Acidic Aqueous Overview Acidic aqueous solutions are water-based mixtures with pH less than 7. Acidic cleaning is routinely used to remove scale, rust, and oxides from metals. The cleaners may contain mineral acids (hydrofluoric, sulfuric, phosphoric, nitric), chromic acids, or organic acids (acetic or oxalic). They also may contain detergents, chelating agents, and small amounts of water-miscible solvents. The choice of acid and additives depends on the type of metal to be cleaned and the type of soil to be removed. Hydrogen embrittlement can be caused in some metals by exposure to some acids. Heat treating and choice of acid can reduce or eliminate the embrittlement. Persons using acidic cleaners will need protection from the fumes, as well as gloves and eye protection. Waste disposal involves pH adjustment and may require removal of some soil components. The use of chelating agents can make the removal of dissolved metals from the used cleaner very difficult. State Information | Glossary | Conversion Checklist | Comments Home | Process Advisor | Alternatives | Links | Search All SAGE material, Copyright© 1992, Research Triangle Institute Last Update: 06 May 1997 sage@rti.org http://clean.rti.org/alt.cfm?id=ac&cat=ov