Gold parting valens") could be made by the distillation of saltpetre (KNO) with alum (KAl(SO)) or vitriol (FeSO) with water. 2KNO + HO + FeSO → FeO + KSO + 2HNO Nitric acid, after distillation to increase the acid strength, is capable of dissolving the silver but it will not (by itself) dissolve the gold. However, nitric acid is not able to (fully) extract silver and other impurities from an alloy with a high content of gold. Therefore, one part of scrap gold was typically alloyed with three parts of copper (quartering) before parting with nitric acid. Another method uses Sterling silver
Trifluoroacetic acid causes severe skin burns and is toxic for aquatic organisms even at low concentrations. TFA's reaction with bases and metals, especially light metals, is strongly exothermic. The reaction with lithium aluminium hydride (LAH) results in an explosion. TFA is not biodegradable and is somewhat toxic to aquatic life - although it does not bioaccumulate, prevention of release into waterways is of extreme importance when using TFA Trifluoroacetic acid Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CFCOH. It is a structural analogue of acetic acid with all three of the acetyl group’s hydrogen atoms replaced by fluorine