Noble Metals Dissolved without Aqua Regia

upstart writes in with an IRC submission for RandomFactor:

Noble metals dissolved without aqua regia[*]:

A common way of extracting noble metals from other materials is by dissolving that material in solution. However, dissolving noble metals remains a big challenge due to their low reactivity, and effective recycling of noble metals requires high dissolution rates and controllable selectivity.

'Noble metals can be dissolved using different hydrometallurgical methods. Unfortunately, all of them have drawbacks,' explains Serhiy Cherevko, who studies noble metal dissolution on a fundamental level at the Helmholtz Institute Erlangen-Nurnberg for Renewable Energy but was not involved in this research. 'The most common approach is to use hydrochloric acid as a complexing agent and nitric acid, chlorine, or hydrogen peroxide as an oxidant.'

A mixture of hydrochloric acid and nitric acid is also known as aqua regia, from the Latin for royal water, and is frequently used to dissolve gold and platinum in industry. However, it is a potentially dangerous mixture and there are environmental concerns related to its use. Because of this, there is a significant drive to find alternatives.

[...] Binnemans' team prepared a very concentrated mixture of hydrated AlCl3 and Al(NO3)3 to use as their solvent. They tested it on metal wires and spent automotive catalysts.

Read more of this story at SoylentNews.