Aluminium nitrate is a strong oxidising agent and aluminium chloride acts as a Lewis acid. Also these solutions are claimed to have the abilities of aqua regia and therefore can dissolve noble metals.
- Dissolution of noble metals in highly concentrated acidic salt solutions
Federica Forte, Sofia Riaño and Koen Binnemans, Chem. Commun., 2020, 56, 8230-8232, DOI: 10.1039/D0CC02298E
- Dissolving Noble Metals without Aqua Regia, David Bradley, Chemical Communications/Royal Society of Chemistry, 04 August 2020 DOI: 10.1002/chemv.202000071