Beaker popping during the final stages of the nitric boils.

[Shark]

Many times when running a reaction I have had to keep the heat low to avoid this. If I had known that broken ceramics could have helped it would have been useful. Sometime higher heat is very useful.

Would pieces of broken ceramic processors work for this? I still have several that need processed.

 

[Alondro]

Using glass marbles seems like a decent idea, how many glass marbles did you use..?
I have a 1/2lt beaker I which I process about 50gms of fine gold.

Well, it all depends on the volume of solution. For my relatively small amounts in just a 1L beaker, I just need 2 at a time. Large amounts in large vessels will require more than that.

 

[Amol Gupta]

Here is a video demonstrating using 'boiling chips' as they call it.

 

[Martijn]

Here is a video demonstrating using 'boilng chips' as they call it.

That's for boiling sulfuric and is quite different than a nitric digestion.
Would not boiling be an option to avoid the popping?

What I do is heat and monitor the temperature and turn dowm the heat enough to keep it from boiling.

I'm not sure if this is related but I was using a watch dish that was much larger for the beaker, it covered the spout and was limiting the amount of vapours that could escape resulting in expulsions that were a lot more violent, opening the spout a bit allowed for the vapours to escape, I still had some popping but a lot less violent.

The dish is keeping hot gases inside, holding the heat in and making the solution boil harder.
It's a balance of how much heat is put in versus how much is lost.
Like with cooking food, turn down the heat once it boils or it will overflow. Take off the lid and the boiling instantly becomes a lot less violent as the heat escapes.

 

[Amol Gupta]

That's for boiling sulfuric and is quite different than a nitric digestion.
Would not boiling be an option to avoid the popping?

What I do is heat and monitor the temperature and turn dowm the heat enough to keep it from boiling.


The dish is keeping hot gases inside, holding the heat in and making the solution boil harder.
It's a balance of how much heat is put in versus how much is lost.
Like with cooking food, turn down the heat once it boils or it will overflow. Take off the lid and the boiling instantly becomes a lot less violent as the heat escapes.

Removing the lid from a beaker full of boiling nitric acid that can pop anytime is an idea that scares me.

 

[Martijn]

Removing the lid from a beaker full of boiling nitric acid that can pop anytime is an idea that scares me.

Yes, I agree. Then turning the heat off would be best. I just attempted to explain the phenomena you asked about.