Hydrochloric acid regeneration - Wikipedia
Field of application. The commercially most relevant field of application for HCl regeneration processes is the recovery of HCl from waste pickle liquors from carbon-steel pickling lines. Other applications include the production of metal oxides such as, but not limited, to Al 2 O 3 and MgO, as well as rare-earth oxides, by pyrohydrolysis of aqueous metal chloride or rare-earth chloride solutions.