temperature to oxidate metals(incinerations)

[arthur kierski]

i have rh foils mixed with copper nitrate,lead nitrate,silver nitrate---what temperature,should i use to incinerate and transforms these nitrates into oxides??? in an open door furnace
Arthur Kierski

 

[arthur kierski]

in the last thread,i might have made a mistake---because in drying this rh foils, in order to weight it ,i burned it with alcohol-----automatically,i transformed the metals salts mixed with the foils in oxides---- i should have asked ,if i could have done this in my furnace ,and at what temperature i should do it.

 

[g_axelsson]

Any nitrates should be water soluble, why not just wash it off?

If the question is how hot do you need it to turn trace nitric into oxides it differs depending on the metal, usually most nitrates breaks down at 500-600 C, glowing red heat should be enough.
If you have a sensitive scale you could always do a series of tests with an oven and find out when the rhodium flakes stop loosing weight with higher temperature.

Göran

 

[arthur kierski]

Thanks Axelson for your quick reply------i will follow your instructions of washing out the nittrates--- regards

 

[g_axelsson]

We usually use incineration after using nitric or hydrochloric acid and want to switch acid without dissolving precious metals. There will always be traces of acids after washing with water. If the next step is to dissolve the precious metal you can just ignore the incineration step, especially if you are going to dissolve the rhodium with fusion.

That said, in the spirit of Harold, he would have pointed out that there is sometimes an advantage to incinerate material even when going to aqua regia. You remove any carbon and the solution might be easier to filter afterwards.

Göran