Is it necessary to heat Nitric to dissolve base metals?

[Lady_Leprechaun]

So I got GF caps off watch bands and they are currently being heated in 70% Nitric and distilled water. The heating thing is scaring the bageezus out of me and I am wondering if I can do this without the heat, even if it takes days, that is fine with me. And if I can do it at room temp , would I still dilute the Nitric or use the concentrate? I believe I still need the water to hold the base metals, but wanted to be sure.

Thank You!

 

[jarlowski1]

You can do the reaction without heat, however the rate of reaction is proportional to heat. So yes it would slow down a lot. You still need to dilute the nitric as the water will give the salts a place to go when dissolving. I think you are adding too much nitric at once and that is what is scaring you. The reaction vessel should (when filled with your material, water and acid) not be filled more than half way. When you start the reaction add only a small amount of nitric and let that react then add a small amount more. In other words don't just dump 50mls of nitric into a hot solution. The solution can be maintained at 50-60c and be quite tame. You just need to control your nitric additions and then you will be more comfortable with it.

 

[Lady_Leprechaun]

Thanks! I'll let it sit at room temp for a few days, and next time I use heat I'll go very slow with the nitric. I am a big chicken when it comes to these chemicals.

 

[nickvc]

Using heat ensures that the nitric is used up so as most have a hard time sourcing and or have to pay extortionate prices for it it’s worth doing, as the previous poster recommended cover the items in water and add small increments of acid allowing it to work before adding more.

 

[goldenchild]

Without heat you wont get the most out of your nitric. And there will also be pieces that won't react without heat. You'll notice this especially when the solution starts becoming very saturated with base metals. No matter how much acid you add the metal won't dissolve. You're better off heating the reaction the whole way through so you know exactly when all the nitric is spent. If you can't get over the fear of heating reactions then refining may not be for you.