Metal finishing uses a variety of materials and processes to coat, color and/or plate metallic and non-metallic substrate surfaces to create desired surface characteristics (examples of which include improving appearance, abrasion resistance or corrosion resistance). Typical supporting processes can include degreasing, cleaning, pickling, etching and/or polishing.
Chemicals and materials used in metal finishing include solvents, detergents and surfactants for cleaning; acids and bases for cleaning, etching and activating; and solutions of metal salts for depositing the finish onto the substrate. These chemicals are rinsed from the parts using rinse tanks that are often filled with deionized (DI) water, with a quality set point of >1 megohm. Waste rinse waters can be processed for recycle or discharge using Evoqua’s Waste Water Ion Exchange (WWIX) technologies, while spent process baths can be treated with Evoqua’s full line of neutralization and/or metals precipitation systems.