no precipitation?

[gear-golem]

hey ive just read something and ive wondered if its true. instead of vaporizing off all the excess nitric acid, you can add urea into the acid until it stops fizzing and then filter. anyone heard anything about this before and how effective is it and should i just stick with the vaporizing method

 

[glorycloud]

Most of the pros here recommend staying away from using urea and they
all seem to heartily recommend evaporation for the nitric. What they
really recommend is controlled addition of nitric so that there is no
need to evaporate off anything as no excess was used to start with. 8)

 

[gear-golem]

hey ive got another question, ive read elsewhere that it is possible to use zinc as a precipitant.is this actually true and what colour would the precipitated solids be (im sorry if this has already been asked but i couldnt find a definite answer for this and im still partially learning) and a chemical name for this too would be appreciated

thanks

 

[qst42know]

Zinc would displace all the metals in solution below it on the list. The activity or reactivity series of metals. Keep in mind this is a simplified list.

http://www.files.chem.vt.edu/RVGS/ACT/notes/activity_series.html

 

[nickvc]

Zinc dust is more commonly used in recovering values from cyanide solutions which will need further refining. It will precipitate gold from your solutions but the recovered metal would be far from pure and it's use is limited to recovery from disasters when the intent is to start refining from scratch,the link qst42know explains why.