Washing cement silver with Sulphuric acid to rinse out copper.

[Martijn]

Once you have copper nitrate you can evaporate it down, staying below 80 degrees C to avoid decomposition of the nitrate, the salts can be converted with sulfuric acid and the copper sulfate can partially be removed by freezing a bottle and lowering solubility. Decant cold and you have a (stronger than compared to the HCL method) nitric back with some copper sulfate in it.

to get it clean, you need to distill it.

 

[Amol Gupta]

Once you have copper nitrate you can evaporate it down, staying below 80 degrees C to avoid decomposition of the nitrate, the salts can be converted with sulfuric acid and the copper sulfate can partially be removed by freezing a bottle and lowering solubility. Decant cold and you have a (stronger than compared to the HCL method) nitric back with some copper sulfate in it.

to get it clean, you need to distill it.

Either way I will have to distill it in all cases to get a fairly concentrated nitric acid