Non-Chemical urea

[harel238]

hello frinds
I read most of the book "C. M. Hoke's"
I did not see that the author refers to urea.
As neutralization of nitric acid .
Am I right ?
ariel

 

[Topher_osAUrus]

Correct.
Do not use urea, it complicates recovery of pgms. Even with use of zinc to cement them, it can still be troublesome.

It is suggested to evaporate off the excess nitric, with small additions of HCl.
Or to add a button of known weight and evaporate (which hastens the evaporating)

Or you can buy sulfamic acid, and add it. Which will get rid of the excess nitric, convert to sulfuric and precipotate lead sulfate out of solution. I believe this is the most commonly used methodology by board members now a days.