Acid and alkaline pickling is a chemical treatment that removes oxides, calamine and contaminants from metal surfaces using specific solutions applied by immersion or spraying. It is used after welding, rolling or oxidation to restore surface cleanliness and prepare the metal for passivation, painting or galvanising.
The most common acids are hydrochloric acid and sulphuric acid for steels, followed by rinsing and, if necessary, neutralisation in an alkaline bath (e.g. sodium hydroxide). For aluminium and its alloys, special formulations are used that dissolve oxides without affecting the substrate.
It is used in sectors such as food, pharmaceuticals, nautical, biomedical, energy and oil & gas, where hygiene, aesthetics and corrosion resistance are critical. Typical purposes: removal of post-welding oxides and rust, uniform appearance, increased durability and reduced risk of corrosion.
Typical systems: immersion lines with acid/alkaline tanks, rinsing, neutralisation and drying stations, as well as spray tunnels and electrochemical systems for fast and controlled processing. The lines can be manual or automatic and configured for acid or alkaline cycles depending on the material and the finishing objective.
Ceever designs and manufactures automated immersion or spray pickling systems that are programmable and can be integrated with production management systems (MES).
