# Ammonium chloride recovery and reusability?



## Kork86 (Nov 14, 2022)

Was wondering if NH4Cl crystals can be reused after PGM processing is complete? The process I use deposits iron in solution during the final step. I noticed rather clean looking crystals form once the waste solution cools down. In order to retrieve any values possibly left behind these crystals are dissolved and the same endothermic cooling takes place. 

If I were to recrystallize again after post step and wash the granules with a solution of NH4Cl would it be sufficient to reuse without producing iron impurities in latter runs? 
Or would increasing ph with ammonium hydroxide to drop the iron. Then once a clear solution is obtained. Use hcl to bring ph back down to around 6 and recrystalize. Would this produce a product free of iron contamination?

Im planning on doing some experimenting with this idea. My thoughts are that even if an iron impurity presents itself from this approach it can be easily removed from sponge given the inert nature of the PMs. Pd is a concern since it is moderately susceptible to be attacked by acid. But given the large quantity of ammonium chloride used for making saturated solutions and how much this would reduce waste solution volume. I thought I'd prod the community since web searching today has become a frustrating mess of irrelevant results.


Thanks for your time and attention,
The Torchenator


----------

