The action is by oxygen and water on a clean surface. It is our policy to passivate the SUS 316L and SUS 316LN austenitic SS tanks with 14% by volume cold Nitric acid. It is also our policy not to include hydrofluoric acid in a passivation solution. Hydro-flouric acid is a pickler which removes chromium and nickel along with heat hardened scale, it NOT a passivator. The concentrated acid you get on board in 200 litre drums is usually 68%. Contact time for Nitric acid is 2 hours.
Mineral salts can come in varieties. They are inorganic salts and include phosphate, calcium, chloride, sodium and potassium. One of the most common mineral salts is iodized salt. Iodine is essential to the function of the body as an iodine deficiency can be problematic.
Salt from a mine cannot be labelled as sea salt. The common name sea salts (note the plural) refers to a mixture of sodium chloride and other mineral salts. Sea salts do not have to meet the standard for salt and as such, do not have to be iodized. Sea salts are made from sea water and not mining. See Common Name for more information.