, then adding a gold button to consume any residual acid is what I endorse, and for reasons specified by butcher. I was never keen on the idea of adding ANYTHING to my solutions that wasn't necessary, right down to switching from ferrous sulfate to SO2 gas for precipitation. I truly believe that one learns better habits by learning to do it the right (hard?) way.

Harold

 

[Dr. Poe]

Like I stated before: Urea at 160 degrees F works, cold use of urea gums up the works and one single white bead is sufficient to verify no nitric in solution @ 160F. It's always best to do the math and use the least amount of nitric acid as possible.
But, tell me of a newbie that can do that. Dr. Poe

 

[Harold_V]

It's always best to do the math and use the least amount of nitric acid as possible. But, tell me of a newbie that can do that. Dr. Poe

Heh! That's pretty much how Hoke summed it up, albeit by choosing different words.

The hardest lesson for the new guy to learn appears to be allowing acids to work until they are exhausted. It can be a slow process, certainly made worse by working without added heat. I learned, early on, that heating was my friend.

Harold